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mirror_zfs/include/sys/trace_zil.h

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Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
#if defined(_KERNEL) && defined(HAVE_DECLARE_EVENT_CLASS)
#undef TRACE_SYSTEM
#define TRACE_SYSTEM zfs
Fix build failure with Linux 4.1 and FTRACE Signed-off-by: Frédéric VANNIÈRE <f.vanniere@planet-work.com> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #3546
2015-07-28 15:42:14 +03:00
#undef TRACE_SYSTEM_VAR
#define TRACE_SYSTEM_VAR zfs_zil
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
#if !defined(_TRACE_ZIL_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_ZIL_H
#include <linux/tracepoint.h>
#include <sys/types.h>
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
#define ZILOG_TP_STRUCT_ENTRY \
__field(uint64_t, zl_lr_seq) \
__field(uint64_t, zl_commit_lr_seq) \
__field(uint64_t, zl_destroy_txg) \
__field(uint64_t, zl_replaying_seq) \
__field(uint32_t, zl_suspend) \
__field(uint8_t, zl_suspending) \
__field(uint8_t, zl_keep_first) \
__field(uint8_t, zl_replay) \
__field(uint8_t, zl_stop_sync) \
__field(uint8_t, zl_logbias) \
__field(uint8_t, zl_sync) \
__field(int, zl_parse_error) \
__field(uint64_t, zl_parse_blk_seq) \
__field(uint64_t, zl_parse_lr_seq) \
__field(uint64_t, zl_parse_blk_count) \
__field(uint64_t, zl_parse_lr_count) \
__field(uint64_t, zl_cur_used) \
__field(clock_t, zl_replay_time) \
__field(uint64_t, zl_replay_blks)
#define ZILOG_TP_FAST_ASSIGN \
__entry->zl_lr_seq = zilog->zl_lr_seq; \
__entry->zl_commit_lr_seq = zilog->zl_commit_lr_seq; \
__entry->zl_destroy_txg = zilog->zl_destroy_txg; \
__entry->zl_replaying_seq = zilog->zl_replaying_seq; \
__entry->zl_suspend = zilog->zl_suspend; \
__entry->zl_suspending = zilog->zl_suspending; \
__entry->zl_keep_first = zilog->zl_keep_first; \
__entry->zl_replay = zilog->zl_replay; \
__entry->zl_stop_sync = zilog->zl_stop_sync; \
__entry->zl_logbias = zilog->zl_logbias; \
__entry->zl_sync = zilog->zl_sync; \
__entry->zl_parse_error = zilog->zl_parse_error; \
__entry->zl_parse_blk_seq = zilog->zl_parse_blk_seq; \
__entry->zl_parse_lr_seq = zilog->zl_parse_lr_seq; \
__entry->zl_parse_blk_count = zilog->zl_parse_blk_count;\
__entry->zl_parse_lr_count = zilog->zl_parse_lr_count; \
__entry->zl_cur_used = zilog->zl_cur_used; \
__entry->zl_replay_time = zilog->zl_replay_time; \
__entry->zl_replay_blks = zilog->zl_replay_blks;
#define ZILOG_TP_PRINTK_FMT \
"zl { lr_seq %llu commit_lr_seq %llu destroy_txg %llu " \
"replaying_seq %llu suspend %u suspending %u keep_first %u " \
"replay %u stop_sync %u logbias %u sync %u " \
"parse_error %u parse_blk_seq %llu parse_lr_seq %llu " \
"parse_blk_count %llu parse_lr_count %llu " \
"cur_used %llu replay_time %lu replay_blks %llu }"
#define ZILOG_TP_PRINTK_ARGS \
__entry->zl_lr_seq, __entry->zl_commit_lr_seq, \
__entry->zl_destroy_txg, __entry->zl_replaying_seq, \
__entry->zl_suspend, __entry->zl_suspending, \
__entry->zl_keep_first, __entry->zl_replay, \
__entry->zl_stop_sync, __entry->zl_logbias, __entry->zl_sync, \
__entry->zl_parse_error, __entry->zl_parse_blk_seq, \
__entry->zl_parse_lr_seq, __entry->zl_parse_blk_count, \
__entry->zl_parse_lr_count, __entry->zl_cur_used, \
__entry->zl_replay_time, __entry->zl_replay_blks
#define ITX_TP_STRUCT_ENTRY \
__field(itx_wr_state_t, itx_wr_state) \
__field(uint8_t, itx_sync) \
__field(zil_callback_t, itx_callback) \
__field(void *, itx_callback_data) \
__field(uint64_t, itx_oid) \
\
__field(uint64_t, lrc_txtype) \
__field(uint64_t, lrc_reclen) \
__field(uint64_t, lrc_txg) \
__field(uint64_t, lrc_seq)
#define ITX_TP_FAST_ASSIGN \
__entry->itx_wr_state = itx->itx_wr_state; \
__entry->itx_sync = itx->itx_sync; \
__entry->itx_callback = itx->itx_callback; \
__entry->itx_callback_data = itx->itx_callback_data; \
__entry->itx_oid = itx->itx_oid; \
\
__entry->lrc_txtype = itx->itx_lr.lrc_txtype; \
__entry->lrc_reclen = itx->itx_lr.lrc_reclen; \
__entry->lrc_txg = itx->itx_lr.lrc_txg; \
__entry->lrc_seq = itx->itx_lr.lrc_seq;
#define ITX_TP_PRINTK_FMT \
"itx { wr_state %u sync %u callback %p callback_data %p oid %llu" \
" { txtype %llu reclen %llu txg %llu seq %llu } }"
#define ITX_TP_PRINTK_ARGS \
__entry->itx_wr_state, __entry->itx_sync, __entry->itx_callback,\
__entry->itx_callback_data, __entry->itx_oid, \
__entry->lrc_txtype, __entry->lrc_reclen, __entry->lrc_txg, \
__entry->lrc_seq
#define ZCW_TP_STRUCT_ENTRY \
__field(lwb_t *, zcw_lwb) \
__field(boolean_t, zcw_done) \
__field(int, zcw_zio_error) \
#define ZCW_TP_FAST_ASSIGN \
__entry->zcw_lwb = zcw->zcw_lwb; \
__entry->zcw_done = zcw->zcw_done; \
__entry->zcw_zio_error = zcw->zcw_zio_error;
#define ZCW_TP_PRINTK_FMT \
"zcw { lwb %p done %u error %u }"
#define ZCW_TP_PRINTK_ARGS \
__entry->zcw_lwb, __entry->zcw_done, __entry->zcw_zio_error
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
/*
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
* Generic support for two argument tracepoints of the form:
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
*
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
* DTRACE_PROBE2(...,
* zilog_t *, ...,
* itx_t *, ...);
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
*/
Use cstyle -cpP in `make cstyle` check Enable picky cstyle checks and resolve the new warnings. The vast majority of the changes needed were to handle minor issues with whitespace formatting. This patch contains no functional changes. Non-whitespace changes are as follows: * 8 times ; to { } in for/while loop * fix missing ; in cmd/zed/agents/zfs_diagnosis.c * comment (confim -> confirm) * change endline , to ; in cmd/zpool/zpool_main.c * a number of /* BEGIN CSTYLED */ /* END CSTYLED */ blocks * /* CSTYLED */ markers * change == 0 to ! * ulong to unsigned long in module/zfs/dsl_scan.c * rearrangement of module_param lines in module/zfs/metaslab.c * add { } block around statement after for_each_online_node Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov> Reviewed-by: Håkan Johansson <f96hajo@chalmers.se> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #5465
2016-12-12 21:46:26 +03:00
/* BEGIN CSTYLED */
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
DECLARE_EVENT_CLASS(zfs_zil_process_itx_class,
TP_PROTO(zilog_t *zilog, itx_t *itx),
TP_ARGS(zilog, itx),
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
TP_STRUCT__entry(
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
ZILOG_TP_STRUCT_ENTRY
ITX_TP_STRUCT_ENTRY
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
),
TP_fast_assign(
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
ZILOG_TP_FAST_ASSIGN
ITX_TP_FAST_ASSIGN
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
),
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
TP_printk(
ZILOG_TP_PRINTK_FMT " " ITX_TP_PRINTK_FMT,
ZILOG_TP_PRINTK_ARGS, ITX_TP_PRINTK_ARGS)
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
);
Use cstyle -cpP in `make cstyle` check Enable picky cstyle checks and resolve the new warnings. The vast majority of the changes needed were to handle minor issues with whitespace formatting. This patch contains no functional changes. Non-whitespace changes are as follows: * 8 times ; to { } in for/while loop * fix missing ; in cmd/zed/agents/zfs_diagnosis.c * comment (confim -> confirm) * change endline , to ; in cmd/zpool/zpool_main.c * a number of /* BEGIN CSTYLED */ /* END CSTYLED */ blocks * /* CSTYLED */ markers * change == 0 to ! * ulong to unsigned long in module/zfs/dsl_scan.c * rearrangement of module_param lines in module/zfs/metaslab.c * add { } block around statement after for_each_online_node Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov> Reviewed-by: Håkan Johansson <f96hajo@chalmers.se> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes #5465
2016-12-12 21:46:26 +03:00
/* END CSTYLED */
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
codebase style improvements for OpenZFS 6459 port
2017-01-21 00:17:55 +03:00
/* BEGIN CSTYLED */
OpenZFS 8585 - improve batching done in zil_commit() Authored by: Prakash Surya <prakash.surya@delphix.com> Reviewed by: Brad Lewis <brad.lewis@delphix.com> Reviewed by: Matt Ahrens <mahrens@delphix.com> Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Approved by: Dan McDonald <danmcd@joyent.com> Ported-by: Prakash Surya <prakash.surya@delphix.com> Problem ======= The current implementation of zil_commit() can introduce significant latency, beyond what is inherent due to the latency of the underlying storage. The additional latency comes from two main problems: 1. When there's outstanding ZIL blocks being written (i.e. there's already a "writer thread" in progress), then any new calls to zil_commit() will block waiting for the currently oustanding ZIL blocks to complete. The blocks written for each "writer thread" is coined a "batch", and there can only ever be a single "batch" being written at a time. When a batch is being written, any new ZIL transactions will have to wait for the next batch to be written, which won't occur until the current batch finishes. As a result, the underlying storage may not be used as efficiently as possible. While "new" threads enter zil_commit() and are blocked waiting for the next batch, it's possible that the underlying storage isn't fully utilized by the current batch of ZIL blocks. In that case, it'd be better to allow these new threads to generate (and issue) a new ZIL block, such that it could be serviced by the underlying storage concurrently with the other ZIL blocks that are being serviced. 2. Any call to zil_commit() must wait for all ZIL blocks in its "batch" to complete, prior to zil_commit() returning. The size of any given batch is proportional to the number of ZIL transaction in the queue at the time that the batch starts processing the queue; which doesn't occur until the previous batch completes. Thus, if there's a lot of transactions in the queue, the batch could be composed of many ZIL blocks, and each call to zil_commit() will have to wait for all of these writes to complete (even if the thread calling zil_commit() only cared about one of the transactions in the batch). To further complicate the situation, these two issues result in the following side effect: 3. If a given batch takes longer to complete than normal, this results in larger batch sizes, which then take longer to complete and further drive up the latency of zil_commit(). This can occur for a number of reasons, including (but not limited to): transient changes in the workload, and storage latency irregularites. Solution ======== The solution attempted by this change has the following goals: 1. no on-disk changes; maintain current on-disk format. 2. modify the "batch size" to be equal to the "ZIL block size". 3. allow new batches to be generated and issued to disk, while there's already batches being serviced by the disk. 4. allow zil_commit() to wait for as few ZIL blocks as possible. 5. use as few ZIL blocks as possible, for the same amount of ZIL transactions, without introducing significant latency to any individual ZIL transaction. i.e. use fewer, but larger, ZIL blocks. In theory, with these goals met, the new allgorithm will allow the following improvements: 1. new ZIL blocks can be generated and issued, while there's already oustanding ZIL blocks being serviced by the storage. 2. the latency of zil_commit() should be proportional to the underlying storage latency, rather than the incoming synchronous workload. Porting Notes ============= Due to the changes made in commit 119a394ab0, the lifetime of an itx structure differs than in OpenZFS. Specifically, the itx structure is kept around until the data associated with the itx is considered to be safe on disk; this is so that the itx's callback can be called after the data is committed to stable storage. Since OpenZFS doesn't have this itx callback mechanism, it's able to destroy the itx structure immediately after the itx is committed to an lwb (before the lwb is written to disk). To support this difference, and to ensure the itx's callbacks can still be called after the itx's data is on disk, a few changes had to be made: * A list of itxs was added to the lwb structure. This list contains all of the itxs that have been committed to the lwb, such that the callbacks for these itxs can be called from zil_lwb_flush_vdevs_done(), after the data for the itxs is committed to disk. * A list of itxs was added on the stack of the zil_process_commit_list() function; the "nolwb_itxs" list. In some circumstances, an itx may not be committed to an lwb (e.g. if allocating the "next" ZIL block on disk fails), so this list is used to keep track of which itxs fall into this state, such that their callbacks can be called after the ZIL's writer pipeline is "stalled". * The logic to actually call the itx's callback was moved into the zil_itx_destroy() function. Since all consumers of zil_itx_destroy() were effectively performing the same logic (i.e. if callback is non-null, call the callback), it seemed like useful code cleanup to consolidate this logic into a single function. Additionally, the existing Linux tracepoint infrastructure dealing with the ZIL's probes and structures had to be updated to reflect these code changes. Specifically: * The "zil__cw1" and "zil__cw2" probes were removed, so they had to be removed from "trace_zil.h" as well. * Some of the zilog structure's fields were removed, which affected the tracepoint definitions of the structure. * New tracepoints had to be added for the following 3 new probes: * zil__process__commit__itx * zil__process__normal__itx * zil__commit__io__error OpenZFS-issue: https://www.illumos.org/issues/8585 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5d95a3a Closes #6566
2017-12-05 20:39:16 +03:00
#define DEFINE_ZIL_PROCESS_ITX_EVENT(name) \
DEFINE_EVENT(zfs_zil_process_itx_class, name, \
TP_PROTO(zilog_t *zilog, itx_t *itx), \
TP_ARGS(zilog, itx))
DEFINE_ZIL_PROCESS_ITX_EVENT(zfs_zil__process__commit__itx);
DEFINE_ZIL_PROCESS_ITX_EVENT(zfs_zil__process__normal__itx);
/* END CSTYLED */
/*
* Generic support for two argument tracepoints of the form:
*
* DTRACE_PROBE2(...,
* zilog_t *, ...,
* zil_commit_waiter_t *, ...);
*/
/* BEGIN CSTYLED */
DECLARE_EVENT_CLASS(zfs_zil_commit_io_error_class,
TP_PROTO(zilog_t *zilog, zil_commit_waiter_t *zcw),
TP_ARGS(zilog, zcw),
TP_STRUCT__entry(
ZILOG_TP_STRUCT_ENTRY
ZCW_TP_STRUCT_ENTRY
),
TP_fast_assign(
ZILOG_TP_FAST_ASSIGN
ZCW_TP_FAST_ASSIGN
),
TP_printk(
ZILOG_TP_PRINTK_FMT " " ZCW_TP_PRINTK_FMT,
ZILOG_TP_PRINTK_ARGS, ZCW_TP_PRINTK_ARGS)
);
/* BEGIN CSTYLED */
#define DEFINE_ZIL_COMMIT_IO_ERROR_EVENT(name) \
DEFINE_EVENT(zfs_zil_commit_io_error_class, name, \
TP_PROTO(zilog_t *zilog, zil_commit_waiter_t *zcw), \
TP_ARGS(zilog, zcw))
DEFINE_ZIL_COMMIT_IO_ERROR_EVENT(zfs_zil__commit__io__error);
codebase style improvements for OpenZFS 6459 port
2017-01-21 00:17:55 +03:00
/* END CSTYLED */
Remove duplicate typedefs from trace.h Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Issue #2953
2014-12-13 05:07:39 +03:00
#endif /* _TRACE_ZIL_H */
#undef TRACE_INCLUDE_PATH
#undef TRACE_INCLUDE_FILE
#define TRACE_INCLUDE_PATH sys
#define TRACE_INCLUDE_FILE trace_zil
#include <trace/define_trace.h>
#endif /* _KERNEL && HAVE_DECLARE_EVENT_CLASS */
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