mirror_zfs/include/os/linux/spl/sys
ednadolski-ix 3bd4df3841
Improve ZFS objset sync parallelism
As part of transaction group commit, dsl_pool_sync() sequentially calls
dsl_dataset_sync() for each dirty dataset, which subsequently calls
dmu_objset_sync().  dmu_objset_sync() in turn uses up to 75% of CPU
cores to run sync_dnodes_task() in taskq threads to sync the dirty
dnodes (files).

There are two problems:

1. Each ZVOL in a pool is a separate dataset/objset having a single
   dnode.  This means the objsets are synchronized serially, which
   leads to a bottleneck of ~330K blocks written per second per pool.

2. In the case of multiple dirty dnodes/files on a dataset/objset on a
   big system they will be sync'd in parallel taskq threads. However,
   it is inefficient to to use 75% of CPU cores of a big system to do
   that, because of (a) bottlenecks on a single write issue taskq, and
   (b) allocation throttling.  In addition, if not for the allocation
   throttling sorting write requests by bookmarks (logical address),
   writes for different files may reach space allocators interleaved,
   leading to unwanted fragmentation.

The solution to both problems is to always sync no more and (if
possible) no fewer dnodes at the same time than there are allocators
the pool.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Signed-off-by: Edmund Nadolski <edmund.nadolski@ixsystems.com>
Closes #15197
2023-11-06 10:38:42 -08:00
..
ia32 x86 asm: Replace .align with .balign 2023-01-24 09:04:39 -08:00
acl.h Clean up CSTYLEDs 2022-01-26 11:38:52 -08:00
atomic.h More aggsum optimizations 2021-06-07 09:02:47 -07:00
byteorder.h Reduce false positives from Static Analyzers 2022-09-30 15:30:12 -07:00
callb.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
callo.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
cmn_err.h spl: cmn_err_once() should be usable in brace-less if else statements 2023-03-15 11:13:25 -07:00
condvar.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
cred.h Linux 6.3 compat: idmapped mount API changes 2023-04-10 14:15:36 -07:00
ctype.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
debug.h Add VERIFY0P() and ASSERT0P() macros. 2023-09-19 17:21:55 -07:00
disp.h Cleanup: Use OpenSolaris functions to call scheduler 2022-09-12 09:55:37 -07:00
dkio.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
errno.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
fcntl.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
file.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
inttypes.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
isa_defs.h Add loongarch64 support 2023-04-25 16:05:45 -07:00
kmem_cache.h linux/spl/kmem_cache: undefine kmem_cache_alloc before defining it 2023-08-07 13:55:59 -07:00
kmem.h Use __attribute__((malloc)) on memory allocation functions 2023-05-26 15:47:52 -07:00
kstat.h Cleanup: Switch to strlcpy from strncpy 2022-09-27 16:35:29 -07:00
list.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
misc.h zed: mark disks as REMOVED when they are removed 2022-09-28 09:48:46 -07:00
mod_os.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
mutex.h Add mutex_enter_interruptible() for interruptible sleeping IOCTLs 2023-10-26 09:17:40 -07:00
param.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
proc.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
processor.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
procfs_list.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
random.h FreeBSD: fix compilation of FreeBSD world after 29274c9f6 2021-06-25 10:28:51 -07:00
rwlock.h Clean up CSTYLEDs 2022-01-26 11:38:52 -08:00
shrinker.h Linux 6.0 compat: register_shrinker() now var-arg 2022-08-08 16:18:30 -07:00
sid.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
signal.h Add SIGSTOP and SIGTSTP handling to issig 2021-04-15 13:34:35 -07:00
simd.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
stat.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
string.h Forbid b{copy,zero,cmp}(). Don't include <strings.h> for <string.h> 2022-03-15 15:13:48 -07:00
sunddi.h Remove hw_serial, ddi_strtoul() 2022-05-13 10:15:31 -07:00
sysmacros.h zfs_rename: support RENAME_* flags 2022-10-28 09:49:20 -07:00
systeminfo.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
taskq.h Improve ZFS objset sync parallelism 2023-11-06 10:38:42 -08:00
thread.h Switch from _Noreturn to __attribute__((noreturn)) 2022-03-23 08:51:00 -07:00
time.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
timer.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
trace_spl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
trace_taskq.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
trace.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
tsd.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
types32.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
types.h intptr_t definition is canonically signed 2023-07-14 16:32:49 -07:00
uio.h zvol: Remove broken blk-mq optimization 2023-10-24 14:37:52 -07:00
user.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
vfs.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
vmem.h Use __attribute__((malloc)) on memory allocation functions 2023-05-26 15:47:52 -07:00
vmsystm.h Add membar_sync 2022-09-20 15:32:44 -07:00
vnode.h Consolidate zfs_holey and zfs_access 2020-10-31 09:40:08 -07:00
wait.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
wmsum.h Introduce write-mostly sums 2021-05-27 14:27:29 -06:00
zmod.h Replace ZFS on Linux references with OpenZFS 2020-10-08 20:10:13 -07:00
zone.h Add Linux namespace delegation support 2022-06-10 09:51:46 -07:00