This change is an attempt to add visibility into the arc_read calls
occurring on a system, in real time. To do this, a list was added to the
in memory SPA data structure for a pool, with each element on the list
corresponding to a call to arc_read. These entries are then exported
through the kstat interface, which can then be interpreted in userspace.
For each arc_read call, the following information is exported:
* A unique identifier (uint64_t)
* The time the entry was added to the list (hrtime_t)
(*not* wall clock time; relative to the other entries on the list)
* The objset ID (uint64_t)
* The object number (uint64_t)
* The indirection level (uint64_t)
* The block ID (uint64_t)
* The name of the function originating the arc_read call (char[24])
* The arc_flags from the arc_read call (uint32_t)
* The PID of the reading thread (pid_t)
* The command or name of thread originating read (char[16])
From this exported information one can see, in real time, exactly what
is being read, what function is generating the read, and whether or not
the read was found to be already cached.
There is still some work to be done, but this should serve as a good
starting point.
Specifically, dbuf_read's are not accounted for in the currently
exported information. Thus, a follow up patch should probably be added
to export these calls that never call into arc_read (they only hit the
dbuf hash table). In addition, it might be nice to create a utility
similar to "arcstat.py" to digest the exported information and display
it in a more readable format. Or perhaps, log the information and allow
for it to be "replayed" at a later time.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The vn_rdwr() function performs I/O by calling the vfs_write() or
vfs_read() functions. These functions reside just below the system
call layer and the expectation is they have almost the entire 8k of
stack space to work with. In fact, certain layered configurations
such as ext+lvm+md+multipath require the majority of this stack to
avoid stack overflows.
To avoid this posibility the vn_rdwr() call in dump_bytes() has been
moved to the ZIO_TYPE_FREE, taskq. This ensures that all I/O will be
performed with the majority of the stack space available. This ends
up being very similiar to as if the I/O were issued via sys_write()
or sys_read().
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1399Closes#1423
3581 spa_zio_taskq[ZIO_TYPE_FREE][ZIO_TASKQ_ISSUE]->tq_lock is piping hot
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Christopher Siden <christopher.siden@delphix.com>
Reviewed by: Gordon Ross <gordon.ross@nexenta.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
References:
illumos/illumos-gate@ec94d32https://illumos.org/issues/3581
Notes for Linux port:
Earlier commit 08d08eb reduced contention on this taskq lock by simply
reducing the number of z_fr_iss threads from 100 to one-per-CPU. We
also optimized the taskq implementation in zfsonlinux/spl@3c6ed54.
These changes significantly improved unlink performance to acceptable
levels.
This patch further reduces time spent spinning on this lock by
randomly dispatching the work items over multiple independent task
queues. The Illumos ZFS developers stated that this lock contention
only arose after "3329 spa_sync() spends 10-20% of its time in
spa_free_sync_cb()" was landed. It's not clear if 3329 affects the
Linux port or not. I didn't see spa_free_sync_cb() show up in
oprofile sessions while unlinking large files, but I may just not
have used the right test case.
I tested unlinking a 1 TB of data with and without the patch and
didn't observe a meaningful difference in elapsed time. However,
oprofile showed that the percent time spent in taskq_thread() was
reduced from about 16% to about 5%. Aside from a possible slight
performance benefit this may be worth landing if only for the sake of
maintaining consistency with upstream.
Ported-by: Ned Bass <bass6@llnl.gov>
Closes#1327
Reviewed by: Matt Ahrens <matthew.ahrens@delphix.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>
NOTES: This patch has been reworked from the original in the
following ways to accomidate Linux ZFS implementation
*) Usage of the cyclic interface was replaced by the delayed taskq
interface. This avoids the need to implement new compatibility
code and allows us to rely on the existing taskq implementation.
*) An extern for zfs_txg_synctime_ms was added to sys/dsl_pool.h
because declaring externs in source files as was done in the
original patch is just plain wrong.
*) Instead of panicing the system when the deadman triggers a
zevent describing the blocked vdev and the first pending I/O
is posted. If the panic behavior is desired Linux provides
other generic methods to panic the system when threads are
observed to hang.
*) For reference, to delay zios by 30 seconds for testing you can
use zinject as follows: 'zinject -d <vdev> -D30 <pool>'
References:
illumos/illumos-gate@283b84606bhttps://www.illumos.org/issues/3246
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1396
3090 vdev_reopen() during reguid causes vdev to be treated as corrupt
3102 vdev_uberblock_load() and vdev_validate() may read the wrong label
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Christopher Siden <chris.siden@delphix.com>
Reviewed by: Garrett D'Amore <garrett@damore.org>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>
References:
illumos/illumos-gate@dfbb943217
illumos changeset: 13777:b1e53580146d
https://www.illumos.org/issues/3090https://www.illumos.org/issues/3102
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#939
2619 asynchronous destruction of ZFS file systems
2747 SPA versioning with zfs feature flags
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <gwilson@delphix.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Reviewed by: Dan Kruchinin <dan.kruchinin@gmail.com>
Approved by: Eric Schrock <Eric.Schrock@delphix.com>
References:
illumos/illumos-gate@53089ab7c8illumos/illumos-gate@ad135b5d64
illumos changeset: 13700:2889e2596bd6
https://www.illumos.org/issues/2619https://www.illumos.org/issues/2747
NOTE: The grub specific changes were not ported. This change
must be made to the Linux grub packages.
Ported-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: George Wilson <gwilson@zfsmail.com>
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
References:
https://www.illumos.org/issues/1693
Ported by: Martin Matuska <martin@matuska.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#678
Reviewed by: George Wilson <gwilson@zfsmail.com>
Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: Alexander Eremin <alexander.eremin@nexenta.com>
Reviewed by: Alexander Stetsenko <ams@nexenta.com>
Approved by: Richard Lowe <richlowe@richlowe.net>
References:
https://www.illumos.org/issues/1748
This commit modifies the user to kernel space ioctl ABI. Extra
care should be taken when updating to ensure both the kernel
modules and utilities are updated. If only the user space
component is updated both the 'zpool events' command and the
'zpool reguid' command will not work until the kernel modules
are updated.
Ported by: Martin Matuska <martin@matuska.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#665
Today zfs tries to allocate blocks evenly across all devices.
This means when devices are imbalanced zfs will use lots of
CPU searching for space on devices which tend to be pretty
full. It should instead fail quickly on the full LUNs and
move onto devices which have more availability.
Reviewed by: Eric Schrock <Eric.Schrock@delphix.com>
Reviewed by: Matt Ahrens <Matt.Ahrens@delphix.com>
Reviewed by: Adam Leventhal <Adam.Leventhal@delphix.com>
Reviewed by: Albert Lee <trisk@nexenta.com>
Reviewed by: Gordon Ross <gwr@nexenta.com>
Approved by: Garrett D'Amore <garrett@nexenta.com>
References to Illumos issue and patch:
- https://www.illumos.org/issues/510
- https://github.com/illumos/illumos-gate/commit/5ead3ed965
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #340
One of the neat tricks an autoconf style project is capable of
is allow configurion/building in a directory other than the
source directory. The major advantage to this is that you can
build the project various different ways while making changes
in a single source tree.
For example, this project is designed to work on various different
Linux distributions each of which work slightly differently. This
means that changes need to verified on each of those supported
distributions perferably before the change is committed to the
public git repo.
Using nfs and custom build directories makes this much easier.
I now have a single source tree in nfs mounted on several different
systems each running a supported distribution. When I make a
change to the source base I suspect may break things I can
concurrently build from the same source on all the systems each
in their own subdirectory.
wget -c http://github.com/downloads/behlendorf/zfs/zfs-x.y.z.tar.gz
tar -xzf zfs-x.y.z.tar.gz
cd zfs-x-y-z
------------------------- run concurrently ----------------------
<ubuntu system> <fedora system> <debian system> <rhel6 system>
mkdir ubuntu mkdir fedora mkdir debian mkdir rhel6
cd ubuntu cd fedora cd debian cd rhel6
../configure ../configure ../configure ../configure
make make make make
make check make check make check make check
This change also moves many of the include headers from individual
incude/sys directories under the modules directory in to a single
top level include directory. This has the advantage of making
the build rules cleaner and logically it makes a bit more sense.
