Currently the ARC state (MFU/MRU) of cached L2ARC buffer and their
content type is unknown. Knowing this information may prove beneficial
in adjusting the L2ARC caching policy.
This commit adds L2ARC arcstats that display the aligned size
(in bytes) of L2ARC buffers according to their content type
(data/metadata) and according to their ARC state (MRU/MFU or
prefetch). It also expands the existing evict_l2_eligible arcstat to
differentiate between MFU and MRU buffers.
L2ARC caches buffers from the MRU and MFU lists of ARC. Upon caching a
buffer, its ARC state (MRU/MFU) is stored in the L2 header
(b_arcs_state). The l2_m{f,r}u_asize arcstats reflect the aligned size
(in bytes) of L2ARC buffers according to their ARC state (based on
b_arcs_state). We also account for the case where an L2ARC and ARC
cached MRU or MRU_ghost buffer transitions to MFU. The l2_prefetch_asize
reflects the alinged size (in bytes) of L2ARC buffers that were cached
while they had the prefetch flag set in ARC. This is dynamically updated
as the prefetch flag of L2ARC buffers changes.
When buffers are evicted from ARC, if they are determined to be L2ARC
eligible then their logical size is recorded in
evict_l2_eligible_m{r,f}u arcstats according to their ARC state upon
eviction.
Persistent L2ARC:
When committing an L2ARC buffer to a log block (L2ARC metadata) its
b_arcs_state and prefetch flag is also stored. If the buffer changes
its arcstate or prefetch flag this is reflected in the above arcstats.
However, the L2ARC metadata cannot currently be updated to reflect this
change.
Example: L2ARC caches an MRU buffer. L2ARC metadata and arcstats count
this as an MRU buffer. The buffer transitions to MFU. The arcstats are
updated to reflect this. Upon pool re-import or on/offlining the L2ARC
device the arcstats are cleared and the buffer will now be counted as an
MRU buffer, as the L2ARC metadata were not updated.
Bug fix:
- If l2arc_noprefetch is set, arc_read_done clears the L2CACHE flag of
an ARC buffer. However, prefetches may be issued in a way that
arc_read_done() is bypassed. Instead, move the related code in
l2arc_write_eligible() to account for those cases too.
Also add a test and update manpages for l2arc_mfuonly module parameter,
and update the manpages and code comments for l2arc_noprefetch.
Move persist_l2arc tests to l2arc.
Reviewed-by: Ryan Moeller <freqlabs@FreeBSD.org>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#10743
The ARC caches data in scatter ABD's, which are collections of pages,
which are typically 4K. Therefore, the space used to cache each block
is rounded up to a multiple of 4K. The ABD subsystem tracks this wasted
memory in the `scatter_chunk_waste` kstat. However, the ARC's `size` is
not aware of the memory used by this round-up, it only accounts for the
size that it requested from the ABD subsystem.
Therefore, the ARC is effectively using more memory than it is aware of,
due to the `scatter_chunk_waste`. This impacts observability, e.g.
`arcstat` will show that the ARC is using less memory than it
effectively is. It also impacts how the ARC responds to memory
pressure. As the amount of `scatter_chunk_waste` changes, it appears to
the ARC as memory pressure, so it needs to resize `arc_c`.
If the sector size (`1<<ashift`) is the same as the page size (or
larger), there won't be any waste. If the (compressed) block size is
relatively large compared to the page size, the amount of
`scatter_chunk_waste` will be small, so the problematic effects are
minimal.
However, if using 512B sectors (`ashift=9`), and the (compressed) block
size is small (e.g. `compression=on` with the default `volblocksize=8k`
or a decreased `recordsize`), the amount of `scatter_chunk_waste` can be
very large. On a production system, with `arc_size` at a constant 50%
of memory, `scatter_chunk_waste` has been been observed to be 10-30% of
memory.
This commit adds `scatter_chunk_waste` to `arc_size`, and adds a new
`waste` field to `arcstat`. As a result, the ARC's memory usage is more
observable, and `arc_c` does not need to be adjusted as frequently.
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Wilson <gwilson@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10701
A bunch of places need to edit files to incorporate the configured paths
i.e. bindir, sbindir etc. Move this logic into a common file.
Create arc_summary by copying arc_summary[23] as appropriate at build
time instead of install time.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10559
The meaning of the `free` field is currently `zfs_arc_sys_free`, which
is the target amount of memory to leave free for the system, and is
constant after booting.
This commit changes the meaning of `free` to arc_free_memory(), the
amount of memory that the ARC considers to be free.
It also adds a new arcstat field `avail`, which tracks
`arc_available_memory()`.
Since `avail` can be negative, it also updates the arcstat script to
pretty-print negative values.
example output:
$ arcstat -f time,miss,arcsz,c,grow,need,free,avail 1
time miss arcsz c grow need free avail
15:03:02 39K 114G 114G 0 0 2.4G 407M
15:03:03 42K 114G 114G 0 0 2.1G 120M
15:03:04 40K 114G 114G 0 0 1.8G -177M
15:03:05 24K 113G 112G 0 0 1.7G -269M
15:03:06 29K 111G 110G 0 0 1.6G -385M
15:03:07 27K 110G 108G 0 0 1.4G -535M
15:03:08 13K 108G 108G 0 0 2.2G 239M
15:03:09 33K 107G 107G 0 0 1.3G -639M
15:03:10 16K 105G 102G 0 0 2.6G 704M
15:03:11 7.2K 102G 102G 0 0 5.1G 3.1G
15:03:12 42K 103G 102G 0 0 4.8G 2.8G
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes#10494
The test added in commit
4313a5b4c5 ("Detect if sed supports --in-place")
doesn't work at least on my system (autoconfig-2.69).
The issue is that SED has already been found and cached before this
function is evaluated, with the result that the test is completely
skipped.
...
checking for a sed that does not truncate output... /usr/bin/sed
...
checking for sed --in-place... (cached) /usr/bin/sed
The first test is executed by libtool.m4. This looks to have been around
in libtool for at least 15 years or so, not sure why this was not
encountered at the time of the original commit.
Fix this by caching the value of the ac_inplace flag rather than the
path to SED. Also use $SED and add AC_REQUIRE to ensure that we use the
sed that was located by the standard configure test.
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes#10493
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: AJ Jordan <alex@strugee.net>
Closes#10288
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: AJ Jordan <alex@strugee.net>
Closes#10288
Changed interval value type from decimal to integer,
because of deprecation warning in Python 3.8 and above.
Also changed kstat values type from decimal to integer,
because all the values are integers.
Fixed behavior of arcstat when run without args.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Bartosz Zieba <bartosz@zieba.pro>
Closes#10132Closes#10142
Adding the FreeBSD code allows arc_summary and arcstat
to be used on FreeBSD.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#9641
Use sys.platform to choose the correct implementation of functions and
values of variables for the platform being run on.
Reword some comments to avoid describing implementation details in the
wrong places.
Reviewed-by: Kjeld Schouten <kjeld@schouten-lebbing.nl>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#9561
Not all versions of sed have the --in-place flag. Detect support for
the flag during ./configure and provide a fallback mechanism for those
systems where sed's behavior differs. The autoconf variable
${ac_inplace} can be used to choose the correct flags for editing a
file in place with sed.
Replace violating usages in Makefile.am with ${ac_inplace}.
Reviewed-by: Chris Dunlop <chris@onthe.net.au>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#9463
/usr/bin/env python3 is the suggested[1] shebang for Python in general
(likewise for python2) and is conventional across platforms. This eases
development on systems where python is not installed in /usr/bin
(FreeBSD for example) and makes it possible to develop in virtual
environments (venv) for isolating dependencies.
Many packaging guidelines discourage the use of /usr/bin/env, but since
this is the canonical way of writing shebangs in the Python community,
many packaging scripts are already equipped to handle substituting the
appropriate absolute path to python automatically.
Some RPM package builders lacking brp-mangle-shebangs need a small
fallback mechanism in the package spec to stamp the appropriate shebang
on installed Python scripts.
[1]: https://docs.python.org/3/using/unix.html?#miscellaneous
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Ryan Moeller <ryan@ixsystems.com>
Closes#9314
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Richard Laager <rlaager@wiktel.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Closes#9234
Almost all of the Python code in the respository has been updated
to be compatibile with Python 2.6, Python 3.4, or newer. The only
exceptions are arc_summery3.py which requires Python 3, and pyzfs
which requires at least Python 2.7. This allows us to maintain a
single version of the code and support most default versions of
python. This change does the following:
* Sets the default shebang for all Python scripts to python3. If
only Python 2 is available, then at install time scripts which
are compatible with Python 2 will have their shebangs replaced
with /usr/bin/python. This is done for compatibility until
Python 2 goes end of life. Since only the installed versions
are changed this means Python 3 must be installed on the system
for test-runner when testing in-tree.
* Added --with-python=<2|3|3.4,etc> configure option which sets
the PYTHON environment variable to target a specific python
version. By default the newest installed version of Python
will be used or the preferred distribution version when
creating pacakges.
* Fixed --enable-pyzfs configure checks so they are run when
--enable-pyzfs=check and --enable-pyzfs=yes.
* Enabled pyzfs for Python 3.4 and newer, which is now supported.
* Renamed pyzfs package to python<VERSION>-pyzfs and updated to
install in the appropriate site location. For example, when
building with --with-python=3.4 a python34-pyzfs will be
created which installs in /usr/lib/python3.4/site-packages/.
* Renamed the following python scripts according to the Fedora
guidance for packaging utilities in /bin
- dbufstat.py -> dbufstat
- arcstat.py -> arcstat
- arc_summary.py -> arc_summary
- arc_summary3.py -> arc_summary3
* Updated python-cffi package name. On CentOS 6, CentOS 7, and
Amazon Linux it's called python-cffi, not python2-cffi. For
Python3 it's called python3-cffi or python3x-cffi.
* Install one version of arc_summary. Depending on the version
of Python available install either arc_summary2 or arc_summary3
as arc_summary. The user output is only slightly different.
Reviewed-by: John Ramsden <johnramsden@riseup.net>
Reviewed-by: Neal Gompa <ngompa@datto.com>
Reviewed-by: loli10K <ezomori.nozomu@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8096
From, https://lintlyci.github.io/Flake8Rules/rules/W605.html
As of Python 3.6, a backslash-character pair that is not a valid
escape sequence now generates a DeprecationWarning. Although this
will eventually become a SyntaxError, that will not be for several
Python releases.
Note 'float_pobj' was simply removed from arcstat.py since it
was entirely unused.
Reviewed-by: John Kennedy <john.kennedy@delphix.com>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#8056
This change allows the arcstat.py script to handle unsupported options
gracefully and print both error and usage messages when one such option
is provided.
Reviewed-by: Giuseppe Di Natale <guss80@gmail.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: loli10K <ezomori.nozomu@gmail.com>
Closes#7799
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: George Melikov <mail@gmelikov.ru>
Signed-off-by: John Eismeier <john.eismeier@gmail.com>
Closes#7237
Otherwise, if arcstat gets interrupted before the desired number of
iterations is reached, the output file will be empty (both if set via
'-o' or via shell redirection).
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
Closes#6775
Fix new flake8 errors related to bare excepts and ambiguous
variable names due to a STYLE builder update.
Reviewed-by: George Melikov <mail@gmelikov.ru>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Closes#6776
Both scripts were returning an error code of 1
when using the -v argument. -v should exit with
an error code of 0.
Signed-off-by: Giuseppe Di Natale <dinatale2@llnl.gov>
Running arcstat.py -x currently throws KeyError due to rmis being
absent, it was removed in commit ca0bf58.
Signed-off-by: cable2999 <cable2999@users.noreply.github.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#3931
Build products from an out of tree build should be written
relative to the build directory. Sources should be referred
to by their locations in the source directory.
This is accomplished by adding the 'src' and 'obj' variables
for the module Makefile.am, using relative paths to reference
source files, and by setting VPATH when source files are not
co-located with the Makefile. This enables the following:
$ mkdir build
$ cd build
$ ../configure \
--with-spl=$HOME/src/git/spl/ \
--with-spl-obj=$HOME/src/git/spl/build
$ make -s
This change also has the advantage of resolving the following
warning which is generated by modern versions of automake.
Makefile.am:00: warning: source file 'xxx' is in a subdirectory,
Makefile.am:00: but option 'subdir-objects' is disabled
Signed-off-by: Turbo Fredriksson <turbo@bayour.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1082
Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Porting notes and other significant code changes:
The illumos 5368 patch (ARC should cache more metadata), which
was never picked up by ZoL, is mostly reverted by this patch.
Since ZoL relies on the kernel asynchronously calling the shrinker to
actually reap memory, the shrinker wakes up arc_reclaim_waiters_cv every
time it runs.
The arc_adapt_thread() function no longer calls arc_do_user_evicts()
since the newly-added arc_user_evicts_thread() calls it periodically.
Notable conflicting ZoL commits which conflicted with this patch or
whose effects are either duplicated or un-done by this patch:
302f753 - Integrate ARC more tightly with Linux
39e055c - Adjust arc_p based on "bytes" in arc_shrink
f521ce1 - Allow "arc_p" to drop to zero or grow to "arc_c"
77765b5 - Remove "arc_meta_used" from arc_adjust calculation
94520ca - Prune metadata from ghost lists in arc_adjust_meta
Trace support for multilist_insert() and multilist_remove() has been
added and produces the following output:
fio-12498 [077] .... 112936.448324: zfs_multilist__insert: ml { offset 240 numsublists 80 sublistidx 63 }
fio-12498 [077] .... 112936.448347: zfs_multilist__remove: ml { offset 240 numsublists 80 sublistidx 29 }
The following arcstats have been removed:
recycle_miss - Used by arcstat.py and arc_summary.py, both of which
have been updated appropriately.
l2_writes_hdr_miss
The following arcstats have been added:
evict_not_enough - Number of times arc_evict_state() was unable to
evict enough buffers to reach its target amount.
evict_l2_skip - Number of times arc_evict_hdr() skipped eviction
because it was being written to the l2arc.
l2_writes_lock_retry - Replaces l2_writes_hdr_miss. Number of times
l2arc_write_done() failed to acquire hash_lock (and re-tries).
arc_meta_min - Shows the value of the zfs_arc_meta_min module
parameter (see below).
The "index" column of the "dbuf" kstat has been removed since it doesn't
have a direct analog in the new multilist scheme. Additional multilist-
related stats could be added in the future but would likely require
extensions to the mulilist API.
The following module parameters have been added:
zfs_arc_evict_batch_limit - Number of ARC headers to free per sub-list
before moving on to the next sub-list.
zfs_arc_meta_min - Enforce a floor on the amount of metadata in
the ARC.
zfs_arc_num_sublists_per_state - Number of multilist sub-lists per
ARC state.
zfs_arc_overflow_shift - Controls amount by which the ARC must exceed
the target size to be considered "overflowing".
Ported-by: Tim Chase <tim@chase2k.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov
Added a handler for SIGWINCH, so that one header
is printed per screen even when the terminal resizes.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2847
The field descriptions from arcstat.py -v for the demand accesses
are inaccurate. They all begin with "Demand Data" yet the fields
actually covered both demand data and demand meta-data accesses.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2842
Stopping arcstat.py with ^C always ends up with error:
TypeError: sighandler() takes no arguments (2 given)
Since no special signal handling was done in sighandler(),
it's simpler to just set SIGINT handler to SIG_DFL, which
terminates the script.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Isaac Huang <he.huang@intel.com>
Closes#2179
Stopping arcstat.py with ^C always ends up with error:
TypeError: sighandler() takes no arguments (2 given)
This patch corrects the error by updating the signal handler
to take the correct number of arguments.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2182
Today arcstat.py prints one header every hdr_intr (20 by default)
lines. It would be more consistent with out utilities like vmstat
if hdr_intr defaulted to terminal window size, i.e. one header
per screenful of outputs.
Signed-off-by: Isaac Huang <he.huang@intel.com>
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#2183
Future proofing for compatibility with newer versions of Python.
Signed-off-by: Matthew Thode <prometheanfire@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1838
Update the code to follow the pep8 style guide.
References:
http://www.python.org/dev/peps/pep-0008/
Signed-off-by: Matthew Thode <prometheanfire@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1838
The dbufstat.py command was added to provide a conveniant way to
easily determine what ZFS is caching. The script consumes the
raw /proc/spl/kstat/zfs/dbufs kstat data can consolidates it in
to a more human readable form. This was designed primarily as
a tool to aid developers but it may also be useful for advanced
users who want more visibility in to what the ARC is caching.
When run without options dbufstat.py will default to showing a
list of all objects with at least one buffer present in the
cache. The total cache space consumed by that object will be
printed on the right along with the object type. Similar to the
arcstats.py command the -x option may used to display additional
fields.
Two other modes of operation are also supported by dbufstat.py
and the expectation is additional display modes may be added as
needed. The -t option will summerize the total number of bytes
cached for each object type, and the -b option will show every
dbuf currently cached.
The script was designed to be consistent with arcstat.py and
includes most of the same options and funcationality.
Signed-off-by: Prakash Surya <surya1@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
* Modified kstat_update() to read arcstats from proc.
* Fix shebang.
* Added Makefile.am entries for arcstat.py
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#1506
