8a2a9db8df
ZFS Performance test concurrency should be lowered for better latency Work by Stephen Blinick. Nightly performance runs typically consist of two levels of concurrency; and both are fairly high. Since the IO runs are to a ZFS filesystem, within a zpool, which is based on some variable number of vdev's, the amount of IO driven to each device is variable. Additionally, different device types (HDD vs SSD, etc) can generally handle a different amount of concurrent IO before saturating. Nevertheless, in practice, it appears that most tests are well past the concurrency saturation point and therefore both perform with the same throughput, the maximum of the device. Because the queuedepth to the device(s) is so high however, the latency is much higher than the best possible at that throughput, and increases linearly with the increase in concurrency. This means that changes in code that impact latency during normal operation (before saturation) may not be apparent when a large component of the measured latency is from the IO sitting in a queue to be serviced. Therefore, changing the concurrency settings is recommended Authored by: Stephen Blinick <stephen.blinick@delphix.com> Reviewed-by: George Melikov <mail@gmelikov.ru> Reviewed-by: Giuseppe Di Natale <dinatale2@llnl.gov> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Dan Kimmel <dan.kimmel@delphix.com> Reviewed by: John Wren Kennedy <jwk404@gmail.com> Ported-by: John Wren Kennedy <jwk404@gmail.com> OpenZFS-issue: https://www.illumos.org/issues/9076 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/562 Upstream bug: DLPX-45477 Closes #7302 |
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| README.md | ||
README.md
ZFS Test Suite README
- Building and installing the ZFS Test Suite
The ZFS Test Suite runs under the test-runner framework. This framework is built along side the standard ZFS utilities and is included as part of zfs-test package. The zfs-test package can be built from source as follows:
$ ./configure
$ make pkg-utils
The resulting packages can be installed using the rpm or dpkg command as appropriate for your distributions. Alternately, if you have installed ZFS from a distributions repository (not from source) the zfs-test package may be provided for your distribution.
- Installed from source
$ rpm -ivh ./zfs-test*.rpm, or
$ dpkg -i ./zfs-test*.deb,
- Installed from package repository
$ yum install zfs-test
$ apt-get install zfs-test
- Running the ZFS Test Suite
The pre-requisites for running the ZFS Test Suite are:
- Three scratch disks
- Specify the disks you wish to use in the $DISKS variable, as a space delimited list like this: DISKS='vdb vdc vdd'. By default the zfs-tests.sh sciprt will construct three loopback devices to be used for testing: DISKS='loop0 loop1 loop2'.
- A non-root user with a full set of basic privileges and the ability to sudo(8) to root without a password to run the test.
- Specify any pools you wish to preserve as a space delimited list in the $KEEP variable. All pools detected at the start of testing are added automatically.
- The ZFS Test Suite will add users and groups to test machine to verify functionality. Therefore it is strongly advised that a dedicated test machine, which can be a VM, be used for testing.
Once the pre-requisites are satisfied simply run the zfs-tests.sh script:
$ /usr/share/zfs/zfs-tests.sh
Alternately, the zfs-tests.sh script can be run from the source tree to allow developers to rapidly validate their work. In this mode the ZFS utilities and modules from the source tree will be used (rather than those installed on the system). In order to avoid certain types of failures you will need to ensure the ZFS udev rules are installed. This can be done manually or by ensuring some version of ZFS is installed on the system.
$ ./scripts/zfs-tests.sh
The following zfs-tests.sh options are supported:
-v Verbose zfs-tests.sh output When specified additional
information describing the test environment will be logged
prior to invoking test-runner. This includes the runfile
being used, the DISKS targeted, pools to keep, etc.
-q Quiet test-runner output. When specified it is passed to
test-runner(1) which causes output to be written to the
console only for tests that do not pass and the results
summary.
-x Remove all testpools, dm, lo, and files (unsafe). When
specified the script will attempt to remove any leftover
configuration from a previous test run. This includes
destroying any pools named testpool, unused DM devices,
and loopback devices backed by file-vdevs. This operation
can be DANGEROUS because it is possible that the script
will mistakenly remove a resource not related to the testing.
-k Disable cleanup after test failure. When specified the
zfs-tests.sh script will not perform any additional cleanup
when test-runner exists. This is useful when the results of
a specific test need to be preserved for further analysis.
-f Use sparse files directly instread of loopback devices for
the testing. When running in this mode certain tests will
be skipped which depend on real block devices.
-d DIR Create sparse files for vdevs in the DIR directory. By
default these files are created under /var/tmp/.
-s SIZE Use vdevs of SIZE (default: 4G)
-r RUNFILE Run tests in RUNFILE (default: linux.run)
The ZFS Test Suite allows the user to specify a subset of the tests via a runfile. The format of the runfile is explained in test-runner(1), and the files that zfs-tests.sh uses are available for reference under /usr/share/zfs/runfiles. To specify a custom runfile, use the -r option:
$ /usr/share/zfs/zfs-tests.sh -r my_tests.run
- Test results
While the ZFS Test Suite is running, one informational line is printed at the
end of each test, and a results summary is printed at the end of the run. The
results summary includes the location of the complete logs, which is logged in
the form /var/tmp/test_results/[ISO 8601 date]. A normal test run launched
with the zfs-tests.sh wrapper script will look something like this:
$ /usr/share/zfs/zfs-tests.sh -v -d /mnt
--- Configuration --- Runfile: /usr/share/zfs/runfiles/linux.run STF_TOOLS: /usr/share/zfs/test-runner STF_SUITE: /usr/share/zfs/zfs-tests FILEDIR: /mnt FILES: /mnt/file-vdev0 /mnt/file-vdev1 /mnt/file-vdev2 LOOPBACKS: /dev/loop0 /dev/loop1 /dev/loop2 DISKS: loop0 loop1 loop2 NUM_DISKS: 3 FILESIZE: 4G Keep pool(s): rpool
/usr/share/zfs/test-runner/bin/test-runner.py -c
/usr/share/zfs/runfiles/linux.run -i /usr/share/zfs/zfs-tests
Test: .../tests/functional/acl/posix/setup (run as root) [00:00] [PASS]
...470 additional tests...
Test: .../tests/functional/zvol/zvol_cli/cleanup (run as root) [00:00] [PASS]
Results Summary PASS 472
Running Time: 00:45:09 Percent passed: 100.0% Log directory: /var/tmp/test_results/20160316T181651