mirror_zfs/module
Matthew Ahrens b3212d2fa6
Improve performance of zio_taskq_member
__zio_execute() calls zio_taskq_member() to determine if we are running
in a zio interrupt taskq, in which case we may need to switch to
processing this zio in a zio issue taskq.  The call to
zio_taskq_member() can become a performance bottleneck when we are
processing a high rate of zio's.

zio_taskq_member() calls taskq_member() on each of the zio interrupt
taskqs, of which there are 21.  This is slow because each call to
taskq_member() does tsd_get(taskq_tsd), which on Linux is relatively
slow.

This commit improves the performance of zio_taskq_member() by having it
cache the value of tsd_get(taskq_tsd), reducing the number of those
calls to 1/21th of the current behavior.

In a test case running `zfs send -c >/dev/null` of a filesystem with
small blocks (average 2.5KB/block), zio_taskq_member() was using 6.7% of
one CPU, and with this change it is reduced to 1.3%.  Overall time to
perform the `zfs send` reduced by 10% (~150,000 block/sec to ~165,000
blocks/sec).

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Serapheim Dimitropoulos <serapheim@delphix.com>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Tony Nguyen <tony.nguyen@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
Closes #10070
2020-03-03 10:29:38 -08:00
..
avl Wrap Linux module macros 2019-11-01 10:41:03 -07:00
icp Fix icp include directories for in-tree build 2020-02-20 08:10:47 -08:00
lua cppcheck: (error) Address of local auto-variable assigned 2019-12-18 17:25:42 -08:00
nvpair cppcheck: (warning) Possible null pointer dereference: nvh 2019-12-18 17:25:57 -08:00
os Improve performance of zio_taskq_member 2020-03-03 10:29:38 -08:00
spl OpenZFS restructuring - move platform specific sources 2019-09-06 11:26:26 -07:00
unicode Wrap Linux module macros 2019-11-01 10:41:03 -07:00
zcommon Prefer org.openzfs for features and properties 2020-02-18 09:36:50 -08:00
zfs Improve performance of zio_taskq_member 2020-03-03 10:29:38 -08:00
.gitignore Adapt gitignore for modules 2019-12-02 13:23:47 -08:00
Makefile.in module/Makefile.in: don't run xargs if empty 2019-10-08 10:10:23 -07:00