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
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linux	Improve performance of zio_taskq_member	2020-03-03 10:29:38 -08:00
Makefile.am	OpenZFS restructuring - move platform specific headers	2019-09-05 09:34:54 -07:00