mirror_zfs/module
Matthew Ahrens 62840030a7 Reduce taskq and context-switch cost of zio pipe
When doing a read from disk, ZFS creates 3 ZIO's: a zio_null(), the
logical zio_read(), and then a physical zio. Currently, each of these
results in a separate taskq_dispatch(zio_execute).

On high-read-iops workloads, this causes a significant performance
impact. By processing all 3 ZIO's in a single taskq entry, we reduce the
overhead on taskq locking and context switching.  We accomplish this by
allowing zio_done() to return a "next zio to execute" to zio_execute().

This results in a ~12% performance increase for random reads, from
96,000 iops to 108,000 iops (with recordsize=8k, on SSD's).

Reviewed by: Pavel Zakharov <pavel.zakharov@delphix.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed by: George Wilson <george.wilson@delphix.com>
Signed-off-by: Matthew Ahrens <mahrens@delphix.com>
External-issue: DLPX-59292
Closes #7736
2018-08-02 15:51:45 -07:00
..
avl Update build system and packaging 2018-05-29 16:00:33 -07:00
icp Add support for selecting encryption backend 2018-08-02 11:59:24 -07:00
lua Update build system and packaging 2018-05-29 16:00:33 -07:00
nvpair OpenZFS 9580 - Add a hash-table on top of nvlist to speed-up operations 2018-07-30 11:30:03 -07:00
spl Add rwsem_tryupgrade for 4.9.20-rt16 kernel 2018-07-30 09:22:30 -07:00
unicode Update build system and packaging 2018-05-29 16:00:33 -07:00
zcommon OpenZFS 9337 - zfs get all is slow due to uncached metadata 2018-07-12 10:49:27 -07:00
zfs Reduce taskq and context-switch cost of zio pipe 2018-08-02 15:51:45 -07:00
.gitignore Prepare SPL repo to merge with ZFS repo 2018-05-29 14:51:39 -07:00
Makefile.in Update build system and packaging 2018-05-29 16:00:33 -07:00