Alexander Motin 04bae5ec95 Disable high priority ZIO threads on FreeBSD and Linux ... High priority threads are handling ZIL writes. While there is no ZIL compression, there is encryption, checksuming and RAIDZ math. We've found that on large systems 1 taskq with 5 threads can be a bottleneck for throughput, IOPS or both. Instead of just bumping number of threads with a risk of overloading CPUs and increasing latency, switch to using TQ_FRONT mechanism to increase sync write requests priority within standard write threads. Do not do it on Illumos, since its TQ_FRONT implementation is inherently unfair. FreeBSD and Linux don't have this problem, so we can do it there. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Rob Norris <robn@despairlabs.com> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored-By: iXsystems, Inc. Closes #16146		2024-05-03 09:53:34 -07:00
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spl.4	Linux: Cleanup taskq threads spawn/exit	2024-02-13 11:15:16 -08:00
zfs.4	Disable high priority ZIO threads on FreeBSD and Linux	2024-05-03 09:53:34 -07:00