c/mirror_zfs
1
0
Fork 0
mirror of https://git.proxmox.com/git/mirror_zfs.git synced 2026-05-22 18:40:43 +03:00
Code Issues Packages Projects Releases Wiki Activity

Reduce number of metaslab preload taskq threads.

Browse Source 
Before this change ZFS created threads for 50% of CPUs for each top-
level vdev.  Plus it created the same number of threads for embedded
log groups (that have only one metaslab and don't need any preload).
As result, on system with 80 CPUs and pool of 60 vdevs this resulted
in 4800 metaslab preload threads, that is absolutely insane.

This patch changes the preload threads to 50% of CPUs in one taskq
per pool, so on the mentioned system it will be only 40 threads.

Among other things this fixes zdb on the mentioned system and pool
on FreeBSD, that failed to create so many threads in one process.

Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #15319
This commit is contained in:
Alexander Motin
2023-10-06 12:04:00 -04:00
committed by Brian Behlendorf
parent c27277daac
commit bcd010d3a5
6 changed files with 37 additions and 47 deletions
Download Patch File Download Diff File Expand all files Collapse all files
man/man4/zfs.4
+6
View File
@@ -402,6 +402,12 @@ Practical upper limit of total metaslabs per top-level vdev.
.It Sy metaslab_preload_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
Enable metaslab group preloading.
.
.It Sy metaslab_preload_limit Ns = Ns Sy 10 Pq uint
Maximum number of metaslabs per group to preload
.
.It Sy metaslab_preload_pct Ns = Ns Sy 50 Pq uint
Percentage of CPUs to run a metaslab preload taskq
.
.It Sy metaslab_lba_weighting_enabled Ns = Ns Sy 1 Ns | Ns 0 Pq int
Give more weight to metaslabs with lower LBAs,
assuming they have greater bandwidth,