|Summary:||cam iosched: The iops limiter should enforce limits below the quanta value and should not discard 'unspent' ios|
|Product:||Base System||Reporter:||Fabian Keil <fk>|
|Component:||kern||Assignee:||Warner Losh <imp>|
|Severity:||Affects Some People||CC:||emaste, imp|
Description Fabian Keil 2017-09-01 10:30:19 UTC
Created attachment 185971 [details] cam iosched: Enforce iop limits below the quanta value and preserve "unspent" ios Currently the iops limiter allows at least one iop per tick, as a result limits below the quanta value aren't enforced. ios that aren't used between ticks are lost, as a result the iops limiter can enforce a limit significantly below the configured maximum. The attached patch set fixes both issues. Obtained from: ElectroBSD
Comment 1 commit-hook 2017-09-22 02:37:10 UTC
A commit references this bug: Author: imp Date: Fri Sep 22 02:36:32 UTC 2017 New revision: 323893 URL: https://svnweb.freebsd.org/changeset/base/323893 Log: cam iosched: Enforce iop limits below the quanta value Previously the iops limiter would always allow at least quanta ios per second as cam_iosched_iops_tick() never set ios->l_value1 below 1. Submitted by: Fabian Keil <email@example.com> Obtained from: ElectroBSD PR: 221974 Changes: head/sys/cam/cam_iosched.c
Comment 2 commit-hook 2017-09-22 02:37:12 UTC
A commit references this bug: Author: imp Date: Fri Sep 22 02:36:36 UTC 2017 New revision: 323894 URL: https://svnweb.freebsd.org/changeset/base/323894 Log: cam iosched: Bettar account IOPS for smoother performance Prevent cam_iosched_iops_tick() from discarding 'unspent' ios unless it's a new accounting interval. Previously ios that weren't used between ticks were lost, as a result the iops limiter could enforce a limit below the configured maximum. Obtained from: ElectroBSD Submitted by: Fabian Keil PR: 221974 Changes: head/sys/cam/cam_iosched.c
Comment 3 Ed Maste 2018-12-04 14:12:38 UTC
imp, MFC plans?
Comment 4 Mark Linimon 2020-07-11 03:12:08 UTC
^Triage: Assign to committer resolving With bugmeister hat, I think any possible MFCs from 3 years ago are OBE.