Differential D45392

sched_4bsd: Rework ESTCPULIM() computation
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Authored by olce on May 27 2024, 10:28 PM.

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jhb
markj
mav
jeff

Commits

rG51a4ae05abe6: sched_4bsd: Remove RQ_PPQ from ESTCPULIM()'s formula
rGeebc148f25c3: sched_4bsd: ESTCPULIM(): Allow any value in the timeshare range
rGa454ff6b0440: sched_4bsd: Move ESTCPULIM() after its macro dependencies

Summary

Please see overview of project at D45393.

Move definition after dependent macros.
Remove RQ_PPQ from the formula. Substracting RQ_PPQ to the maximum number of allowed priority values (the factor to INVERSE_ESTCPU_WEIGHT) has the effect of pessimizing the number of processes assigned to the last priority bucket.
Allow any value in the (now enlarged) timeshare range. The previous formula wastes queues and degrades usage estimation precision, since any increase of ticks that makes adding more than 40 priorities is clamped to the last of these levels.

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rG FreeBSD src repository

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Event Timeline

olce created this revision.May 27 2024, 10:28 PM

Herald added a subscriber: imp. · View Herald TranscriptMay 27 2024, 10:28 PM

olce requested review of this revision.May 27 2024, 10:28 PM

Harbormaster completed remote builds in B57945: Diff 139161.May 27 2024, 10:28 PM

olce added a parent revision: D45391: sched: Internal priority ranges: Reduce kernel, increase timeshare.May 27 2024, 10:29 PM

olce mentioned this in D45393: runq/sched: Switch to 256 distinct queues and extend the timeshare range.May 27 2024, 10:36 PM

olce edited the summary of this revision. (Show Details)May 27 2024, 10:39 PM

Rebase.

Harbormaster completed remote builds in B59351: Diff 143036.Sep 6 2024, 1:53 PM

olce added a parent revision: D46567: sched_ule: Sanitize CPU's use and priority computations, and ticks storage.Sep 6 2024, 1:53 PM

olce removed a parent revision: D45391: sched: Internal priority ranges: Reduce kernel, increase timeshare.

This revision was not accepted when it landed; it landed in state Needs Review.Wed, Jun 18, 2:14 AM

Closed by commit rGa454ff6b0440: sched_4bsd: Move ESTCPULIM() after its macro dependencies (authored by olce). · Explain Why

This revision was automatically updated to reflect the committed changes.

olce added a commit: rGa454ff6b0440: sched_4bsd: Move ESTCPULIM() after its macro dependencies.

olce added a commit: rGeebc148f25c3: sched_4bsd: ESTCPULIM(): Allow any value in the timeshare range.

olce added a commit: rG51a4ae05abe6: sched_4bsd: Remove RQ_PPQ from ESTCPULIM()'s formula.Wed, Jun 18, 2:19 AM

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sys/

kern/

6 lines

Diff 157247

sys/kern/sched_4bsd.c

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