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Groups > linux.kernel > #1395667
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: sched: tweak select_idle_sibling to look for idle threads |
| Date | 2016-05-06 09:30 +0200 |
| Message-ID | <rvIn0-P0-33@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <runuj-5gi-33@gated-at.bofh.it> <runuk-5gi-47@gated-at.bofh.it> <ruogG-66V-17@gated-at.bofh.it> <ruJEu-1mn-9@gated-at.bofh.it> <ruKhb-1Y8-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, May 03, 2016 at 11:11:53AM -0400, Chris Mason wrote:
> # pick a single core, in my case cpus 0,20 are the same core
> # cpu_hog is any program that spins
> #
> taskset -c 20 cpu_hog &
>
> # schbench -p 4 means message passing mode with 4 byte messages (like
> # pipe test), no sleeps, just bouncing as fast as it can.
> #
> # make the scheduler choose between the sibling of the hog and cpu 1
> #
> taskset -c 0,1 schbench -p 4 -m 1 -t 1
>
> Current mainline will stuff both schbench threads onto CPU 1, leaving
> CPU 0 100% idle. My first patch with the minimal task_hot() checks
> would sometimes pick CPU 0. My second patch that just directly calls
> task_hot sticks to cpu1, which is ~3x faster than spreading it.
Ok, with the thing fixed, my current patch seems to DTRT. If I trace
sched_migrate_task() I get:
$ grep schbench trace
doit-schbench-2-4042 [004] d..3 144541.309747: sched_migrate_task: comm=doit-schbench-2 pid=4042 prio=120 orig_cpu=4 dest_cpu=4
doit-schbench-2-4042 [004] d..2 144541.309772: sched_migrate_task: comm=doit-schbench-2 pid=4043 prio=120 orig_cpu=4 dest_cpu=11
doit-schbench-2-4042 [004] d..3 144541.309855: sched_migrate_task: comm=doit-schbench-2 pid=4042 prio=120 orig_cpu=4 dest_cpu=4
doit-schbench-2-4042 [004] d..2 144541.309882: sched_migrate_task: comm=doit-schbench-2 pid=4044 prio=120 orig_cpu=4 dest_cpu=5
migration/11-77 [011] d..4 144541.309974: sched_migrate_task: comm=doit-schbench-2 pid=4043 prio=120 orig_cpu=11 dest_cpu=12
migration/5-40 [005] d..4 144541.310013: sched_migrate_task: comm=doit-schbench-2 pid=4044 prio=120 orig_cpu=5 dest_cpu=6
schbench-4044 [001] d..3 144541.310995: sched_migrate_task: comm=schbench pid=4044 prio=120 orig_cpu=1 dest_cpu=1
schbench-4044 [001] d..2 144541.310999: sched_migrate_task: comm=schbench pid=4045 prio=120 orig_cpu=1 dest_cpu=1
schbench-4045 [001] d..3 144541.311232: sched_migrate_task: comm=schbench pid=4045 prio=120 orig_cpu=1 dest_cpu=1
schbench-4045 [001] d..2 144541.311234: sched_migrate_task: comm=schbench pid=4046 prio=120 orig_cpu=1 dest_cpu=1
So the thing gets put on cpu1 and never leaves.
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Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-04-30 14:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-01 09:20 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-01 11:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-01 11:30 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-07 11:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-08 10:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 04:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 05:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 06:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 09:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 11:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 11:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-10 09:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-10 09:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-05-10 17:30 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-11 05:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-05-11 06:20 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-11 11:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <umgwanakikbuti@gmail.com> - 2016-05-11 12:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 06:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Yuyang Du <yuyang.du@intel.com> - 2016-05-09 06:20 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 10:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-02 17:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 17:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-02 17:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-03 16:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-03 17:20 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-04 12:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-04 17:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Matt Fleming <matt@codeblueprint.co.uk> - 2016-05-06 00:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-06 21:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-09 10:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-09 11:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-04 17:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-04 19:50 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-05 11:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-05 16:00 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-06 09:20 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Chris Mason <clm@fb.com> - 2016-05-06 19:30 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-06 09:30 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Mike Galbraith <mgalbraith@suse.de> - 2016-05-02 19:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 17:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Ingo Molnar <mingo@kernel.org> - 2016-05-02 18:10 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-03 13:40 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-03 20:30 +0200
Re: sched: tweak select_idle_sibling to look for idle threads Peter Zijlstra <peterz@infradead.org> - 2016-05-02 17:20 +0200
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