Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1715400

Re: [PATCH 1/2] sched/wait: Break up long wake list walk

From Andi Kleen <ak@linux.intel.com>
Newsgroups linux.kernel
Subject Re: [PATCH 1/2] sched/wait: Break up long wake list walk
Date 2017-08-18 22:00 +0200
Message-ID <ufVB0-89n-7@gated-at.bofh.it> (permalink)
References (5 earlier) <ufQKZ-55f-7@gated-at.bofh.it> <ufSMN-6pz-11@gated-at.bofh.it> <ufTzb-6V7-17@gated-at.bofh.it> <ufUEV-7yR-9@gated-at.bofh.it> <ufUYi-7Um-3@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

> which is hacky, but there's a rationale for it:
> 
>  (a) avoid the crazy long wait queues ;)
> 
>  (b) we know that migration is *supposed* to be CPU-bound (not IO
> bound), so yielding the CPU and retrying may just be the right thing
> to do.

So this would degenerate into a spin when the contention is with
other CPUs? 

But then if we guarantee that migration has flat latency curve
and no long tail it may be reasonable.

If the contention is with the local CPU it could cause some
unfairness (and in theory priority inheritance issues with local
CPU contenders?), but hopefully not too bad.

-Andi

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 1/2] sched/wait: Break up long wake list walk Tim Chen <tim.c.chen@linux.intel.com> - 2017-08-15 03:20 +0200
  Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-15 03:50 +0200
    Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-15 04:30 +0200
      Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-15 05:00 +0200
        Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-15 05:20 +0200
          Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-15 05:30 +0200
            Re: [PATCH 1/2] sched/wait: Break up long wake list walk Tim Chen <tim.c.chen@linux.intel.com> - 2017-08-15 21:10 +0200
              Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-15 21:50 +0200
              Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-15 21:50 +0200
            Re: [PATCH 1/2] sched/wait: Break up long wake list walk Davidlohr Bueso <dave@stgolabs.net> - 2017-08-16 00:50 +0200
              Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-16 01:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-16 02:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk ebiederm@xmission.com (Eric W. Biederman) - 2017-08-17 01:30 +0200
              Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-16 01:00 +0200
    RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-17 18:20 +0200
      Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-17 18:30 +0200
        RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-17 22:20 +0200
          Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-17 22:50 +0200
            Re: [PATCH 1/2] sched/wait: Break up long wake list walk Mel Gorman <mgorman@techsingularity.net> - 2017-08-18 14:30 +0200
              RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-18 16:30 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Mel Gorman <mgorman@techsingularity.net> - 2017-08-18 16:50 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Tim Chen <tim.c.chen@linux.intel.com> - 2017-08-18 18:40 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-18 18:50 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-18 19:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-18 19:50 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Mel Gorman <mgorman@techsingularity.net> - 2017-08-18 21:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-18 21:20 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-18 22:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-18 22:20 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Mel Gorman <mgorman@techsingularity.net> - 2017-08-21 20:40 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-21 21:00 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-22 19:30 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-22 20:20 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-22 20:30 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Peter Zijlstra <peterz@infradead.org> - 2017-08-22 21:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-22 21:20 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Peter Zijlstra <peterz@infradead.org> - 2017-08-22 21:10 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-22 21:40 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Christopher Lameter <cl@linux.com> - 2017-08-22 23:10 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-22 23:30 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-23 01:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-23 01:20 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-23 17:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-22 21:40 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-22 22:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-22 22:50 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-22 23:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Peter Zijlstra <peterz@infradead.org> - 2017-08-22 23:00 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-23 16:50 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Tim Chen <tim.c.chen@linux.intel.com> - 2017-08-23 18:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-23 20:20 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-23 23:00 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-24 01:40 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Tim Chen <tim.c.chen@linux.intel.com> - 2017-08-24 19:50 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-24 20:20 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Mel Gorman <mgorman@techsingularity.net> - 2017-08-24 22:50 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Mel Gorman <mgorman@techsingularity.net> - 2017-08-23 18:10 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Andi Kleen <ak@linux.intel.com> - 2017-08-18 22:10 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-18 22:40 +0200
                RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-18 22:30 +0200
                Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-18 22:40 +0200
              Re: [PATCH 1/2] sched/wait: Break up long wake list walk Linus Torvalds <torvalds@linux-foundation.org> - 2017-08-18 19:00 +0200
            RE: [PATCH 1/2] sched/wait: Break up long wake list walk "Liang, Kan" <kan.liang@intel.com> - 2017-08-18 15:10 +0200

csiph-web