A Case Against (Most) Context Switches

By: Foo_ (foo.delete@this.nomail.com), May 18, 2021 1:58 am
Room: Moderated Discussions
Little Horn (sink.delete@this.example.net) on May 17, 2021 5:03 pm wrote:
> Thoughts?

It looks like they are hand-waving a lot of the difficulties.

- storing lots of thread state in registers in the CPU is supposed to be cheap (they also limit their size estimate to SSE3, conveniently ignoring AVX and AVX512)

- software scheduling still needs to happen in the not unlikely event that the total number of threads managed by software is larger than the number of HW theads (not unlikely, because they are advocating for the use of the blocking IO model, which requires one thread per on-going request)

- cache and TLB flushes will still happen... but, according to the authors, it's not a problem because it's not worse. Yet avoiding the *cost* of context switches was the entire motivation for their proposal

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TopicPosted ByDate
A Case Against (Most) Context SwitchesLittle Horn2021/05/17 05:03 PM
  A Case Against (Most) Context Switchesrwessel2021/05/17 06:55 PM
  A Case Against (Most) Context SwitchesFoo_2021/05/18 01:58 AM
    A Case Against (Most) Context SwitchesDoug S2021/05/18 08:45 AM
      A Case Against (Most) Context SwitchesKonrad Schwarz2021/05/19 07:35 AM
  A Case Against (Most) Context SwitchesEtienne Lorrain2021/05/18 03:11 AM
  A Case Against (Most) Context SwitchesAndrey2021/05/18 06:58 AM
  A Case Against (Most) Context Switchesgallier22021/05/18 08:41 AM
  A Case Against (Most) Context Switches---2021/05/18 09:00 AM
  A Case Against That Other PaperBrendan2021/05/18 12:37 PM
    A Case Against That Other PaperMark Roulo2021/05/18 03:32 PM
      A Case Against That Other PaperBrendan2021/05/18 11:05 PM
        A Case Against That Other PaperMark Roulo2021/05/19 01:09 PM
  A Case Against (Most) Context SwitchesRomain Dolbeau2021/05/19 04:05 AM
    A Case Against (Most) Context SwitchesBjörn Ragnar Björnsson2021/05/19 01:13 PM
      A Case Against ... authors show zero awareness of Cray-MTABjörn Ragnar Björnsson2021/05/19 06:18 PM
    Cray MTA avoided cachesPaul A. Clayton2021/05/20 06:36 AM
      Cray MTA avoided cachesdmcq2021/05/20 10:09 AM
        Cray MTA avoided cachesRayla2021/05/20 10:28 AM
      A LONG response to the paperPaul A. Clayton2021/05/22 06:15 AM
        A LONG response to the paperAdrian2021/05/22 09:18 AM
          Thank you for the note of appreciationPaul A. Clayton2021/05/24 05:06 AM
  A Case Against (Most) Context Switchesdmcq2021/05/19 01:47 PM
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