Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection

From	Jacob Pan <jacob.jun.pan@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection
Date	2015-11-10 18:20 +0100
Message-ID	<qtkKm-7Wr-9@gated-at.bofh.it> (permalink)
References	(4 earlier) <qtiyS-6mw-29@gated-at.bofh.it> <qtk7E-7rz-9@gated-at.bofh.it> <qtk7E-7rz-7@gated-at.bofh.it> <qtkr1-7zd-19@gated-at.bofh.it> <qtkAF-7SL-1@gated-at.bofh.it>
Organization	OTC

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On Tue, 10 Nov 2015 18:00:10 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> > Different per CPU timer may intercept parameter changes at slightly
> > different time, so there is a race condition such that some CPUs may
> > catch the period change later by one period, which results in a
> > correct period change but at a different time, i.e. out of sync.  
> 
> Ah yes. So if the locking hurts I can come up with a lockless
> algorithm for this. Shouldn't be too hard.
Great! the current patch was designed to be lockless but a
little awkward. My idea was to have a common start time, then we don't
need to worry about CPUs out of sync, at most they will be off by one
period then catch up.

Thanks,

Jacob
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Thread

[RFC PATCH v2 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 01:30 +0100
  Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-10 14:30 +0100
    Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 15:10 +0100
      Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-10 16:00 +0100
        Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-10 17:40 +0100
          Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 18:00 +0100
            Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Peter Zijlstra <peterz@infradead.org> - 2015-11-10 18:10 +0100
              Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 18:20 +0100
        Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 17:40 +0100
    Re: [RFC PATCH v2 3/3] sched: introduce synchronized idle injection Jacob Pan <jacob.jun.pan@linux.intel.com> - 2015-11-10 19:50 +0100

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