Messages in this thread | | | Date | Mon, 13 Sep 2010 14:19:25 -0400 | From | Mathieu Desnoyers <> | Subject | Re: [RFC PATCH] check_preempt_tick should not compare vruntime with wall time |
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* Ingo Molnar (mingo@elte.hu) wrote: > > * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> wrote: > > > * Linus Torvalds (torvalds@linux-foundation.org) wrote: > > > On Mon, Sep 13, 2010 at 9:16 AM, Mathieu Desnoyers > > > <mathieu.desnoyers@efficios.com> wrote: > > > > > > > > OK, the long IRC discussions we just had convinced me that the current scheme > > > > takes things into account by adapting the granularity dynamically, but also got > > > > me to notice that check_preempt seems to compare vruntime with wall time, which > > > > is utterly incorrect. So maybe all my patch was doing was to expose this bug: > > > > > > Do you have latency numbers for this patch? > > > > Sure, see below, > > > > In addition to this patch, [...] > > Note, which is a NOP for your latency workload. > > > [...] I also used Peter's approach of reducing the minimum granularity > > Ok, that's the very first patch i sent yesterday morning - so we also > have my numbers that it reduces latencies. > > To move things along i'll apply it with your Reported-by and Acked-by > line, ok? > > We can also work on the other, more complex things after that, but first > lets make some progress on the latency front ...
Yep, that's fine with me.
Thanks!
Mathieu
> > Thanks, > > Ingo
-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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