Re: [patch] change futex_wait() to hrtimers

From: Thomas Gleixner
Date: Mon Mar 12 2007 - 07:13:35 EST


On Mon, 2007-03-12 at 12:02 +0100, Ingo Molnar wrote:
> > Well I did convert futex_wait to an absolute timeout based version in
> > the subsequent incremental patch. I think that is OK?
>
> it still has the rounding artifacts: using timer_list there is no way to
> do a precise long sleep based on many small sleeps.
>
> even if this means more work for you (i'm sorry about that!) i'm quite
> sure we should take Sebastien's hrtimers based implementation of
> futex_wait(), and use the nanosleep method to restart it. There's no
> point in further tweaking the imprecise approach: whenever some timeout
> needs to be restarted, it's a candidate for hrtimers.
>
> until then, glibc already handles timeouts and restarts it manually.

This also allows us to add a seperate absolute time bases futex op,
which allows to remove the conversion of abstime to reltime in glibc.

tglx


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