From: Ingo Molnar <mingo@elte.hu>
To: Bill Davidsen <davidsen@tmr.com>
Cc: Ulrich Drepper <drepper@gmail.com>,
linux-kernel@vger.kernel.org, jakub@redhat.com
Subject: Re: [PATCH] 2.6.16 - futex: small optimization (?)
Date: Wed, 29 Mar 2006 17:26:43 +0200 [thread overview]
Message-ID: <20060329152643.GA13194@elte.hu> (raw)
In-Reply-To: <4429BCAC.80208@tmr.com>
* Bill Davidsen <davidsen@tmr.com> wrote:
> Ulrich Drepper wrote:
> >On 3/27/06, Pierre PEIFFER <pierre.peiffer@bull.net> wrote:
> >>I found a (optimization ?) problem in the futexes, during a futex_wake,
> >> if the waiter has a higher priority than the waker.
> >
> >There are no such situations anymore in an optimal userlevel
> >implementation. The last problem (in pthread_cond_signal) was fixed
> >by the addition of FUTEX_WAKE_OP. The userlevel code you're looking
> >at is simply not optimized for the modern kernels.
>
> What are you suggesting here, that the kernel can be inefficient as
> long as the user has a way to program around it?
What are you suggesting here, that FUTEX_WAKE_UP is a "user way to
program around" an inefficiency? If yes then please explain to me why
and what you would do differently.
Ingo
next prev parent reply other threads:[~2006-03-29 15:29 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-03-28 7:37 Pierre PEIFFER
2006-03-28 10:05 ` Eric Dumazet
2006-03-28 15:02 ` Ulrich Drepper
2006-03-28 22:46 ` Bill Davidsen
2006-03-29 15:26 ` Ingo Molnar [this message]
2006-03-30 20:27 ` Bill Davidsen
2006-03-31 6:01 ` Ingo Molnar
2006-03-31 14:50 ` Bill Davidsen
2006-03-31 18:15 ` Ingo Molnar
2006-03-29 13:18 ` Pierre PEIFFER
2006-03-29 15:26 ` Eric Dumazet
2006-03-30 14:51 ` Pierre PEIFFER
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