Date: Fri, 31 Mar 2006 20:15:48 +0200
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 (?)
Message-ID: <20060331181548.GA25053@elte.hu>
References: <4428E7B7.8040408@bull.net> <a36005b50603280702n2979d8ddh97484615ea9d4f3a@mail.gmail.com> <4429BCAC.80208@tmr.com> <20060329152643.GA13194@elte.hu> <442C3F3F.5050107@tmr.com> <20060331060155.GA21975@elte.hu> <442D41B1.1070005@tmr.com>
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* Bill Davidsen <davidsen@tmr.com> wrote:

> >What are you suggesting here, that the implementation of 
> >FUTEX_WAKE_OP is "ignoring inefficiencies"? Please explain why and 
> >what you would do differently to solve that inefficiency.
>
> I am suggesting that "There are no such situations anymore in an 
> optimal userlevel implementation" is not the right approach to the 
> original post. What I would do differently is to evaluate the original 
> suggestion to see if it would in fact be more efficient. [...]

that's what we did a year ago for a similar futex rescheduling 
inefficiency, and came up with the FUTEX_WAKE_OP solution, which is now 
part of the kernel and is used by glibc. But we are all ears for 
alternative suggestions.

	Ingo
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