Subject: Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch
From: Ingo Molnar (mingo_AT_elte.hu)
Date: Mon Jul 19 2004 - 14:59:52 EEST
* Andrea Arcangeli <andrea_AT_suse.de> wrote:
> As Ingo basically showed (and I agree), all current might_sleep seems
> suitable to be converted to cond_resched. I checked all them and
> there's none that seems to be called in a loop for no good reason. the
> ones in the semaphore are quite nice too since it's better to schedule
> right before taking the semaphore than after getting it. The one in
> the semaphore and in the copy-user are the only place where preempt
> seems to be lower overhead but in most other places a spinlock is
> being taken very near to the cond_resched.
yes. Btw., i'm not sure whether you've noticed but last week i've also
created a 'clean' variant of the patch. The latest version against -mm
is:
http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-clean-2.6.7-mm7-H4
this one doesnt have any of the debugging/development helpers and
switches. I have still made it a .config option. Note how minimal the
patch became this way.
Ingo
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