linux-kernel - Re: [PATCH] sched.c: Be a bit more conservative in SMP

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Message-Id: <200609070130.53995.vincent.plr@wanadoo.fr>
Date:	Thu, 7 Sep 2006 01:30:53 +0200
From:	Vincent Pelletier <vincent.plr@...adoo.fr>
To:	linux-kernel@...r.kernel.org
Cc:	mingo@...e.hu
Subject: Re: [PATCH] sched.c: Be a bit more conservative in SMP

I found one maybe-drawback to this change :
When runing n+1 process (n = number of cpu), one takes one cpu, the other 2 
share another cpu. And, because of this patch, all processes stay in their 
own cpu, so one always has 100% of cpu power, the 2 others get 50% each.
In current implementation, one of the 2 processes from the same cpu would 
migrate to the other cpu, and so on, somehow sharing cpu time among them.
Is it a feature or a side effect of current implementation ?

I'll do some tests soon to see which version gives better performance at a 
higher level than just process migration cost - if different at all.
-- 
Vincent Pelletier
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