Date: Tue, 21 Mar 2006 14:48:45 -0600
From: Dimitri Sivanich <sivanich@sgi.com>
To: Jack Steiner <steiner@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>, linux-kernel@vger.kernel.org,
       akpm@osdl.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: [RFC] - Move call to calc_load()
Message-ID: <20060321204845.GB26124@sgi.com>
References: <20060321203249.GA16182@sgi.com> <20060321203647.GA26135@elte.hu>
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On Tue, Mar 21, 2006 at 09:36:47PM +0100, Ingo Molnar wrote:
> * Jack Steiner <steiner@sgi.com> wrote:
> 
> > Here is the patch that I am proposing. This patch is incomplete 
> > because it addresses only the IA64 architecture. If this approach is 
> > acceptible, I'll update the patch to cover all architectures.
> > 
> > 	Signed-off-by: Jack Steiner <steiner@sgi.com>
> 
> i agree with your analysis - there is no reason calc_load() should be 
> under xtime_lock. I guess no-one noticed this so far because calc_load() 
> iterating over hundreds of CPUs isnt too common.

I tested this patch and it works well for eliminating latencies due to
contention for the xtime_lock.  Without the patch the latencies are
quite substantial at higher cpu counts.
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