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Re: [Xen-devel] performance counters

To: "Keir Fraser" <keir@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] performance counters
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Date: Fri, 16 Mar 2007 08:17:46 +0000
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>>> Keir Fraser <keir@xxxxxxxxxxxxx> 15.03.07 16:03 >>>
>On 15/3/07 14:37, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:
>>> at least on architectures where we know the resulting incorrectness is not
>>> 'too bad' (that includes x86). Some of the shared counters are on hot paths.
>>> Alternatively we could make *all* counters per-cpu, even histogram counter
>>> arrays.
>> To me that would seem like the better alternative than dropping atomicity.
>It has the added benefit of avoiding cacheline bouncing.
>It just needs someone to implement this improvement. ;-)

I'll take care of this, but it may take me a few days to get to it. But I
also think there's no need for rush here.


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