Re: [PATCH] perf: Update event buffer tail when overwriting oldevents

[Peter Zijlstra]

On Wed, Jul 10, 2013 at 07:37:43PM +0800, Yan, Zheng wrote:
> On 07/08/2013 08:15 PM, Peter Zijlstra wrote:
> > On Thu, Jun 06, 2013 at 01:58:06PM +0800, Yan, Zheng wrote:
> >> From: "Yan, Zheng" <zheng.z.yan@xxxxxxxxx>

> >>         before   overwrite mode      after   overwrite mode
> >> AVG      1000        999             1046        1044
> >> STDEV    19.4        19.5            17.1        17.9
> > 
> > OK, so I was sure I replied to this email; but apparently I didn't :/
> > 
> > So its still adding about 5% overhead to the regular case; this is sad.
> > 
> > What does something like the below do?
> > 
> 
> I re-test the patch on a different 32 core sandybridge-ep machine. the result is quite good.
> 
>        origin   origin overwrite       modified    modified overwrite
> AVG    1000      1044                   960        1006
> STDEV  39.0      26.0                   28.1       14.4

Nice! -- you did fix the snafu for the overwrite more before testing right?
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