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

[Yan, Zheng]

On 07/10/2013 07:44 PM, Peter Zijlstra wrote:
> 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?
> 

yes, of course.

Regards
Yan, Zheng
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