Re: [perfmon2] [PATCH] perf_events: add sampling period randomization support
Status: Beta
Brought to you by:
seranian
From: Peter Z. <pe...@in...> - 2010-03-02 09:13:43
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On Mon, 2010-03-01 at 22:07 -0800, er...@go... wrote: > This patch adds support for randomizing the sampling period. > Randomization is very useful to mitigate the bias that exists > with sampling. The random number generator does not need to > be sophisticated. This patch uses the builtin random32() > generator. > > The user activates randomization by setting the perf_event_attr.random > field to 1 and by passing a bitmask to control the range of variation > above the base period. Period will vary from period to period & mask. > Note that randomization is not available when a target interrupt rate > (freq) is enabled. > > The last used period can be collected using the PERF_SAMPLE_PERIOD flag > in sample_type. > > The patch has been tested on X86. There is also code for PowerPC but > I could not test it. I don't thikn we need to touch the arch code, we didn't need to for frequency driven sampling, so I don't see a reason to do so for randomization either. |