Re: perf: bisected sampling bug in Linux 4.11-rc1

From: Vince Weaver
Date: Sat Jul 15 2017 - 23:07:28 EST

On Sat, 15 Jul 2017, Vince Weaver wrote:

> Although there is a separate issue also introduced in 4.11-rc1 that still
> fails a different testcase. I'm in the middle of bisecting that one and
> probably won't have the result of the bisect until Monday.

I went and bisected the other issue anyway. It wasn't in 4.11-rc1, but in
4.12-rc4. Yes, I have a test that triggered the
c1582c231ea041 perf/core: Drop kernel samples even though :u is specified

The test was actually losing 7% of its samples, so not just a single
sample here or there. The test had two events sampling, one at 100k and
one at 200k so I guess every other sample would have two samples
immediately back-to-back which must make it more likely to stray into the