Messages in this thread | | | Date | Sun, 29 May 2011 12:54:00 -0400 (EDT) | From | Vince Weaver <> | Subject | Re: perf: regression with PERF_EVENT_IOC_REFRESH |
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On Sat, 28 May 2011, Peter Zijlstra wrote:
> On Fri, 2011-05-27 at 23:38 -0400, Vince Weaver wrote: > > on that note (and while trying to document exactly what the ioctls do) it > > seems that a PERF_EVENT_IOC_REFRESH with an argument of anything higher > > than one does not work on kernels 2.6.36 and newer. The behavior acts > > as if 1 was passed, even if you pass in, say, 3. > > Urgh, no that should definitely work. Thanks for the test-case, I'll > work on that (probably not until Monday though, but who knows). >
after a painfully long bisection, it turns out that this problem was in theory introduced by the following commit:
d57e34fdd60be7ffd0b1d86bfa1a553df86b7172
perf: Simplify the ring-buffer logic: make perf_buffer_alloc() do everything needed
I'll see if I can come up with a patch, but it's a bit non-obvious why this commit is affecting the REFRESH value at all.
Vince vweaver1@eecs.utk.edu
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