Re: [RFC PATCH 6/7] perf, x86: large PEBS interrupt threshold

From: Andi Kleen
Date: Wed May 28 2014 - 12:52:07 EST


> The only part I don't quite follow here is this:
> if (__test_and_set_bit(bit, (unsigned long *)&status))
> continue;
>
> Which seems to indicate the code is making sure each counter is
> processed only once. But it can only be processed once, if you have
> only one record. And if you have multiple, you want to be able to
> handle the same counter multiple times, at least once perf PEBS
> record. So I am a bit confused about this test.

Each PEBS record is only for a single counter overflow. So it
always should only be a single perf event.

-Andi
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