Re: [tip:perf/urgent] perf/x86: Enable raw event access to Inteloffcore events

[Stephane Eranian]

On Mon, Nov 21, 2011 at 10:42 PM, Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> On Mon, 2011-11-21 at 22:39 +0100, Stephane Eranian wrote:
>> To solve this problem (in the general case), you need to know which
>> counter is taken (or required)
>> by ALL pinned system-wide events across all CPUs. Once you've
>> constructed the bitmap, you can
>> use it as the basis (used_mask) to try and schedule the group events.
>>
> Its worse, you also need to consider all task-pinned events if you want
> to be complete. That's an even worse problem.
>
But that you know because by the time you do the simulation you already
know the task the events are attached to. You can get to the list of events
already attached to the task. Again this is a best effort, it could well be
that someone else attaches pinned task events just after the simulation.
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