Re: perf_counters issue with self-sampling threads

[Peter Zijlstra]

On Mon, 2009-07-27 at 18:51 +0200, stephane eranian wrote:
> Hi,
> 
> I believe there is a problem with the current perf_counters (PCL)
> code for self-sampling threads. The problem is related to sample
> notifications via signal.
> 
> PCL (just like perfmon) is using SIGIO, an asynchronous signal,
> to notify user applications of the availability of data in the event
> buffer.
> 
> POSIX does not mandate that asynchronous signals be delivered
> to the thread in which they originated. Any thread in the process
> may process the signal, assuming it does not have the signal
> blocked.

Bugger, you're right. /me kicks POSIX again for creating these crazy ass
semantics.

I'll look at fixing this.

Thanks!

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