Messages in this thread | | | Date | Thu, 04 Dec 2008 23:52:38 -0800 (PST) | Subject | Re: [patch 0/3] [Announcement] Performance Counters for Linux | From | David Miller <> |
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From: Arjan van de Ven <arjan@infradead.org> Date: Thu, 4 Dec 2008 23:02:06 -0800
> On Fri, 5 Dec 2008 07:31:31 +0100 > Ingo Molnar <mingo@elte.hu> wrote: > > > Btw., i'm curious, why would we want to do that? It skews the results > > if the task continues executing and counters stop. To get the highest > > quality profiling output the counters should follow the true state of > > the task that is profiled - and events should be passed to the > > monitoring task asynchronously. The _events_ can contain precise > > coupled information > > - but the counters should continue. > > btw stopping the task on counter overflow is an issue for things that > want to self profile, like JITs
They can fork off a thread to do this.
No blocking on couter overflow leads to inaccurate results. This is a pretty fundamental aspect of perf counter usage.
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