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Subject: Re: [BUG] perf_events: ctx_flexible_sched_in()
From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: eranian@gmail.com, linux-kernel@vger.kernel.org, mingo@elte.hu,
       paulus@samba.org, davem@davemloft.net, fweisbec@gmail.com,
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Date: Mon, 01 Feb 2010 13:27:03 +0100
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On Mon, 2010-02-01 at 13:20 +0100, Stephane Eranian wrote:
> The function does not allow maximizing PMU usage because of
> the way can_add_hw is managed. Basically, as soon as a group
> fail to be scheduled in, then no other group can. I believe this
> is not optimum. You need to skip the group that fails and keep
> scanning the list. There may be other groups which can be
> scheduled.

Yeah, I saw that too, we need a new hw_ callback for that, or more
structured error values out of ->enable that distinguish between this
event won't fit and pmu full.