From: Peter Zijlstra <peterz@infradead.org>
To: Stephane Eranian <eranian@google.com>
Cc: linux-kernel@vger.kernel.org, robert.richter@amd.com,
mingo@elte.hu, ming.m.lin@intel.com, ak@linux.intel.com
Subject: Re: [PATCH] perf_events: fix and improve x86 event scheduling
Date: Mon, 07 Nov 2011 15:56:10 +0100 [thread overview]
Message-ID: <1320677770.18053.51.camel@twins> (raw)
In-Reply-To: <CABPqkBREaQJk2gK7_Q5zUQhvV=EoxE1__ADw5VsiF-YPQNzeKw@mail.gmail.com>
On Mon, 2011-11-07 at 13:52 +0000, Stephane Eranian wrote:
> But given we limit the number of events to that of counters,
> we do have O(c^3).
Right, but SNB without HT gives you 8 GP counters, yielding a rather big
number. Suppose you're trying to fill it with 9 cycle events (1 for the
fixed purpose thingy), that'll end up being: 9^3 = 729 = big number.
(arguably adding 9 cycle counters is a tad retarded, but hey ;-)
It would be good to try and get it down to somewhere near 81 again,
although my brain isn't currently providing any sane ideas on how.
> As for the map_idx, it's there to track the position of each event in the
> initial event list. We shuffle events between constrained and unconstrained.
> By stashing the map_idx in the hw_perf_event struct we avoid having to
> pass around yet another array.
Yeah, I saw why you needed it..
next prev parent reply other threads:[~2011-11-07 14:57 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-07 11:01 [PATCH] perf_events: fix and improve x86 event scheduling Stephane Eranian
2011-11-07 11:55 ` Peter Zijlstra
2011-11-07 12:10 ` Peter Zijlstra
2011-11-07 13:52 ` Stephane Eranian
2011-11-07 14:56 ` Peter Zijlstra [this message]
2011-11-10 14:37 ` Peter Zijlstra
2011-11-10 15:09 ` Stephane Eranian
2011-11-10 16:41 ` Gleb Natapov
2011-11-10 16:59 ` Stephane Eranian
2011-11-10 17:13 ` Gleb Natapov
2011-11-10 16:59 ` Robert Richter
2011-11-10 18:31 ` Peter Zijlstra
2011-11-10 18:03 ` Robert Richter
2011-11-10 18:41 ` Peter Zijlstra
2011-11-10 18:52 ` Peter Zijlstra
2011-11-11 14:29 ` Robert Richter
2011-11-14 17:51 ` [PATCH v3 0/2] perf, x86: handle overlapping counters Robert Richter
2011-11-14 17:51 ` [PATCH v3 1/2] perf, x86: Implement event scheduler helper functions Robert Richter
2011-11-16 16:02 ` Peter Zijlstra
2011-11-16 19:23 ` Robert Richter
2011-11-14 17:51 ` [PATCH v3 2/2] perf, x86: Fix event scheduler for constraints with overlapping counters Robert Richter
2011-11-14 12:55 ` [PATCH] perf_events: fix and improve x86 event scheduling Stephane Eranian
2011-11-14 14:12 ` Peter Zijlstra
2011-11-14 14:26 ` Stephane Eranian
2011-11-14 16:00 ` Peter Zijlstra
2011-11-14 17:39 ` Stephane Eranian
2011-11-14 21:43 ` Peter Zijlstra
2011-11-16 10:28 ` Stephane Eranian
2011-11-14 22:16 ` Peter Zijlstra
2011-11-16 10:06 ` Stephane Eranian
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