From: David Miller <davem@davemloft.net>
To: mingo@elte.hu
Cc: a.p.zijlstra@chello.nl, paulus@samba.org, tglx@linutronix.de,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
akpm@linux-foundation.org, eranian@googlemail.com,
dada1@cosmosbay.com, robert.richter@amd.com, arjan@infradead.org,
hpa@zytor.com, rostedt@goodmis.org
Subject: Re: [patch 0/3] [Announcement] Performance Counters for Linux
Date: Fri, 05 Dec 2008 00:49:22 -0800 (PST) [thread overview]
Message-ID: <20081205.004922.244597525.davem@davemloft.net> (raw)
In-Reply-To: <20081205084233.GE2030@elte.hu>
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 5 Dec 2008 09:42:33 +0100
> Please let me repeat: it's a _fundamental_ thesis of performance
> instrumentation to not disturb the monitored context. Your insistence on
> _stopping_ the monitored task breaks that fundamental axiom!
This is only a problem if you make your measurement quantums too
small.
Furthermore, there are multiple registers and states to update
atomically when a perf counter overflows. You're read/write thing
just doesn't cut it, especially for certain kinds of hardware.
It's really a utopian view of the world. :)
next prev parent reply other threads:[~2008-12-05 8:49 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-04 23:44 [patch 0/3] [Announcement] Performance Counters for Linux Thomas Gleixner
2008-12-04 23:44 ` [patch 1/3] performance counters: core code Thomas Gleixner
2008-12-05 10:55 ` Paul Mackerras
2008-12-05 11:20 ` Ingo Molnar
2008-12-04 23:44 ` [patch 2/3] performance counters: documentation Thomas Gleixner
2008-12-05 0:33 ` Paul Mackerras
2008-12-05 0:37 ` David Miller
2008-12-05 2:50 ` Arjan van de Ven
2008-12-05 3:26 ` David Miller
2008-12-05 2:33 ` Andi Kleen
2008-12-04 23:45 ` [patch 3/3] performance counters: x86 support Thomas Gleixner
2008-12-05 0:22 ` [patch 0/3] [Announcement] Performance Counters for Linux Paul Mackerras
2008-12-05 6:31 ` Ingo Molnar
2008-12-05 7:02 ` Arjan van de Ven
2008-12-05 7:52 ` David Miller
2008-12-05 7:03 ` Ingo Molnar
2008-12-05 7:03 ` Ingo Molnar
2008-12-05 7:16 ` Peter Zijlstra
2008-12-05 7:57 ` Paul Mackerras
2008-12-05 8:03 ` Peter Zijlstra
2008-12-05 8:07 ` David Miller
2008-12-05 8:11 ` Ingo Molnar
2008-12-05 8:17 ` David Miller
2008-12-05 8:24 ` Ingo Molnar
2008-12-05 8:27 ` David Miller
2008-12-05 8:42 ` Ingo Molnar
2008-12-05 8:49 ` David Miller [this message]
2008-12-05 12:13 ` Ingo Molnar
2008-12-05 12:13 ` Ingo Molnar
2008-12-05 12:39 ` Andi Kleen
2008-12-05 20:08 ` David Miller
2008-12-10 3:48 ` Paul Mundt
2008-12-10 4:42 ` Paul Mackerras
2008-12-10 8:43 ` Mikael Pettersson
2008-12-10 10:28 ` Andi Kleen
2008-12-10 10:23 ` Paul Mundt
2008-12-10 11:03 ` Andi Kleen
2008-12-10 11:03 ` Andi Kleen
2008-12-10 10:28 ` Andi Kleen
2008-12-05 15:00 ` Arjan van de Ven
2008-12-05 9:16 ` Paul Mackerras
2008-12-05 7:57 ` David Miller
2008-12-05 8:18 ` Ingo Molnar
2008-12-05 8:20 ` David Miller
2008-12-05 7:54 ` Paul Mackerras
2008-12-05 8:08 ` Ingo Molnar
2008-12-05 8:15 ` David Miller
2008-12-05 13:25 ` Ingo Molnar
2008-12-05 9:10 ` Paul Mackerras
2008-12-05 12:07 ` Ingo Molnar
2008-12-06 0:05 ` Paul Mackerras
2008-12-06 1:23 ` Mikael Pettersson
2008-12-06 12:34 ` Peter Zijlstra
2008-12-07 5:15 ` Paul Mackerras
2008-12-08 7:18 ` stephane eranian
2008-12-08 11:11 ` Ingo Molnar
2008-12-08 11:58 ` David Miller
2008-12-09 0:21 ` stephane eranian
2008-12-09 0:21 ` stephane eranian
2008-12-05 0:22 ` H. Peter Anvin
2008-12-05 0:43 ` Paul Mackerras
2008-12-05 1:12 ` David Miller
2008-12-05 6:10 ` Ingo Molnar
2008-12-05 7:50 ` David Miller
2008-12-05 9:34 ` Paul Mackerras
2008-12-05 10:41 ` Ingo Molnar
2008-12-05 10:05 ` Ingo Molnar
2008-12-05 3:30 ` Andrew Morton
2008-12-06 2:36 ` stephane eranian
2008-12-08 2:12 ` [perfmon2] [patch 0/3] [Announcement] Performance Counters forLinux Dan Terpstra
2008-12-10 16:27 ` [patch 0/3] [Announcement] Performance Counters for Linux Rob Fowler
2008-12-10 16:27 ` [perfmon2] " Rob Fowler
2008-12-10 17:11 ` Andi Kleen
2008-12-10 17:11 ` Andi Kleen
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