From: "Andi Kleen" <andi@firstfloor.org>
To: "Peter Zijlstra" <a.p.zijlstra@chello.nl>
Cc: "Andi Kleen" <andi@firstfloor.org>,
"Lin Ming" <ming.m.lin@intel.com>, "Ingo Molnar" <mingo@elte.hu>,
"Stephane Eranian" <eranian@google.com>,
"Arnaldo Carvalho de Melo" <acme@ghostprotocols.net>,
"linux-kernel" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/4] perf, x86: Add Intel Nehalem/Westmere uncore pmu
Date: Tue, 5 Jul 2011 18:01:36 +0200 [thread overview]
Message-ID: <cf54fbb6e05ab86a5c6029eda70012e4.squirrel@www.firstfloor.org> (raw)
In-Reply-To: <1309864954.3282.61.camel@twins>
>
>> But it's not strictly required I would say,
>> 44(?) bits are probably enough for near all use cases.
>
> 44bits is in the hours range for pure cycle counts, which is so-so. I
> bet you're going to be very annoyed when you find your counters are
> wrecked after your 5 hour test run finishes.
For these kinds of long running measurements you usually care about
ratios, not absolutes. Some infrequent wrapping should not substantially
change.
those.
-Andi
next prev parent reply other threads:[~2011-07-05 16:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-30 8:09 [PATCH 0/4] perf: Intel uncore pmu counting support Lin Ming
2011-06-30 8:09 ` [PATCH 1/4] perf, x86: Add Intel Nehalem/Westmere uncore pmu Lin Ming
2011-06-30 14:08 ` Peter Zijlstra
2011-07-01 6:05 ` Lin Ming
2011-06-30 16:58 ` Andi Kleen
2011-07-04 6:39 ` Lin Ming
2011-07-04 8:38 ` Peter Zijlstra
2011-07-04 21:57 ` Andi Kleen
2011-07-05 11:22 ` Peter Zijlstra
2011-07-05 12:48 ` Lin Ming
2011-07-05 12:56 ` Peter Zijlstra
2011-07-05 13:13 ` Lin Ming
2011-07-05 16:01 ` Andi Kleen [this message]
2011-07-06 9:35 ` Ingo Molnar
2011-06-30 8:09 ` [PATCH 2/4] perf, x86: Add Intel SandyBridge " Lin Ming
2011-06-30 22:09 ` Peter Zijlstra
2011-06-30 8:09 ` [PATCH 3/4] perf: Remove perf_event_attr::type check Lin Ming
2011-07-21 19:31 ` [tip:perf/core] " tip-bot for Lin Ming
2011-06-30 8:09 ` [PATCH 4/4] perf tool: Get PMU type id from sysfs Lin Ming
2011-06-30 12:10 ` [PATCH 0/4] perf: Intel uncore pmu counting support Stephane Eranian
2011-06-30 14:10 ` Peter Zijlstra
2011-06-30 16:27 ` Stephane Eranian
2011-07-01 3:17 ` Lin Ming
2011-07-01 10:49 ` Stephane Eranian
2011-07-01 12:23 ` Stephane Eranian
2011-07-01 12:28 ` Stephane Eranian
2011-07-04 6:03 ` Lin Ming
2011-07-01 5:49 ` Lin Ming
2011-07-01 11:08 ` Ingo Molnar
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