From: Andi Kleen <ak@suse.de>
To: discuss@x86-64.org
Cc: "Langsdorf, Mark" <mark.langsdorf@amd.com>,
"Gulam, Nagib" <nagib.gulam@amd.com>,
linux-kernel@vger.kernel.org, cpufreq@lists.linux.org.uk
Subject: Re: [discuss] Re: [PATCH] Allow all Opteron processors to change pstate at same time
Date: Wed, 26 Jul 2006 20:53:40 +0200 [thread overview]
Message-ID: <200607262053.40123.ak@suse.de> (raw)
In-Reply-To: <84EA05E2CA77634C82730353CBE3A84303218F09@SAUSEXMB1.amd.com>
> In contrast, the same machine running with TSC and standard
> PN! sees massive drift, upwards of an hour, within an hour.
Do you see the same drift when you lock date on a single CPU
with taskset?
> If the TSCnow! patch reduces measured drift down to a second
> a week, would you consider that acceptable?
No because even one second a week will break timing badly
over time.
I believe the only good solution unless hardware helps would
be to use per CPU TSC offsets as discussed earlier. Even that
is a bit risky because there can be still very small drifts,
but they should be limited by a clock tick error max and
might work out.
-Andi
next prev parent reply other threads:[~2006-07-26 18:59 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-06 20:31 [PATCH] Allow all Opteron processors to change pstate at same time Mark Langsdorf
2006-07-07 12:10 ` Andi Kleen
2006-07-07 17:36 ` [discuss] " Langsdorf, Mark
2006-07-10 12:45 ` Joachim Deguara
2006-07-10 13:02 ` Joachim Deguara
2006-07-11 12:55 ` Joachim Deguara
2006-07-11 13:07 ` Andi Kleen
2006-07-11 13:14 ` Arjan van de Ven
2006-07-11 16:15 ` Alan Cox
2006-07-11 16:01 ` Arjan van de Ven
2006-07-11 16:04 ` Andi Kleen
2006-07-11 13:31 ` Langsdorf, Mark
2006-07-11 13:34 ` Arjan van de Ven
2006-07-11 13:51 ` Andi Kleen
2006-07-11 13:14 ` [OT] Evolution use (was: Re: [discuss] Re: [PATCH] Allow all Opteron processors to change pstate at same time) Xavier Bestel
2006-07-12 14:06 ` [discuss] Re: [PATCH] Allow all Opteron processors to change pstate at same time Joachim Deguara
2006-07-12 14:54 ` Andi Kleen
2006-07-25 21:47 ` Langsdorf, Mark
2006-07-26 11:31 ` Joachim Deguara
2006-07-26 16:42 ` Langsdorf, Mark
2006-07-26 16:54 ` Andi Kleen
2006-07-26 18:34 ` Langsdorf, Mark
2006-07-26 18:53 ` Andi Kleen [this message]
-- strict thread matches above, loose matches on Subject: below --
2006-07-12 16:11 shin, jacob
2006-07-12 16:14 ` Langsdorf, Mark
2006-07-13 13:06 ` Pavel Machek
2006-07-13 14:32 ` Joachim Deguara
2006-07-16 1:56 ` Pavel Machek
2006-07-17 7:37 ` Joachim Deguara
2006-07-20 15:59 ` Pavel Machek
2006-07-13 13:37 Bhavana Nagendra
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