From: Pavel Machek <pavel@ucw.cz>
To: kernel list <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@elte.hu>,
tglx@linutronix.de
Subject: nohz and strange sleep latencies
Date: Mon, 19 Nov 2007 21:31:52 +0100 [thread overview]
Message-ID: <20071119203152.GA1772@elf.ucw.cz> (raw)
Hi!
On unloaded x60 system, 2.6.24-rc3 (tainted-pavel-so if someone can
reproduce it, it would be helpful):
pavel@amd:~$ while true; do time sleep 0.01; done
0.00user 0.00system 0.01 (0m0.013s) elapsed 30.71%CPU
0.00user 0.00system 0.02 (0m0.024s) elapsed 8.36%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 15.53%CPU
0.00user 0.00system 0.02 (0m0.026s) elapsed 7.75%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 23.34%CPU
0.00user 0.00system 0.20 (0m0.207s) elapsed 1.45%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 15.59%CPU
0.00user 0.00system 0.23 (0m0.230s) elapsed 1.30%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 15.61%CPU
0.00user 0.00system 0.20 (0m0.201s) elapsed 1.48%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 15.50%CPU
0.00user 0.00system 0.19 (0m0.190s) elapsed 1.05%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 23.37%CPU
0.00user 0.00system 0.04 (0m0.049s) elapsed 4.09%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 23.35%CPU
0.00user 0.00system 0.01 (0m0.017s) elapsed 11.89%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 23.38%CPU
0.00user 0.00system 0.08 (0m0.081s) elapsed 3.71%CPU
0.00user 0.00system 0.01 (0m0.013s) elapsed 23.33%CPU
0.00user 0.00system 0.01 (0m0.019s) elapsed 15.92%CPU
nohz=off helps a lot. while true; do time sleep 0.0; done does not
have unexpected latencies.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next reply other threads:[~2007-11-19 20:35 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-19 20:31 Pavel Machek [this message]
2007-11-19 20:55 ` nohz and strange sleep latencies Ingo Molnar
2007-11-19 21:11 ` Pavel Machek
2007-11-20 8:57 ` Ingo Molnar
2007-11-20 9:05 ` Ingo Molnar
2007-11-20 10:54 ` Pavel Machek
2007-11-20 20:54 ` Ingo Molnar
2007-11-20 22:48 ` Thomas Gleixner
2007-11-20 22:52 ` Ingo Molnar
2007-11-22 10:09 ` Pavel Machek
2007-11-22 18:51 ` Pavel Machek
2007-11-22 18:52 ` Pavel Machek
2007-11-22 20:29 ` Thomas Gleixner
2007-11-23 12:22 ` Pavel Machek
2007-11-24 22:29 ` Pavel Machek
2007-11-24 22:40 ` Pavel Machek
2007-11-24 23:29 ` Rafael J. Wysocki
2007-11-24 23:35 ` Rafael J. Wysocki
2007-11-25 21:51 ` Thomas Gleixner
2007-11-25 20:25 ` [patch] " Pavel Machek
2007-11-25 21:42 ` Thomas Gleixner
2007-11-26 11:54 ` Pavel Machek
2007-11-20 9:44 ` Thomas Gleixner
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