linux-kernel - Re: [GIT PULL] cputime: Full dynticks task/cputime accounting v7

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Date:	Tue, 29 Jan 2013 16:12:10 +0100
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Li Zhong <zhong@...ux.vnet.ibm.com>,
	Namhyung Kim <namhyung.kim@....com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Sedat Dilek <sedat.dilek@...il.com>,
	Gleb Natapov <gleb@...hat.com>,
	Marcelo Tosatti <mtosatti@...hat.com>,
	Tony Luck <tony.luck@...el.com>,
	Fenghua Yu <fenghua.yu@...el.com>
Subject: Re: [GIT PULL] cputime: Full dynticks task/cputime accounting v7

2013/1/29 Steven Rostedt <rostedt@...dmis.org>:
> On Tue, 2013-01-29 at 04:29 +0100, Frederic Weisbecker wrote:
>> 2013/1/29 Steven Rostedt <rostedt@...dmis.org>:
>> > On Tue, 2013-01-29 at 03:39 +0100, Frederic Weisbecker wrote:
>> >
>> >> Please send me your kernelspin so I can test as well.
>> >
>> > http://rostedt.homelinux.com/private/kernelspin.c
>>
>> I can't reproduce your issue. I'm getting almost the same results with
>> vtime + force context tracking and tick based cputime.
>>
>
> Can you try my config.

Ok now with your config I can reproduce. Without context tracking
force (fallback to tick) I get a ratio of 1 / 8, with context tracking
force (vtime) I get 2 / 7.

I have set some cputime tracepoint and looked at the stacktrace. They
are sorted by weight, which is the amount of cputime accounted. I
can't find anything wrong on these. See attachment.

View attachment "trace-cputime.txt" of type "text/plain" (161212 bytes)