From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Glauber Costa <glommer@parallels.com>
Cc: linux-kernel@vger.kernel.org, xemul@parallels.com,
paul@paulmenage.org, lizf@cn.fujitsu.com, daniel.lezcano@free.fr,
mingo@elte.hu, jbottomley@parallels.com
Subject: Re: [PATCH 8/9] per-cgroup boot time
Date: Tue, 20 Sep 2011 15:04:20 +0200 [thread overview]
Message-ID: <1316523860.13664.11.camel@twins> (raw)
In-Reply-To: <4E78890D.1000607@parallels.com>
On Tue, 2011-09-20 at 09:37 -0300, Glauber Costa wrote:
> >> + getboottime(&boottime);
> >> + ts = timespec_add(boottime, ca->start_time);
> >> + jif = ts.tv_sec;
> >>
> >> for_each_possible_cpu(i) {
> >> cpustat = per_cpu_ptr(ca->cpustat, i);
> >
> >
> > I'm confused, what does it do? You take a boot time timestamp at cgroup
> > creation, add that to all boot-time readings and print the result. How
> > does that make sense? Subtracting the start_time, maybe, that would make
> > the cgroup creation time 0, adding, not so much.
>
> Boot time represent at which times the machine was booted. In this
> context, at which time the container/cgroup was created. So it have to
> be an addition.... don't really understand your question
I think we're all properly confused now :-)
getboottime() gives a time since boot, right?
You take stamp at cgroup creation: say 50s after boot.
Then on usage you take a new getboottime() reading (which per definition
is > 50s) and add your 50s that you read previous. This results in the
cgroup having 50s of boot-time _MORE_ than the machine. Say you read at
123s, you then add your 50s timestamp, resulting in 173s to report.
If instead you did a subtraction: 123-50=73, you would have reported the
time since cgroup creation.
next prev parent reply other threads:[~2011-09-20 13:04 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-14 20:04 [PATCH 0/9] Per-cgroup /proc/stat Glauber Costa
2011-09-14 20:04 ` [PATCH 1/9] Remove parent field in cpuacct cgroup Glauber Costa
2011-09-19 16:03 ` Peter Zijlstra
2011-09-19 16:09 ` Glauber Costa
2011-09-19 16:19 ` Peter Zijlstra
2011-09-19 16:30 ` Glauber Costa
2011-09-19 16:39 ` Peter Zijlstra
2011-09-19 16:41 ` Glauber Costa
2011-09-19 18:40 ` Peter Zijlstra
2011-09-20 17:29 ` Srivatsa Vaddagiri
2011-09-22 15:11 ` Balbir Singh
2011-09-22 15:17 ` Peter Zijlstra
2011-09-23 8:09 ` Balbir Singh
2011-09-23 14:35 ` Peter Zijlstra
2011-09-23 15:45 ` Glauber Costa
2011-09-19 18:35 ` Peter Zijlstra
2011-09-19 18:38 ` Glauber Costa
2011-09-19 18:44 ` Peter Zijlstra
2011-09-19 19:14 ` Glauber Costa
2011-09-19 19:18 ` Peter Zijlstra
2011-09-19 19:19 ` Glauber Costa
2011-09-14 20:04 ` [PATCH 2/9] Make cpuacct fields per cpu variables Glauber Costa
2011-09-19 16:10 ` Peter Zijlstra
2011-09-14 20:04 ` [PATCH 3/9] Include nice values in cpuacct Glauber Costa
2011-09-19 16:19 ` Peter Zijlstra
2011-09-19 16:26 ` Glauber Costa
2011-09-19 18:36 ` Peter Zijlstra
2011-09-19 18:37 ` Glauber Costa
2011-09-14 20:04 ` [PATCH 4/9] Include irq and softirq fields " Glauber Costa
2011-09-19 18:38 ` Peter Zijlstra
2011-09-19 18:40 ` Glauber Costa
2011-09-14 20:04 ` [PATCH 5/9] Include guest " Glauber Costa
2011-09-14 20:04 ` [PATCH 6/9] Include idle and iowait " Glauber Costa
2011-09-20 9:21 ` Peter Zijlstra
2011-09-20 12:36 ` Glauber Costa
2011-09-20 12:58 ` Peter Zijlstra
2011-09-20 12:58 ` Glauber Costa
2011-09-20 13:05 ` Peter Zijlstra
2011-09-20 13:29 ` Glauber Costa
2011-09-14 20:04 ` [PATCH 7/9] Create cpuacct.proc.stat file Glauber Costa
2011-09-20 9:22 ` Peter Zijlstra
2011-09-20 12:22 ` Glauber Costa
2011-09-14 20:04 ` [PATCH 8/9] per-cgroup boot time Glauber Costa
2011-09-20 9:25 ` Peter Zijlstra
2011-09-20 12:37 ` Glauber Costa
2011-09-20 13:04 ` Peter Zijlstra [this message]
2011-09-20 13:06 ` Glauber Costa
2011-09-20 13:31 ` Peter Zijlstra
2011-09-14 20:04 ` [PATCH 9/9] Report steal time for cgroup Glauber Costa
2011-09-20 9:29 ` Peter Zijlstra
2011-09-14 20:13 ` [PATCH 0/9] Per-cgroup /proc/stat Peter Zijlstra
2011-09-14 20:20 ` Glauber Costa
2011-09-15 8:53 ` Peter Zijlstra
2011-09-14 20:23 ` Andi Kleen
2011-09-15 8:56 ` Peter Zijlstra
2011-09-19 23:07 ` Paul Turner
2011-09-20 8:33 ` Peter Zijlstra
2011-09-20 21:37 ` Glauber Costa
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