From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755329Ab1ITJ0O (ORCPT ); Tue, 20 Sep 2011 05:26:14 -0400 Received: from merlin.infradead.org ([205.233.59.134]:56068 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754744Ab1ITJ0N convert rfc822-to-8bit (ORCPT ); Tue, 20 Sep 2011 05:26:13 -0400 Subject: Re: [PATCH 8/9] per-cgroup boot time From: Peter Zijlstra To: Glauber Costa 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 Date: Tue, 20 Sep 2011 11:25:46 +0200 In-Reply-To: <1316030695-19826-9-git-send-email-glommer@parallels.com> References: <1316030695-19826-1-git-send-email-glommer@parallels.com> <1316030695-19826-9-git-send-email-glommer@parallels.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.0.3- Message-ID: <1316510746.11841.18.camel@twins> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2011-09-14 at 17:04 -0300, Glauber Costa wrote: > Record the time in which the cgroup was created. This can be > used to provide a more accurate boottime information in > cpuacct.proc.stat. > > Signed-off-by: Glauber Costa > --- > kernel/sched.c | 8 +++++++- > 1 files changed, 7 insertions(+), 1 deletions(-) > > diff --git a/kernel/sched.c b/kernel/sched.c > index 4611c54..8f254d0 100644 > --- a/kernel/sched.c > +++ b/kernel/sched.c > @@ -9120,6 +9120,7 @@ struct cpuacct { > /* cpuusage holds pointer to a u64-type object on every cpu */ > u64 __percpu *cpuusage; > u64 __percpu *cpustat; > + struct timespec start_time; > }; > > struct cgroup_subsys cpuacct_subsys; > @@ -9172,6 +9173,8 @@ static struct cgroup_subsys_state *cpuacct_create( > acct[CPUACCT_STAT_IDLE] = kstat_cpu(i).cpustat.idle; > acct[CPUACCT_STAT_IOWAIT] = kstat_cpu(i).cpustat.iowait; > } > + > + get_monotonic_boottime(&ca->start_time); > return &ca->css; > > out_free_usage: > @@ -9316,13 +9319,16 @@ static int cpuacct_proc_stat(struct cgroup *cgrp, struct cftype *cft, > unsigned int per_softirq_sums[NR_SOFTIRQS] = {0}; > struct timespec boottime; > struct cpuacct *ca = cgroup_ca(cgrp); > + struct timespec ts; > u64 *cpustat; > > user = nice = system = idle = iowait = > irq = softirq = steal = cputime64_zero; > guest = guest_nice = cputime64_zero; > getboottime(&boottime); > - jif = boottime.tv_sec; > + 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.