Re: [PATCH] change cpuacct usage percpu format

From: Balbir Singh
Date: Fri Feb 27 2009 - 02:02:14 EST


* KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-02-27 15:55:17]:

> On Fri, 27 Feb 2009 12:09:55 +0530
> Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
>
> > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-02-27 14:05:37]:
> >
> > > I'd like to change cpuacct.usage_percpu format before it's widely used.
> > > Current format is not easy to use in hardware with DR feature.
> > >
> > > ==
> > > cpuacct.usage_percpu shows per cpu usage information via cgroupfs.
> > > It shows all present cpus information and "whose information ?"
> > > is explained just by index of data implicitly.
> > >
> > > IIRC, there is physical cpu hotplug and it can remove
> > > cpus and change present map. Considering a software which records
> > > this information pediodically(like sar.), its better to show id of cpu
> > > in explict way.
> > >
> > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > > ---
> > > kernel/sched.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > Index: mmotm-2.6.29-Feb24/kernel/sched.c
> > > ===================================================================
> > > --- mmotm-2.6.29-Feb24.orig/kernel/sched.c
> > > +++ mmotm-2.6.29-Feb24/kernel/sched.c
> > > @@ -9719,7 +9719,7 @@ static int cpuacct_percpu_seq_read(struc
> > >
> > > for_each_present_cpu(i) {
> > > percpu = cpuacct_cpuusage_read(ca, i);
> > > - seq_printf(m, "%llu ", (unsigned long long) percpu);
> > > + seq_printf(m, "%d %llu\n", i, (unsigned long long) percpu);
> >
> > Seems like a reasonable change, but I wonder if " " should the
> > separator between the CPU and data, I wounder if we should use
> > cpu:usage_per_cpu.
>
> Ah, no strong reason for " ".
>
> Hmm, like this ?
> ==
> seq_printf(m, "%d: %llu\n", i, (unsigned long long) percpu);
> or
> seq_printf(m, "%d\t: %llu\n", i, (unsigned long long) percpu);
> ==
>
>

I'd like to see : and not space after it so something like

seq_printf(m, "%d:%llu\n", i, (unsigned long long) percpu);
--
Balbir
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