Re: [PATCH] change cpuacct usage percpu format

[KAMEZAWA Hiroyuki]

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'll update this patch.
Thanks,
-kame





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