Re: [PATCH] change cpuacct usage percpu format

From: Balbir Singh
Date: Fri Feb 27 2009 - 01:40:24 EST


* 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.
--
Balbir
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