Re: [PATCH] change cpuacct usage percpu format

[Balbir Singh <balbir@linux.vnet.ibm.com>]

* KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> [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@jp.fujitsu.com>
> ---
>  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