linux-kernel - Re: [PATCH] change cpuacct usage percpu format

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20090227155517.9283641b.kamezawa.hiroyu@jp.fujitsu.com>
Date:	Fri, 27 Feb 2009 15:55:17 +0900
From:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
To:	balbir@...ux.vnet.ibm.com
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	kenchen@...gle.com, "menage@...gle.com" <menage@...gle.com>,
	"lizf@...fujitsu.com" <lizf@...fujitsu.com>, mingo@...e.hu,
	"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
Subject: Re: [PATCH] change cpuacct usage percpu format

On Fri, 27 Feb 2009 12:09:55 +0530
Balbir Singh <balbir@...ux.vnet.ibm.com> wrote:

> * KAMEZAWA Hiroyuki <kamezawa.hiroyu@...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@...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.

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





--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/