All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ingo Molnar <mingo@elte.hu>
To: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Cc: Paul Mackerras <paulus@samba.org>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Mike Galbraith <efault@gmx.de>
Subject: Re: [PATCH] perf_counter: Make software counters work as per-cpu counters
Date: Tue, 10 Feb 2009 14:14:28 +0100	[thread overview]
Message-ID: <20090210131428.GA11571@elte.hu> (raw)
In-Reply-To: <1234232518.2604.335.camel@ymzhang>


* Zhang, Yanmin <yanmin_zhang@linux.intel.com> wrote:

> > > Signed-off-by: Paul Mackerras <paulus@samba.org>
> I tested it. The patch does fix the crash.

Great!

> > ok - i've applied your patch from email to allow Yanmin to test tip:master.
> Ingo,
> 
> Here is the patch to add system-wide collection for perfstat.c.
> 
> With the new parameter '-s', perfstat introduces very little overhead to benchmark 
> testing. [...]

Very nice. I've applied your patch to perfstat.c and have uploaded the new version 
to the usual place:

   http://redhat.com/~mingo/perfcounters/perfstat.c

> [...] If tracking performance data without '-s', sometimes perfstat has too much 
> impact on benchmark results, especially on netperf UDP-U-4k.

Yes - and we need to optimize that. It wont ever be zero-cost though, so -s makes 
sense independently of any need for optimizations. -s can also be used to measure 
the overhead of perfstat per task counters itself, via recursive inherited counters 
like this:

   perfstat -s perfstat ./workload

Thanks,

	Ingo

      reply	other threads:[~2009-02-10 13:14 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-09 11:42 [PATCH] perf_counter: Make software counters work as per-cpu counters Paul Mackerras
2009-02-09 11:48 ` Ingo Molnar
2009-02-10  2:21   ` Zhang, Yanmin
2009-02-10 13:14     ` Ingo Molnar [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20090210131428.GA11571@elte.hu \
    --to=mingo@elte.hu \
    --cc=efault@gmx.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=paulus@samba.org \
    --cc=tglx@linutronix.de \
    --cc=yanmin_zhang@linux.intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.