From mboxrd@z Thu Jan  1 00:00:00 1970
From: douglas.santos@polymtl.ca (Douglas Santos)
Date: Wed, 17 Nov 2010 17:56:29 -0500
Subject: [ltt-dev] Benchmarks of kernel tracing options 2 (ftrace,
	lttng and perf)
In-Reply-To: <1290030106.30543.74.camel@gandalf.stny.rr.com>
References: <1290029498.4ce449ba1679d@www.imp.polymtl.ca>
	<1290030106.30543.74.camel@gandalf.stny.rr.com>
Message-ID: <1290034589.4ce45d9d7be28@www.imp.polymtl.ca>

Quoting Steven Rostedt <rostedt at goodmis.org>:

> On Wed, 2010-11-17 at 16:31 -0500, Douglas Santos wrote:
> > Hi all,
> >
> > This is a response to a benchmark, submitted a few weeks ago, comparing
> kernel
> > tracing options.
> > http://lkml.org/lkml/2010/10/28/422
> >
> > We followed the methodology described in the link bellow,
> > but using the shellscripts posted there to reproduce autotest scripts.
> > http://lkml.org/lkml/2010/10/28/261
> >
> > We disabled the extra syscall tracing on lttng, for a fair comparison.
> > http://lkml.org/lkml/2010/10/28/290
> >
> > Average results with tracing "on":
> >
> > lttng:  220 ns
> > ftrace: 260 ns
>
> Heh, so ftrace got worse with the new kernel?

The previous bench was doing tracing "on" minus "off"
average results. They also used autotest scripts, not sure if
it does exactly the same thing.

I'll check if we missed something.