From mboxrd@z Thu Jan  1 00:00:00 1970
From: tromey@redhat.com (Tom Tromey)
Date: Wed, 16 Feb 2011 08:30:32 -0700
Subject: [ltt-dev] LTTng-UST vs SystemTap userspace tracing benchmarks
In-Reply-To: <4D5AA164.1050607@polymtl.ca> (Julien Desfossez's message of
	"Tue, 15 Feb 2011 10:53:08 -0500")
References: <4D5AA164.1050607@polymtl.ca>
Message-ID: <m37hd06lpj.fsf@fleche.redhat.com>

>>>>> "Julien" == Julien Desfossez <julien.desfossez at polymtl.ca> writes:

Julien> SystemTap 1.2-5 (from Debian package), hooking on DTrace user-space
Julien> static markup.

The sdt.h stuff has been rewritten at least once since then.  I'd
suggest trying the latest.  I think it probably won't matter for the
flight recorder mode, but it may matter for measuring overhead.

Julien> 0) Baseline : running the program without any instrumentation
Julien> 1) Flight recorder tracing comparison UST vs SystemTap

I'd be interested to also see the numbers when the probes are in place
in the source, but not enabled.  That is, what is the overhead of a
disabled probe?

When doing this with SystemTap it would be interesting to try twice:
once with a semaphore for each probe, and once without.

Tom