From: Mathieu Desnoyers <compudj@krystal.dyndns.org>
To: Nicholas Miell <nmiell@comcast.net>
Cc: Martin Bligh <mbligh@google.com>,
"Frank Ch. Eigler" <fche@redhat.com>,
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
prasanna@in.ibm.com, Andrew Morton <akpm@osdl.org>,
Ingo Molnar <mingo@elte.hu>, Paul Mundt <lethal@linux-sh.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Jes Sorensen <jes@sgi.com>, Tom Zanussi <zanussi@us.ibm.com>,
Richard J Moore <richardj_moore@uk.ibm.com>,
Michel Dagenais <michel.dagenais@polymtl.ca>,
Christoph Hellwig <hch@infradead.org>,
Greg Kroah-Hartman <gregkh@suse.de>,
Thomas Gleixner <tglx@linutronix.de>,
William Cohen <wcohen@redhat.com>,
ltt-dev@shafik.org, systemtap@sources.redhat.com,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Karim Yaghmour <karim@opersys.com>,
Pavel Machek <pavel@suse.cz>, Joe Perches <joe@perches.com>,
"Randy.Dunlap" <rdunlap@xenotime.net>,
"Jose R. Santos" <jrs@us.ibm.com>
Subject: Re: Performance analysis of Linux Kernel Markers 0.20 for 2.6.17
Date: Sun, 01 Oct 2006 03:47:00 -0000 [thread overview]
Message-ID: <20061001034212.GB13527@Krystal> (raw)
In-Reply-To: <1159642933.2355.1.camel@entropy>
* Nicholas Miell (nmiell@comcast.net) wrote:
> On Sat, 2006-09-30 at 14:01 -0400, Mathieu Desnoyers wrote:
> > Hi,
> >
> > Following the huge discussion thread about tracing/static vs dynamic
> > instrumentation/markers, a consensus seems to emerge about the need for a
> > marker system in the Linux kernel. The main issues this mechanism addresses are:
> >
> > - Identify code important to runtime data collection/analysis tools in tree so
> > that it follows the code changes naturally.
> > - Be visually appealing to kernel developers.
> > - Have a very low impact on the system performance.
> > - Integrate in the standard kernel infrastructure : use C and loadable modules.
> >
> > The time has come for some performance measurements of the Linux Kernel Markers,
> > which follows. I attach a PDF with tables and charts which condense these
> > results.
>
> Has anyone done any performance measurements with the "regular function
> call replaced by a NOP" type of marker?
>
Here it is (on the same setup as the other tests : Pentium 4, 3 GHz) :
* Execute an empty loop
- Without marker
NR_LOOPS : 10000000
time delta (cycles): 15026497
cycles per loop : 1.50
- With 5 NOPs
NR_LOOPS : 100000
time delta (cycles): 300157
cycles per loop : 3.00
added cycles per loop for nops : 3.00-1.50 = 1.50
* Execute a loop of memcpy 4096 bytes
- Without marker
NR_LOOPS : 10000
time delta (cycles): 12981555
cycles per loop : 1298.16
- With 5 NOPs
NR_LOOPS : 10000
time delta (cycles): 12983925
cycles per loop : 1298.39
added cycles per loop for nops : 0.23
If we compare this approach to the jump-over-call markers (in cycles per loop) :
NOPs Jump over call generic Jump over call optimized
empty loop 1.50 1.17 2.50
memcpy 0.23 2.12 0.07
Mathieu
OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg
Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
next prev parent reply other threads:[~2006-10-01 3:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-09-30 18:02 Mathieu Desnoyers
[not found] ` <1159642933.2355.1.camel@entropy>
2006-10-01 3:47 ` Mathieu Desnoyers [this message]
[not found] ` <1159676382.2355.13.camel@entropy>
2006-10-01 15:44 ` Mathieu Desnoyers
[not found] ` <1159747060.2355.21.camel@entropy>
2006-10-02 0:18 ` Mathieu Desnoyers
2006-10-02 0:53 ` Nicholas Miell
2006-10-02 14:42 ` [UPDATE] " Mathieu Desnoyers
[not found] ` <45212F1E.3080409@us.ibm.com>
2006-10-02 15:44 ` Mathieu Desnoyers
[not found] ` <Pine.LNX.4.64.0610081223150.28503@twinlark.arctic.org>
2006-10-10 13:58 ` Mathieu Desnoyers
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