From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23828 invoked by alias); 7 Apr 2010 19:10:43 -0000 Received: (qmail 23817 invoked by uid 22791); 7 Apr 2010 19:10:43 -0000 X-SWARE-Spam-Status: No, hits=-1.9 required=5.0 tests=BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from e2.ny.us.ibm.com (HELO e2.ny.us.ibm.com) (32.97.182.142) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 07 Apr 2010 19:10:37 +0000 Received: from d01relay06.pok.ibm.com (d01relay06.pok.ibm.com [9.56.227.116]) by e2.ny.us.ibm.com (8.14.3/8.13.1) with ESMTP id o37IxSNv032379 for ; Wed, 7 Apr 2010 14:59:28 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay06.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o37JAUWs663652 for ; Wed, 7 Apr 2010 15:10:30 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o37JAU0i014718 for ; Wed, 7 Apr 2010 15:10:30 -0400 Received: from [9.47.18.61] (w-jimk.beaverton.ibm.com [9.47.18.61]) by d01av04.pok.ibm.com (8.14.3/8.13.1/NCO v10.0 AVin) with ESMTP id o37JAT5M014687; Wed, 7 Apr 2010 15:10:29 -0400 Subject: Re: static user probe performance From: Jim Keniston To: "Frank Ch. Eigler" Cc: systemtap@sourceware.org In-Reply-To: References: <4BABACFE.60406@redhat.com> <4BB65994.5070906@redhat.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 07 Apr 2010 19:10:00 -0000 Message-ID: <1270667428.2893.178.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2010-q2/txt/msg00055.txt.bz2 On Wed, 2010-04-07 at 10:43 -0400, Frank Ch. Eigler wrote: > >> run with stap > >> [...] > >> elapsed time > >> volatile semaphore 1858.71 > >> no volatile no semaphore 1865.68 > >> volatile no semaphore 1873.07 > >> no volatile semaphore 1878.09 > > > > So for this particular microbenchmark, systemtap probing imposes a 30x > > slowdown, yikes. How many probe hits does this represent? > > From scox's later numbers, that's 192 million hits, for about 9 > us/hit, which seems rather high. Yes, it is high. Are you probing a multithreaded app? We have a known performance problem there: http://sourceware.org/bugzilla/show_bug.cgi?id=5660 Jim