From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22125 invoked by alias); 20 Nov 2009 21:53:24 -0000 Received: (qmail 22118 invoked by uid 22791); 20 Nov 2009 21:53:23 -0000 X-SWARE-Spam-Status: No, hits=-0.2 required=5.0 tests=AWL,BAYES_00,SPF_PASS,TVD_RCVD_IP X-Spam-Check-By: sourceware.org Received: from 207-172-212-176.c3-0.smr-ubr2.sbo-smr.ma.static.cable.rcn.com (HELO torpor.static.net) (207.172.212.176) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 20 Nov 2009 21:52:10 +0000 Received: from ita4fw1.itasoftware.com ([63.107.91.99] helo=jknight.internal.itasoftware.com) by torpor.static.net with esmtpa (Exim 4.69) (envelope-from ) id 1NBbOh-0007FN-UG for systemtap@sourceware.org; Fri, 20 Nov 2009 16:52:08 -0500 From: James Y Knight Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Dynamically enabling/disabling probe points from within stap script Date: Fri, 20 Nov 2009 21:53:00 -0000 Message-Id: <99F43110-6332-47AB-A399-21BCCFA48664@fuhm.net> To: systemtap@sourceware.org Mime-Version: 1.0 (Apple Message framework v1077) X-Spam-Score: -10.0 X-Spam-Report: ALL_TRUSTED=-10 X-IsSubscribed: yes 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: 2009-q4/txt/msg00622.txt.bz2 Is there any plan to allow the ability to dynamically and efficiently enabl= e and disable probes from within the systemtap script? I know you can do: probe process(...).mark("foo") if (whatever) {} but that isn't efficient: there's still substantial overhead at the mark po= int as long as 'stap' is running, even if you aren't interested in that pro= be currently. (The overhead appears to be about 3=B5s per mark hit, on my m= achine.) I saw some code in sdt.h about "semaphores", but that seems to just be an a= lternative to editing memory to insert a break instruction, and not a way t= o let the systemtap script temporarily disable probe points? Also nice would be a way to (efficiently!) say "run this probe every N time= s the location is hit". James