From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4418 invoked by alias); 5 Jan 2006 16:26:31 -0000 Received: (qmail 4411 invoked by uid 22791); 5 Jan 2006 16:26:30 -0000 X-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (66.187.233.31) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 05 Jan 2006 16:26:30 +0000 Received: from int-mx1.corp.redhat.com (int-mx1.corp.redhat.com [172.16.52.254]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id k05GQPDc008301 for ; Thu, 5 Jan 2006 11:26:25 -0500 Received: from pobox.corp.redhat.com (pobox.corp.redhat.com [172.16.52.156]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id k05GQP102962; Thu, 5 Jan 2006 11:26:25 -0500 Received: from vpn50-30.rdu.redhat.com (vpn50-30.rdu.redhat.com [172.16.50.30]) by pobox.corp.redhat.com (8.12.8/8.12.8) with ESMTP id k05GQOor016984; Thu, 5 Jan 2006 11:26:24 -0500 Subject: Re: tapset feedback From: Martin Hunt To: Roland McGrath Cc: "systemtap@sources.redhat.com" In-Reply-To: <20060105111717.6ED55180B7C@magilla.sf.frob.com> References: <20060105111717.6ED55180B7C@magilla.sf.frob.com> Content-Type: text/plain Organization: Red Hat Inc Date: Thu, 05 Jan 2006 16:26:00 -0000 Message-Id: <1136478429.3853.14.camel@monkey2> Mime-Version: 1.0 X-Mailer: Evolution 2.0.2 (2.0.2-22) Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2006-q1/txt/msg00019.txt.bz2 On Thu, 2006-01-05 at 03:17 -0800, Roland McGrath wrote: > If a user script might want to use > kernel.syscall.foobar directly, then it will have to use % conditionals to > avoid those uses on kernels where the probe won't be defined because it > can't work; i.e., have to know the kernel versions to test for, This is exactly the ugly situation we now have. For every function that gets added/removed we have to know the exact kernel versions it happened in. And this means systemtap becomes less useful for nonstandard kernels because we won't know what options they were built with. > or perhaps > allow libraries/tapsets to export symbolic conditionals so a user can test > with %(have_foobar) in conditionals. That would have to be a runtime conditional. > The other choice is to define a special notion of "never" probes. So the idea here is that we define for each probe what to do if the probe does not match any current function. Isn't this kind of similar to my (perhaps poorly named) kernel.func probe point? Using kernel.func vs kernel.function means "do nothing if this probe point fails to match". What I REALLY would like to see is a way to say "here is a list of probe points. Set probes on as many as possible." Martin