From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 17367 invoked by alias); 5 Jan 2006 09:05:41 -0000 Received: (qmail 17361 invoked by uid 22791); 5 Jan 2006 09:05:40 -0000 X-Spam-Status: No, hits=-1.8 required=5.0 tests=AWL,BAYES_00,SPF_FAIL X-Spam-Check-By: sourceware.org Received: from gateway.sf.frob.com (HELO gateway.sf.frob.com) (64.81.54.130) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 05 Jan 2006 09:05:39 +0000 Received: from magilla.sf.frob.com (magilla.sf.frob.com [198.49.250.228]) by gateway.sf.frob.com (Postfix) with ESMTP id EAF25357B; Thu, 5 Jan 2006 01:05:36 -0800 (PST) Received: by magilla.sf.frob.com (Postfix, from userid 5281) id BB3E9180B7C; Thu, 5 Jan 2006 01:05:36 -0800 (PST) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Martin Hunt Cc: "systemtap@sources.redhat.com" Subject: Re: tapset feedback In-Reply-To: Martin Hunt's message of Thursday, 5 January 2006 00:46:02 -0800 <1136450762.4001.1.camel@monkey2> X-Shopping-List: (1) Spacious momentous vagrant circumlocutions (2) Aerodynamic illustrious proclamations (3) Coniferous relaxers Message-Id: <20060105090536.BB3E9180B7C@magilla.sf.frob.com> Date: Thu, 05 Jan 2006 09:05:00 -0000 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/msg00010.txt.bz2 > One thing I would recommend is a conceptual split between "tapsets", > which export probe points and a system library, which would export > general-purpose safe functions. Why is this advantageous? The problems you've cited argue for some kind of name spaces or module system for systemtap functions and probes. But I don't off hand see how they lead you to conclude that distinguishing these two kinds of libraries (function libraries, and probe libraries, which some people like to call tapsets). > 2. I am not running 2.6.14, 2.6.9-20.ELsmp, or 2.6.9-24.ELsmp on any of > my machines, so I cannot use the syscalls tapset. I mention this not to > pick on that tapset, but to point out that we have a serious maintenance > problem created by the way we have implemented tapsets. Hopefully most of these kinds of troubles point to areas where we need to consider alternative implementation strategies that would be less kludgey and version-dependent in this way. > A. What if one of the functions matched does not exist in the current > kernel? Right now the compilation fails. What does that mean? A wildcard match will produce some set of actual probe points, and all of those will exist in the kernel that matches the debuginfo examined. Do you mean the situation when one of the patterns matches no functions at all? The differences in semantics you suggest for "func" are sensible things to want. I certainly don't think that one thing called "function" and one thing called "func" with slightly different semantics in these couple of ways is the right way to express it in any language I'd want to write in. Maybe someone can think of a better approach to satisfy these needs. Thanks, Roland