Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933002AbYARWtf (ORCPT ); Fri, 18 Jan 2008 17:49:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762987AbYARWt0 (ORCPT ); Fri, 18 Jan 2008 17:49:26 -0500 Received: from ms-smtp-05.nyroc.rr.com ([24.24.2.59]:60263 "EHLO ms-smtp-05.nyroc.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762736AbYARWtZ (ORCPT ); Fri, 18 Jan 2008 17:49:25 -0500 Date: Fri, 18 Jan 2008 17:49:19 -0500 (EST) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Mathieu Desnoyers cc: "Frank Ch. Eigler" , LKML , Ingo Molnar , Linus Torvalds , Andrew Morton , Peter Zijlstra , Christoph Hellwig , Gregory Haskins , Arnaldo Carvalho de Melo , Thomas Gleixner , Tim Bird , Sam Ravnborg , Steven Rostedt , Paul Mackerras , Daniel Walker Subject: Re: [RFC PATCH 16/22 -v2] add get_monotonic_cycles In-Reply-To: <20080118222637.GA30900@Krystal> Message-ID: References: <20080116145604.GB31329@Krystal> <20080116152838.GA970@Krystal> <20080116170011.GA3651@Krystal> <20080116201713.GA14336@Krystal> <20080117203740.GA24397@redhat.com> <20080118222637.GA30900@Krystal> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1532 Lines: 48 On Fri, 18 Jan 2008, Mathieu Desnoyers wrote: > > But I have not seen a lot of situations where that kind of glue-code was > needed, so I think it makes sense to keep markers simple to use and > efficient for the common case. > > Then, in this glue-code, we can put trace_mark() and calls to in-kernel > tracers. I'm almost done with the latency tracer work, and there are only a total of 6 hooks that I needed. - schedule context switch - try_to_wake_up - hard_irqs_off (which is already there for lockdep) - hard irqs on (also for lockdep) - lock_contention (already in for the lock contention code) - lock acquire (also in there for contention code) With the above, we could have this (if this is what I think you are recommending). For example in the context_switch case: trace_switch_to(prev, next); switch_to(prev, next, prev); and in sched.h I could have: static inline trace_switch_to(struct task_struct *prev, struct task_struct *next) { trace_mark(kernel_schedudule, "prev_pid %d next_pid %d prev_state %ld", prev->pid, next->pid, prev->pid); trace_context_switch(prev, next); } and have the trace_context_switch code be something that is turned on with the latency tracing utility (config option). That way production code can keep it off. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/