From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753189Ab0EFG3K (ORCPT ); Thu, 6 May 2010 02:29:10 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:35264 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751100Ab0EFG3H (ORCPT ); Thu, 6 May 2010 02:29:07 -0400 Date: Thu, 6 May 2010 08:28:55 +0200 From: Ingo Molnar To: Frederic Weisbecker Cc: Peter Zijlstra , Tejun Heo , efault@gmx.de, avi@redhat.com, paulus@samba.org, acme@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCHSET] sched,perf: unify tracers in sched and move perf on top of TP Message-ID: <20100506062855.GD1172@elte.hu> References: <1273050400.1642.229.camel@laptop> <4BE13B33.3030709@kernel.org> <1273053073.1642.235.camel@laptop> <4BE1406C.2000400@kernel.org> <1273059488.1642.245.camel@laptop> <4BE1648B.1080709@kernel.org> <20100505165532.GC14323@elte.hu> <1273083173.1642.250.camel@laptop> <1273083396.1642.251.camel@laptop> <20100505183000.GF6320@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100505183000.GF6320@nowhere> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Frederic Weisbecker wrote: > On Wed, May 05, 2010 at 08:16:36PM +0200, Peter Zijlstra wrote: > > On Wed, 2010-05-05 at 20:15 +0200, Peter Zijlstra wrote: > > > > > > Well, I'd much rather just see a direct call in the code than having to > > > reverse engineer wth hangs onto that _EVENT() junk. > > > > And again, I oppose mandating CONFIG_TRACEEVENT. > > > And me too. But you don't need CONFIG_EVENT_TRACING for that. TRACE_EVENT() > with !CONFIG_EVENT_TRACING only produces tracepoints if CONFIG_TRACEPOINTS. > > In fact, a first progress that would handle these compromizes would be to > have CONFIG_PERF_EVENT_SW. > > For now perf_event_task_sched_in and perf_event_task_sched_out can stay as > is because they are perf core utils. > > But all the rest (faults, migrations, etc..) could be tracepoints builtin > only if CONFIG_PERF_EVENT_SW. Which means CONFIG_PERF_EVENT_SW depends on > CONFIG_TRACEPOINTS. > > But nobody is forced to build CONFIG_PERF_EVENT_SW, breakpoints don't need > it. Yep. Also, most of the default distro kernels will have 3 sets of facilities: - preempt notifiers - tracepoints - sw events which is crazy. We can just standardize on using the tracepoint interface definition methods - they are properly typed, widespread and well-known enough to be perfect for this. ( They are also under intense optimization - the jump-tracepoints patch makes them probably even cheaper than preempt notifiers, in the off case. ) So lets get over this and consolidate our crazy hookery, and stand behind a single facility. I'm also all for slimming down the trace events facilities by not requiring the /debug/tracing/ bits to be present. Ingo