Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752516AbZCOFdp (ORCPT ); Sun, 15 Mar 2009 01:33:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751838AbZCOFdg (ORCPT ); Sun, 15 Mar 2009 01:33:36 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:47343 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750807AbZCOFdf (ORCPT ); Sun, 15 Mar 2009 01:33:35 -0400 Date: Sun, 15 Mar 2009 06:33:01 +0100 From: Ingo Molnar To: Mathieu Desnoyers Cc: Jason Baron , rostedt@goodmis.org, linux-kernel@vger.kernel.org, acme@ghostprotocols.net, fweisbec@gmail.com, fche@redhat.com, peterz@infradead.org Subject: Re: [Patch 2/2] tracepoints for softirq entry/exit - tracepoints Message-ID: <20090315053301.GC20949@elte.hu> References: <20090312183603.GC3352@redhat.com> <20090314025701.GC22526@Krystal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090314025701.GC22526@Krystal> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 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 Content-Length: 1983 Lines: 53 * Mathieu Desnoyers wrote: > * Jason Baron (jbaron@redhat.com) wrote: > > > > introduce softirq entry/exit tracepoints. These are useful for > > augmenting existing tracers, and to figure out softirq frequencies and > > timings. > > > > Signed-off-by: Jason Baron > > > > --- > > > > include/trace/irq_event_types.h | 12 ++++++++++++ > > kernel/softirq.c | 7 ++++++- > > 2 files changed, 18 insertions(+), 1 deletions(-) > > > > > > diff --git a/include/trace/irq_event_types.h b/include/trace/irq_event_types.h > > index 214bb92..38b4bdd 100644 > > --- a/include/trace/irq_event_types.h > > +++ b/include/trace/irq_event_types.h > > @@ -40,4 +40,16 @@ TRACE_EVENT(irq_handler_exit, > > __entry->irq, __entry->ret ? "handled" : "unhandled") > > ); > > > > +TRACE_FORMAT(irq_softirq_entry, > > + TP_PROTO(struct softirq_action *h, struct softirq_action *vec), > > + TP_ARGS(h, vec), > > + TP_FMT("softirq=%d action=%s", h - vec, softirq_to_name[h-vec]) > > + ); > > + > > +TRACE_FORMAT(irq_softirq_exit, > > + TP_PROTO(struct softirq_action *h, struct softirq_action *vec), > > + TP_ARGS(h, vec), > > + TP_FMT("softirq=%d action=%s", h - vec, softirq_to_name[h-vec]) > > The softirq tracepoints are a good idea indeed (I have similar > ones in the LTTng tree). My main concern is about the fact > that you output the softirq name in plain text to the trace > buffers. I would rather prefer to save only the softirq > (h-vec) into the trace and dump the mapping (h-vec) to name > only once, so we can save precious trace bytes. The right solution is to change this tracepoint to TRACE_EVENT() format. Jason, do you have time to do that? Ingo -- 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/