Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759092AbZCPNfR (ORCPT ); Mon, 16 Mar 2009 09:35:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753412AbZCPNfB (ORCPT ); Mon, 16 Mar 2009 09:35:01 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:49857 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752257AbZCPNfB (ORCPT ); Mon, 16 Mar 2009 09:35:01 -0400 Date: Mon, 16 Mar 2009 09:34:57 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Mathieu Desnoyers cc: Jason Baron , mingo@elte.hu, 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 In-Reply-To: <20090314025701.GC22526@Krystal> Message-ID: References: <20090312183603.GC3352@redhat.com> <20090314025701.GC22526@Krystal> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) 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: 2005 Lines: 52 On Fri, 13 Mar 2009, 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 TP_FMT is only used by those tracers that want to use it. Any tracer can still hook directly to the trace point and do what every they want. -- 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/