From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757579AbZHHBML (ORCPT ); Fri, 7 Aug 2009 21:12:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757556AbZHHBMK (ORCPT ); Fri, 7 Aug 2009 21:12:10 -0400 Received: from mx2.redhat.com ([66.187.237.31]:47794 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755112AbZHHBMJ (ORCPT ); Fri, 7 Aug 2009 21:12:09 -0400 Date: Fri, 7 Aug 2009 22:06:48 -0300 From: Arnaldo Carvalho de Melo To: Frederic Weisbecker Cc: Ingo Molnar , LKML , Peter Zijlstra , Mike Galbraith Subject: Re: [PATCH 1/4] perf tools: callchain: Warn only once in empty node detection Message-ID: <20090808010648.GL4339@ghostprotocols.net> References: <1249690585-9145-1-git-send-email-fweisbec@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1249690585-9145-1-git-send-email-fweisbec@gmail.com> X-Url: http://oops.ghostprotocols.net:81/blog User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Sat, Aug 08, 2009 at 02:16:22AM +0200, Frederic Weisbecker escreveu: > When we fill a new node that is found to be empty (sign of a bug), > we print a message each time that happens. Sometimes we reach thousands > of lines printed. > > Just warn only once in that case (and use stderr instead of stdout). Wouldn't this be better done with a macro so that the every message is print once instead of any fprintf_once message? I think it would even be nice to just use the same thing the kernel uses... WARN_ON_ONCE, and also using asm/bug.h, etc, just add it to tools/perf/util/include/asm, etc. That way one can even forget that this is not kernel programming... :-) - Arnaldo > Reported-by: Ingo Molnar > Signed-off-by: Frederic Weisbecker > Cc: Peter Zijlstra > Cc: Arnaldo Carvalho de Melo > Cc: Mike Galbraith > --- > tools/perf/util/callchain.c | 3 ++- > tools/perf/util/util.h | 3 +++ > tools/perf/util/wrapper.c | 16 ++++++++++++++++ > 3 files changed, 21 insertions(+), 1 deletions(-) > > diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c > index 98c5627..ce0c6d4 100644 > --- a/tools/perf/util/callchain.c > +++ b/tools/perf/util/callchain.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include "util.h" > > #include "callchain.h" > > @@ -203,7 +204,7 @@ fill_node(struct callchain_node *node, struct ip_callchain *chain, > } > node->val_nr = chain->nr - start; > if (!node->val_nr) > - printf("Warning: empty node in callchain tree\n"); > + fprintf_once(stderr, "Warning: empty node in callchain tree\n"); > } > > static void > diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h > index 68fe157..386ea40 100644 > --- a/tools/perf/util/util.h > +++ b/tools/perf/util/util.h > @@ -148,6 +148,9 @@ static inline const char *skip_prefix(const char *str, const char *prefix) > return strncmp(str, prefix, len) ? NULL : str + len; > } > > +extern int fprintf_once(FILE *fp, const char *fmt, ...) > + __attribute__((format (printf, 2, 3))); > + > #if defined(NO_MMAP) || defined(USE_WIN32_MMAP) > > #ifndef PROT_READ > diff --git a/tools/perf/util/wrapper.c b/tools/perf/util/wrapper.c > index 4574ac2..026c87c 100644 > --- a/tools/perf/util/wrapper.c > +++ b/tools/perf/util/wrapper.c > @@ -205,3 +205,19 @@ int xmkstemp(char *template) > die("Unable to create temporary file: %s", strerror(errno)); > return fd; > } > + > +int fprintf_once(FILE *fp, const char *fmt, ...) > +{ > + va_list args; > + int ret; > + static int once; > + > + if (once++) > + return 1; > + > + va_start(args, fmt); > + ret = vfprintf(fp, fmt, args); > + va_end(args); > + > + return ret; > +} > -- > 1.6.2.3