From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752855AbbJBQ42 (ORCPT ); Fri, 2 Oct 2015 12:56:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43176 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751679AbbJBQ41 (ORCPT ); Fri, 2 Oct 2015 12:56:27 -0400 Date: Fri, 2 Oct 2015 18:56:24 +0200 From: Jiri Olsa To: kan.liang@intel.com Cc: acme@kernel.org, jolsa@kernel.org, namhyung@kernel.org, ak@linux.intel.com, linux-kernel@vger.kernel.org, Stephane Eranian Subject: Re: [PATCH 1/1] perf,stat: reduce interval-print to 10ms Message-ID: <20151002165624.GC1673@krava.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1443776674-42511-1-git-send-email-kan.liang@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 02, 2015 at 05:04:34AM -0400, kan.liang@intel.com wrote: > From: Kan Liang > SNIP > diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c > index a96fb5c..5ef88f7 100644 > --- a/tools/perf/builtin-stat.c > +++ b/tools/perf/builtin-stat.c > @@ -1179,7 +1179,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused) > OPT_STRING(0, "post", &post_cmd, "command", > "command to run after to the measured command"), > OPT_UINTEGER('I', "interval-print", &stat_config.interval, > - "print counts at regular interval in ms (>= 100)"), > + "print counts at regular interval in ms (>= 10)"), > OPT_SET_UINT(0, "per-socket", &stat_config.aggr_mode, > "aggregate counts per processor socket", AGGR_SOCKET), > OPT_SET_UINT(0, "per-core", &stat_config.aggr_mode, > @@ -1332,9 +1332,14 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused) > thread_map__read_comms(evsel_list->threads); > > if (interval && interval < 100) { > - pr_err("print interval must be >= 100ms\n"); > - parse_options_usage(stat_usage, options, "I", 1); > - goto out; > + if (interval < 10) { > + pr_err("print interval must be >= 10ms\n"); > + parse_options_usage(stat_usage, options, "I", 1); > + goto out; > + } else > + pr_warning("print interval < 100ms. " > + "The overhead percentage could be high in some cases. " > + "Please proceed with caution.\n"); with '-I' 10 this warning flies away quite fast ;-) I guess it's better than nothing, and I'm not sure about putting some sleep after that warning.. Acked-by: Jiri Olsa thanks, jirka