From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755340AbbJ1C22 (ORCPT ); Tue, 27 Oct 2015 22:28:28 -0400 Received: from smtprelay0003.hostedemail.com ([216.40.44.3]:50442 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755323AbbJ1C20 (ORCPT ); Tue, 27 Oct 2015 22:28:26 -0400 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1183:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1539:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2907:3138:3139:3140:3141:3142:3352:3622:3865:3867:3868:3871:3872:3874:4362:5007:6261:7875:9040:10004:10226:10400:10848:10967:11232:11658:11914:12296:12517:12519:12740:13069:13311:13357:14096:14097:21063:21080:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:1,LUA_SUMMARY:none X-HE-Tag: pig19_2c417f9e86e2d X-Filterd-Recvd-Size: 1633 Date: Tue, 27 Oct 2015 22:28:16 -0400 From: Steven Rostedt To: Chunyan Zhang Cc: mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] tracing: Only benchmark the time tracepoints take if tracing is on Message-ID: <20151027222816.32454410@grimm.local.home> In-Reply-To: <1445947933-27955-1-git-send-email-zhang.chunyan@linaro.org> References: <1445947933-27955-1-git-send-email-zhang.chunyan@linaro.org> X-Mailer: Claws Mail 3.13.0 (GTK+ 2.24.28; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Oct 2015 20:12:13 +0800 Chunyan Zhang wrote: > There's no need to record the time tracepoints take when tracing is off. > This is because: > 1) We cannot see these records since ring_buffer record is off at that > moment. > 2) If tracing is off and benchmark tracepoint is enabled, the time > tracepoint takes is fewer than the same situation when tracing is on, > since the tracepoints need to be wrote into ring_buffer, it would > take more time. If turn on tracing at this moment, the average and > standard deviation cannot exactly present the time that tracepoints > take to write data into ring_buffer. > Thanks! I'll add this when I get back from traveling. -- Steve > Signed-off-by: Chunyan Zhang