Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752487AbdF3TDU (ORCPT ); Fri, 30 Jun 2017 15:03:20 -0400 Received: from mail.kernel.org ([198.145.29.99]:44638 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751810AbdF3TDQ (ORCPT ); Fri, 30 Jun 2017 15:03:16 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 16BB222BC9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=rostedt@goodmis.org Date: Fri, 30 Jun 2017 15:03:13 -0400 From: Steven Rostedt To: Denys Vlasenko Cc: Masami Hiramatsu , linux-kselftest@vger.kernel.org, shuah@kernel.org, Ingo Molnar , Linux Kernel Mailing List Subject: Re: [PATCH] selftests: ftrace: Use md5sum to take less time of checking logs Message-ID: <20170630150313.146c863e@gandalf.local.home> In-Reply-To: References: <149855930170.10335.7114289594738299220.stgit@devbox> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; 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 Content-Length: 1538 Lines: 42 On Fri, 30 Jun 2017 20:50:45 +0200 Denys Vlasenko wrote: > On Tue, Jun 27, 2017 at 12:28 PM, Masami Hiramatsu wrote: > > Use md5sum so that it takes less time of checking > > trace logs update. Since busybox tail/cat takes too > > long time to read the trace log, this uses md5sum > > to check whether trace log is updated or not. > > > > Signed-off-by: Masami Hiramatsu > > --- > > .../test.d/ftrace/func_traceonoff_triggers.tc | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc > > index 9cf3852..7a9ab4f 100644 > > --- a/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc > > +++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_traceonoff_triggers.tc > > @@ -103,11 +103,11 @@ if [ $on != "0" ]; then > > fail "Tracing is not off" > > fi > > > > -line1=`cat trace | tail -1` > > +csum1=`md5sum trace` > > sleep $SLEEP_TIME > > -line2=`cat trace | tail -1` > > +csum2=`md5sum trace` > > If you replace that with "tail -1 in busybox will be used: > > off_t current = lseek(fd, 0, SEEK_END); The trace file is a kernel pseudo file that prevents lseek. Now what you could do is: cat trace > tempfile csum1=`tail -1