From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D320DC2B9F4 for ; Mon, 28 Jun 2021 08:11:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9CFB3619F1 for ; Mon, 28 Jun 2021 08:11:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232421AbhF1IOT (ORCPT ); Mon, 28 Jun 2021 04:14:19 -0400 Received: from mail.monom.org ([188.138.9.77]:37530 "EHLO mail.monom.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230294AbhF1IOD (ORCPT ); Mon, 28 Jun 2021 04:14:03 -0400 Received: from mail.monom.org (localhost [127.0.0.1]) by filter.mynetwork.local (Postfix) with ESMTP id 00FBD50051C; Mon, 28 Jun 2021 10:11:36 +0200 (CEST) Received: from localhost (unknown [94.31.100.41]) by mail.monom.org (Postfix) with ESMTPSA id BBC2A500143; Mon, 28 Jun 2021 10:11:35 +0200 (CEST) Date: Mon, 28 Jun 2021 10:11:35 +0200 From: Daniel Wagner To: Mike Galbraith Cc: John Kacur , RT , lkml , Clark Williams , Daniel Wagner , Johnathan Schwender , Peter Xu Subject: Re: [ANNOUNCE] rt-tests-2.0 Message-ID: <20210628081135.l7yvya7iaygb23ye@beryllium.lan> References: <20210625160801.9283-1-jkacur@redhat.com> <549a4a5579068b9b1ca7741cb0f4aafbd04f4389.camel@gmx.de> <1c1966dd51ae6f8ddcd892cba485c332281fbd37.camel@gmx.de> <3d6a6c593eed6f5d59209ba2d8db29fadcc72ad7.camel@gmx.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3d6a6c593eed6f5d59209ba2d8db29fadcc72ad7.camel@gmx.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mike, On Sat, Jun 26, 2021 at 02:45:27PM +0200, Mike Galbraith wrote: > On Sat, 2021-06-26 at 13:47 +0200, Mike Galbraith wrote: > > On Sat, 2021-06-26 at 08:55 +0200, Mike Galbraith wrote: > > > On Fri, 2021-06-25 at 12:08 -0400, John Kacur wrote: > > > > I'm pleased to announce rt-tests-2.0 > > > > > > Greetings, > > > > > > cyclictest seems to have grown an mlock related regression. > > > > Ok, chores done, I did a quick bisect/confirm. I didn't go stare > > at rt_test_start() to ponder what the mlockall connection may be. > > Moving the call above "Get current time" stops it mucking things up. Thanks a lot for your excellent report. rt_test_start does static char ts_start[MAX_TS_SIZE]; static void get_timestamp(char *tsbuf) { struct timeval tv; struct tm *tm; time_t t; gettimeofday(&tv, NULL); t = tv.tv_sec; tm = localtime(&t); /* RFC 2822-compliant date format */ strftime(tsbuf, MAX_TS_SIZE, "%a, %d %b %Y %T %z", tm); } void rt_test_start(void) { get_timestamp(ts_start); } I'd say the tsbuf access is the one which triggers a pagefault. John, I would suggest to move the rt_test_start() into rt_init() and take the timestamp at the execution start (as my initial version was). I think the additional pain in slightly more correct start timestamp (which is also not defined what it actually means in this context) is just not worth the effort. Thanks, Daniel