From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20513 invoked by alias); 19 Apr 2017 23:01:11 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 20494 invoked by uid 89); 19 Apr 2017 23:01:10 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,RP_MATCHES_RCVD,SPF_PASS autolearn=ham version=3.3.2 spammy=degree, delays X-HELO: sasl.smtp.pobox.com Received: from pb-smtp1.pobox.com (HELO sasl.smtp.pobox.com) (64.147.108.70) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Wed, 19 Apr 2017 23:01:09 +0000 Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id A68096999F for ; Wed, 19 Apr 2017 19:01:09 -0400 (EDT) Received: from pb-smtp1.nyi.icgroup.com (unknown [127.0.0.1]) by pb-smtp1.pobox.com (Postfix) with ESMTP id 9E9446999E for ; Wed, 19 Apr 2017 19:01:09 -0400 (EDT) Received: from [192.168.1.4] (unknown [76.215.41.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pb-smtp1.pobox.com (Postfix) with ESMTPSA id 0F93C6999D for ; Wed, 19 Apr 2017 19:01:08 -0400 (EDT) To: cygwin@cygwin.com From: Daniel Santos Subject: long I/O delays when strace is running Message-ID: Date: Thu, 20 Apr 2017 18:13:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Pobox-Relay-ID: 136BD92C-2554-11E7-9E70-E680B56B9B0B-06139138!pb-smtp1.pobox.com X-IsSubscribed: yes X-SW-Source: 2017-04/txt/msg00245.txt.bz2 Well I've solved one problem, but now I have another one. To try to understand why except is getting broken pipes (child processes are "going away"), I modified DejaGNU's /usr/bin/runtest so that it would strace each except process: -exec "$expectbin" $debug -- "$runpath"/runtest.exp $target ${1+"$@"} +exec strace --output=/tmp/runtest.$$.log --trace-children --mask=startup $expectbin $debug -- $runpath/runtest.exp $target ${1+"$@"} However, when I run make -kj8 check after this, Cygwin processes that do file I/O and even ps become very unresponsive and CPU utilization is low (not to say that DejaGNU is good at balancing the test load). If I hit ctrl-C on the make process, it won't exit for somewhere around 30 seconds. I am able to reproduce this to some degree with this simple snippet, although the delays aren't as long as doing the above: for ((i = 0; i < 64; ++i)); do strace --output=/tmp/sleep.$$.log --trace-children --mask=startup sleep 64; done Can anybody try this and see if they get delays when running ps -ef or some such? Thanks, Daniel -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple