From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15267 invoked by alias); 14 Nov 2015 00:24:23 -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 15257 invoked by uid 89); 14 Nov 2015 00:24:23 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=1.9 required=5.0 tests=AWL,BAYES_00,FREEMAIL_ENVFROM_END_DIGIT,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: mail-lb0-f180.google.com Received: from mail-lb0-f180.google.com (HELO mail-lb0-f180.google.com) (209.85.217.180) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Sat, 14 Nov 2015 00:24:22 +0000 Received: by lbbkw15 with SMTP id kw15so62855829lbb.0 for ; Fri, 13 Nov 2015 16:24:18 -0800 (PST) MIME-Version: 1.0 X-Received: by 10.112.172.138 with SMTP id bc10mr11478278lbc.74.1447460658497; Fri, 13 Nov 2015 16:24:18 -0800 (PST) Received: by 10.114.77.133 with HTTP; Fri, 13 Nov 2015 16:24:18 -0800 (PST) Date: Sat, 14 Nov 2015 00:24:00 -0000 Message-ID: Subject: Cygwin multithreading performance From: Kacper Michajlow To: cygwin@cygwin.com Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2015-11/txt/msg00208.txt.bz2 Hello, I recently noticed that Cygwin multithreading is very inefficient. I was repacking few git repositories and with Cygwin's git, it spawns threads but they are so badly synchronized that there is no speed gain over one thread and possible loose because of the overhead. On my machine I got 7-10% CPU usage while with git build with mingw easily uses 100%. You can find the code in question here https://github.com/git/git/blob/master/builtin/pack-objects.c#L1967-L2094 Do you have any suggestions? Is there any chance to get MT workloads improved in Cygwin? In present days it is really big problem in my opinion. Best Regard -- 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