From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 112517 invoked by alias); 18 Dec 2015 15:06:57 -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 112505 invoked by uid 89); 18 Dec 2015 15:06:56 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.2 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=Emacs, badly X-HELO: mail-in-17.arcor-online.net Received: from mail-in-17.arcor-online.net (HELO mail-in-17.arcor-online.net) (151.189.21.57) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (CAMELLIA256-SHA encrypted) ESMTPS; Fri, 18 Dec 2015 15:06:54 +0000 Received: from mail-in-03-z2.arcor-online.net (mail-in-03-z2.arcor-online.net [151.189.8.15]) by mx.arcor.de (Postfix) with ESMTP id 3pMYSW1MyDzYMr for ; Fri, 18 Dec 2015 16:06:51 +0100 (CET) Received: from mail-in-05.arcor-online.net (mail-in-05.arcor-online.net [151.189.21.45]) by mail-in-03-z2.arcor-online.net (Postfix) with ESMTP id 55281563673 for ; Fri, 18 Dec 2015 16:06:50 +0100 (CET) X-DKIM: Sendmail DKIM Filter v2.8.2 mail-in-05.arcor-online.net 3pMYST5xR1z2xqp Received: from Gertrud (p54B7EC2A.dip0.t-ipconnect.de [84.183.236.42]) (Authenticated sender: stromeko@arcor.de) by mail-in-05.arcor-online.net (Postfix) with ESMTPSA id 3pMYST5xR1z2xqp for ; Fri, 18 Dec 2015 16:06:49 +0100 (CET) From: Achim Gratz To: cygwin@cygwin.com Subject: Re: Cygwin multithreading performance References: Date: Fri, 18 Dec 2015 15:06:00 -0000 In-Reply-To: (Kacper Michajlow's message of "Sat, 14 Nov 2015 01:24:18 +0100") Message-ID: <87bn9nhk3e.fsf@Rainer.invalid> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-SW-Source: 2015-12/txt/msg00207.txt.bz2 Kacper Michajlow writes: > 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%. I've been testing this again with my local copy of Emacs' Git repository and at least on this two-core system it works just fine (it was working fine on a four-core system earlier). The object count phase looks serialized and doesn't go over 50%, however a good deal of that is system time anyway, so I assume it's file access. The actual compression uses whatever CPU=C2=A0it can get, with the occasional spike in system time when it goes to disk (it's an SSD). Is your repo local or on some remote filesystem? Regards, Achim. --=20 +<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+ SD adaptation for Waldorf microQ V2.22R2: http://Synth.Stromeko.net/Downloads.html#WaldorfSDada -- 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