From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 29398 invoked by alias); 12 Jan 2018 08:38:29 -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 29390 invoked by uid 89); 12 Jan 2018 08:38:27 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 spammy=eliot, moss, Moss, warranted X-HELO: mailsrv.cs.umass.edu Received: from mailsrv.cs.umass.edu (HELO mailsrv.cs.umass.edu) (128.119.240.136) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 12 Jan 2018 08:38:26 +0000 Received: from [150.203.106.8] (dhcp-liversidge8.anu.edu.au [150.203.106.8]) by mailsrv.cs.umass.edu (Postfix) with ESMTPSA id 26B8B401F605; Fri, 12 Jan 2018 03:38:23 -0500 (EST) Reply-To: moss@cs.umass.edu Subject: Re: calloc speed difference To: cygwin@cygwin.com References: From: Eliot Moss Message-ID: <1f0f6e79-57ef-1f02-f673-81826948adfc@cs.umass.edu> Date: Fri, 12 Jan 2018 08:38:00 -0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2018-01/txt/msg00106.txt.bz2 On 1/12/2018 2:19 AM, Lee wrote: > Why is the cygwin gcc calloc so much slower than the > i686-w64-mingw32-gcc calloc? Since your test repeatedly allocates and frees one chunk of size 100 Mb (ouch!) my guess is that the slow behavior is rooted in something to do with mmap. Perhaps Corinna or another internals expert can explain why large mmap requests would be a problem for cygwin -- and perhaps it is something that could be improved if the effort is warranted ... Eliot Moss -- 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