X-Recipient: archive-cygwin@delorie.com X-SWARE-Spam-Status: No, hits=-1.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_NONE,T_RP_MATCHES_RCVD,UNPARSEABLE_RELAY X-Spam-Check-By: sourceware.org Message-ID: <4F2C472C.1080403@t-online.de> Date: Fri, 03 Feb 2012 21:44:28 +0100 From: Christian Franke User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:7.0.1) Gecko/20110928 Firefox/7.0.1 SeaMonkey/2.4.1 MIME-Version: 1.0 To: cygwin@cygwin.com Subject: Re: Slow stat() on noacl mounts due to x permission check References: <4F2C2589.2000907@t-online.de> <20120203191349.GH30293@calimero.vinschen.de> In-Reply-To: <20120203191349.GH30293@calimero.vinschen.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Delivered-To: mailing list cygwin@cygwin.com Corinna Vinschen wrote: > On Feb 3 19:20, Christian Franke wrote: >> Cygwin stat() may be much slower on noacl mounts than on acl >> mounts.This is because on noacl mounts the x-permission bit is >> guessed by checking for "#!", ":" or "MZ" in the first bytes of the >> file. AFAIKS this is done for all files except *.exe, *.lnk and >> *.com. >> >> A real world testcase with 20120201 snapshot on a (C++/Java >> development) tree with ~52000 files in ~12000 dirs: >> >> . noacl acl >> find -size ... (after boot) 518s 51s >> find -size ... (disk cached) 13s 8s >> find -name ... (disk cached) 3s 3s (does not need stat()) >> >> Is it really needed to do the header check for each file? >> >> Would it break important use cases if the check is only done for >> files with typical script file extensions? >> For example: no extension, .sh, .csh, .pl, .py, ... >> >> Another more flexible solution would be a mount option to configure this. >> (xguess=0: no check; 1: some extensions only; 2: all files) > We already have the exec/notexec/cygexec mount options, see > http://cygwin.com/cygwin-ug-net/using.html#mount-table > > Somehow I misunderstood the notexec option. Sorry for the noise. Christian -- 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