From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31054 invoked by alias); 31 May 2005 16:48:51 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 30958 invoked by alias); 31 May 2005 16:48:37 -0000 Date: Tue, 31 May 2005 17:01:00 -0000 Message-ID: <20050531164837.30957.qmail@sourceware.org> From: "sgk at troutmask dot apl dot washington dot edu" To: gcc-bugs@gcc.gnu.org In-Reply-To: <20050530143227.21820.kargl@gcc.gnu.org> References: <20050530143227.21820.kargl@gcc.gnu.org> Reply-To: gcc-bugzilla@gcc.gnu.org Subject: [Bug libfortran/21820] Really, really, horrible IO performance X-Bugzilla-Reason: CC X-SW-Source: 2005-05/txt/msg04045.txt.bz2 List-Id: ------- Additional Comments From sgk at troutmask dot apl dot washington dot edu 2005-05-31 16:48 ------- Subject: Re: Really, really, horrible IO performance On Tue, May 31, 2005 at 07:38:41AM -0000, fxcoudert at gcc dot gnu dot org wrote: > First thing: I can reproduce the timings differences on my i386-linux, > with ext3 filesystem. > > Second thing: Steve, your patch truncates files, which is not correct! > Given the following modified testcase Yes, I know. See http://gcc.gnu.org/ml/fortran/2005-05/msg00420.html. Note, I played with various combination of mmap flags with no notice difference in performance. Also, I run FreeBSD with debugging kernel features, which causes a significant increase over non-debugging kernels. I've observed that if the file does not exist, the execution time is on order of 0.01 s. With a debugging kernel, I see execution times on the order of 70 s. With a non-debugging kernel, I see times on the order of 1 s. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21820