From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9562 invoked by alias); 1 Nov 2005 22:31:25 -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 9515 invoked by alias); 1 Nov 2005 22:31:23 -0000 Date: Tue, 01 Nov 2005 22:31:00 -0000 Message-ID: <20051101223123.9514.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug libfortran/21820] Really, really, horrible IO performance In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "Tobias dot Schlueter at physik dot uni-muenchen dot de" X-SW-Source: 2005-11/txt/msg00158.txt.bz2 List-Id: ------- Comment #16 from Tobias dot Schlueter at physik dot uni-muenchen dot de 2005-11-01 22:31 ------- Subject: Re: Really, really, horrible IO performance jblomqvi at cc dot hut dot fi wrote: > It depends on what you consider "really, really horrible IO performance". ;-) > Getting rid of mmap (the patch referred to above) improved performance by a > factor of 25, and I think before I made those measurements there were some > patches committed which made the mmap window bigger or somesuch, improving > performance compared to the situation when the bug was filed. So IMHO we have > made huge improvements. > > OTOH we still lose to ifort by a factor of 6 or so. The major reason is that > ifort does bulk transfers for implied do loops, while gfortran doesn't. > Changing the code to use array transfers makes gfortran only about a factor of > 1.5 slower than ifort. > > Personally, I think we can keep the bug around for reference, but change the > priority to "enhancement". We could probably close this as a duplicate of PR16339. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21820