From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 10.129.91.66 with SMTP id p63mr6585995ywb.63.1497648798771; Fri, 16 Jun 2017 14:33:18 -0700 (PDT) X-Received: by 10.157.46.21 with SMTP id q21mr406193otb.11.1497648798724; Fri, 16 Jun 2017 14:33:18 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!news.eternal-september.org!news.eternal-september.org!feeder.eternal-september.org!news.glorb.com!s24no693535qte.0!news-out.google.com!s132ni2588itb.0!nntp.google.com!f20no1150125itb.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Fri, 16 Jun 2017 14:33:18 -0700 (PDT) In-Reply-To: <649ddcbf-c898-4115-bbe5-59d678a94727@googlegroups.com> Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=5.51.16.193; posting-account=lzjH_AoAAABq5H4FTxZ1AkonVQLbXoxB NNTP-Posting-Host: 5.51.16.193 References: <65c5271c-33a1-4f36-977e-372af449d9c1@googlegroups.com> <44aa47f0-418a-4ede-b436-1937c3dbe065@googlegroups.com> <649ddcbf-c898-4115-bbe5-59d678a94727@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: Subject: Re: Poor performance with GNAT-GPL-2017 From: stephane.carrez@gmail.com Injection-Date: Fri, 16 Jun 2017 21:33:18 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: news.eternal-september.org comp.lang.ada:46965 Date: 2017-06-16T14:33:18-07:00 List-Id: Le jeudi 15 juin 2017 18:31:52 UTC+2, Charly a =C3=A9crit=C2=A0: >=20 > gnat-gpl-2016 -O > duration 3485 ms >=20 > gnat-gpl-2016 -O2 > duration 4713 ms >=20 > gnat-gpl-2016 -O3 > duration 2772 ms >=20 > gnat-gpl-2017 -O > duration 3375 ms >=20 > gnat-gpl-2017 -O2 > duration 4480 ms >=20 > gnat-gpl-2017 -O3 > duration 4823 ms >=20 > To summarize I draw two conclusions > This year optimization level -O is the best choice, > Try several optimization levels next year when gnat-gpl-2018 is out. The best choice is different for each program. As far as I'm concerned, I observe a 5% improvement in speed and 8% reduction in code size. The -O2 or -O3 give better performance for me. If you look at gcc bug list at https://gcc.gnu.org/bugzilla/ you will find some performance regressions for some very particular cases between gcc 4.9 and gcc 6.3. Fortunatly it does not affect the majority of programs. It might be interesting that you publish your program so that further investigations can be conducted. Stephane