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=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 10a146,7bdd56c6db71678c X-Google-Attributes: gid10a146,public X-Google-Thread: 103376,b4c0f0f8a3cf7068 X-Google-Attributes: gid103376,public From: "Dr Richard A. O'Keefe" Subject: Re: Hotspot. Dynamic compilers "better" than static one? Date: 1998/06/02 Message-ID: <35735C36.6ED7@atlas.otago.ac.nz>#1/1 X-Deja-AN: 358645867 Content-Transfer-Encoding: 7bit References: <6kocc1$d80@drn.newsguy.com> <6kpk0h$qmo$1@supernews.com> Mime-Version: 1.0 Reply-To: ok@atlas.otago.ac.nz Content-Type: text/plain; charset=us-ascii Organization: Department of Computer Science, University of Otago Newsgroups: comp.lang.java.programmer,comp.lang.ada Date: 1998-06-02T00:00:00+00:00 List-Id: Robert Dewar wrote: <> > Actually fewer production compilers than you might imagine actually use > this approach, though of course it has appeared in research compilers for > a long time. Sun's C, Pascal, and Fortran compilers for SPARC do this. Digital's compilers for the Alpha do this. The MIPS compilers have done this even longer. In fact, of the machines I have or could get accounts on here, the only ones that DON'T have 'production compilers' already installed that use profile-driven-feedback are Macs and PCs. What may be of more interest is that I have seen profile-driven feedback make a difference of 0-20%, with 0% actually being quite common, and I've had better performance using gcc -O6 (without feedback) on an Alpha than I've had from the Dec compiler _with_ feedback. So profile-driven feedback HAS BEEN SHIPPING FOR SEVERAL YEARS in production compilers from MIPS, Digital, and Sun, and that's just the ones I've used. But it's only one technique, and not always the most important.