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 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,7767a311e01e1cd X-Google-Attributes: gid103376,public X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news4.google.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.comcast.com!news.comcast.com.POSTED!not-for-mail NNTP-Posting-Date: Tue, 24 Oct 2006 22:54:23 -0500 Date: Tue, 24 Oct 2006 23:50:58 -0400 From: Jeffrey Creem User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: GNAT compiler switches and optimization References: <1161341264.471057.252750@h48g2000cwc.googlegroups.com> <9Qb_g.111857$aJ.65708@attbi_s21> <434o04-7g7.ln1@newserver.thecreems.com> <4539ce34$1_2@news.bluewin.ch> <453A532F.2070709@obry.net> <9kfq04-sgm.ln1@newserver.thecreems.com> <5vgs04-64f.ln1@newserver.thecreems.com> <453bc74e$0$19614$426a74cc@news.free.fr> <4jit04-0gq.ln1@newserver.thecreems.com> <453d1d36$0$25551$bf4948fe@news.tele2.nl> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Message-ID: <2h3314-gak.ln1@newserver.thecreems.com> NNTP-Posting-Host: 24.147.74.171 X-Trace: sv3-W6GoYrRHBujeowjqOaQjKSUHcdvuFbtqQKPj5oxosWrXbNnsmM7MwhrQSxcmZ1SBvrncoYn9QcIActG!SOJOWujXuK0EC8UZDyxWNkUC6CajMrW9arMGEyVcO7lTpsJKPoZrt+X6kDivjILz0/ofA1MQ0Iwk!40I= X-Complaints-To: abuse@comcast.net X-DMCA-Complaints-To: dmca@comcast.net X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.32 Xref: g2news2.google.com comp.lang.ada:7193 Date: 2006-10-24T23:50:58-04:00 List-Id: Jeffrey R. Carter wrote: > Jeffrey Creem wrote: > >> >> 2) Small changes to the original code that still meet the original >> structure and intent of the original code can move the run time up and >> down by at least 50% >> 3) The two task based version of the code is running more than 2x >> faster than the single task version on a 2 processor machine. Some of >> this is from the two tasks but looking at the assembly, another >> portion of it is related to #2 above in that the re-arrangement of >> the math allows the compiler to get less brain dead. > > > These seem quite odd to me. Perhaps whatever is causing this is also the > cause of the speedup I saw in the sequential case when the > multiplication is put in a procedure. > Ok, we are all probably tired of taking about this topic but I posted what I think will be the final write-up on this (until the bugzilla issue for it is resolved). http://gnuada.sourceforge.net/pmwiki.php/Main/Oct2006CLAGFORTRANComparison And I agree that the > 2x speedup for the two task version is not real. There are now other versions that are coded in a similar maner to the 2 task version but which are single threaded. The 2 task version runs almost exactly 2x faster (sometimes slightly slower) on my dual processor machine.