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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,b16c9883f36bc904 X-Google-Attributes: gid103376,public From: "Thierry Lelegard" Subject: Re: WinNT ADA compilers comparison Date: 2000/07/22 Message-ID: <8lcgbi$gvb$1@front5.grolier.fr>#1/1 X-Deja-AN: 649501580 Content-Transfer-Encoding: 7bit References: <3976C68A.12386D00@cadwin.com> <8l7fff$9kb$1@front1.grolier.fr> <3A92E737.E690906A@free.fr> <3978041A.EB0F8FCE@cadwin.com> X-Priority: 3 Content-Type: text/plain; charset="iso-8859-1" X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2014.211 X-Trace: front5.grolier.fr 964281522 17387 213.44.50.188 (22 Jul 2000 15:58:42 GMT) Organization: Club-Internet (France) X-MSMail-Priority: Normal Mime-Version: 1.0 NNTP-Posting-Date: 22 Jul 2000 15:58:42 GMT Newsgroups: comp.lang.ada Date: 2000-07-22T15:58:42+00:00 List-Id: > From the user point of view, I think that reliability comes first Sure. Performance comes after reliablity. > More than that, increase performance by 5 doesn't mean a lot. > After a user action : > he will find not acceptable the difference between 1s and 5s > he will not care or even notice the difference between 1ms and 5ms > (And I saw some developpers spending days for the second improvement, while > not even care about the first ..., usually the user is not very happy) There are two different points here: 1. The way the application (source code) is written 2. The way the compiler generates the binary code. Spending days optimizing the less relevant part of an application is the first point. I agree that this is useless. But, on a code generator point a view, there is no difference in optimizing from 5s to 1s and from 5ms to 1ms. The first case is most of the time (roughly) a loop of 1000 iterations of the second case in the source code. The quality and speed of the generated code is an instrinsic quality of a compiler. To address the full range of applications, a compiler must make it right. Let me briefly describe two cases I experienced where it made all the difference: - Years ago, I spent two days optimizing a few ms in a matrix calculation. Why? It was in a Sonar software and the extra ms missed the next hit. - Currently, we sell software products to customers. These software process huge amount of data and we must produce new versions on a regular basis. Our customers have invested a lot of money in large computers which are consequently accurately sized for our software. If the generated code becomes poor, then the customers must invest in larger systems, which is not acceptable on a commercial point of view. So, yes, the performance of the generated code is not important for hobbyists, educational institutions, GUI software, desktop tools, etc. But, for commercial industrial software products, it is essential. > I know few developpers linking just once a day. > For us, the difference between 20s and 4mns for linking is more than > important (we actually saw that difference between some compilers for > same code and executable) I agree. But it is also true that many Ada tools (including compilers) are written in Ada. So, improving the compile time is simply a nice side effect of improving the generated code performance. BTW, I also noticed the same magnitude of difference between compilers, maybe we used the same two... -Thierry ________________________________________________________ Thierry Lelegard, Paris, France E-mail: lelegard@club-internet.fr