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, MSGID_RANDY autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,71b19e01eae3a390 X-Google-Attributes: gid103376,public From: dewar@gnat.com Subject: Re: delay until and GNAT - expand Date: 1999/05/08 Message-ID: <7h1e10$drg$1@nnrp1.deja.com>#1/1 X-Deja-AN: 475505685 References: <7gpukr$s82$1@nnrp1.dejanews.com> <7grkbb$cee$1@nnrp1.deja.com> <7grvka$lc5$1@nnrp1.deja.com> X-Http-Proxy: 1.0 x4.dejanews.com:80 (Squid/1.1.22) for client 205.232.38.10 Organization: Deja News - The Leader in Internet Discussion X-Article-Creation-Date: Sat May 08 13:25:54 1999 GMT Newsgroups: comp.lang.ada X-Http-User-Agent: Mozilla/4.5 [en] (WinNT; U) Date: 1999-05-08T00:00:00+00:00 List-Id: In article , rracine@draper.com (Roger Racine) wrote: > The implementation of "delay", given today's processor speeds, is pretty good. > I have recently single stepped my way (in assembly) through it, and while I > did not count the instructions, it had to be on the order of 100 instructions. > > So, given a good real-time operating system and a reasonably fast processor, a > reasonable upper limit would probably be close to 1 microsecond (conservative > estimate). > > I am surprised GNAT documentation does not have this, except that the number > will be different for every underlying OS. > > Roger Racine This is a highly misleading figure. The completion of a delay, in the sense that we are talking about, requires a preemptive context switch. To expect this to happen in 1 microsecond when running over an operating system like Unix, or even over a light real time executive is wildly optimistic. I am not sure what you are measuring, but it is quite wrong. We don't document upper limits for such things in the GNAT manual, because it is impractical to do so in almost all operating systems contexts, since we depend on the underlying OS, and this information is not available for the OS. Robert Dewar Ada Core Technologies -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own