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: a07f3367d7,cae92f92d6a1d4b1 X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!news3.google.com!proxad.net!feeder1-2.proxad.net!news.in2p3.fr!in2p3.fr!news.ecp.fr!news.jacob-sparre.dk!pnx.dk!not-for-mail From: "Randy Brukardt" Newsgroups: comp.lang.ada Subject: Re: Ada.Execution_Time Date: Mon, 27 Dec 2010 16:11:06 -0600 Organization: Jacob Sparre Andersen Message-ID: References: <4d05e737$0$6980$9b4e6d93@newsspool4.arcor-online.net> <1wmsukf0wglz3$.odnzonrpayly.dlg@40tude.net> <6n1c5myuf2uz$.10jl3ln7il3aq.dlg@40tude.net> <8n0mgnFv2sU1@mid.individual.net> <1n3o55xjdjr9t.1u33kb75y2jfl$.dlg@40tude.net> <8n1142Fto2U1@mid.individual.net> <1o5cbm4b1l20d$.19winbma6k5qw.dlg@40tude.net> <8n4mskF7mmU1@mid.individual.net> <8nm30fF7r9U1@mid.individual.net> NNTP-Posting-Host: static-69-95-181-76.mad.choiceone.net X-Trace: munin.nbi.dk 1293487868 21526 69.95.181.76 (27 Dec 2010 22:11:08 GMT) X-Complaints-To: news@jacob-sparre.dk NNTP-Posting-Date: Mon, 27 Dec 2010 22:11:08 +0000 (UTC) X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.5931 X-RFC2646: Format=Flowed; Response X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5931 Xref: g2news2.google.com comp.lang.ada:17144 Date: 2010-12-27T16:11:06-06:00 List-Id: "Niklas Holsti" wrote in message news:8nm30fF7r9U1@mid.individual.net... > Dmitry A. Kazakov wrote: >> On Sat, 18 Dec 2010 23:20:20 +0200, Niklas Holsti wrote: ... >> On a such platform the implementation would be as perverse as RM D.14 >> is. But the perversion is only because of the interpretation. > > Bah. I think that when RM D.14 says "time", it really means time. You > think it means something else, perhaps a CPU cycle count. I think the > burden of proof is on you. > > It seems evident to me that the text in D.14 must be interpreted using > the concepts in D.2.1, "The Task Dispatching Model", which clearly > specifies real-time points when a processor starts to execute a task and > stops executing a task. To me, and I believe to most readers of the RM, > the execution time of a task is the sum of these time slices, thus a > physical, real time. For the record, I agree more with Dmitry than Niklas here. At least the interpretation *I* had when this package was proposed was that it had only a slight relationship to real-time. My understanding was that it was intended to provide a window into whatever facilities the underlying system had for execution "time" counting. That had no defined relationship with what Ada calls "time". As usch, I think the name "execution time" is misleading, (and I recall some discussions about that in the ARG), but no one had a better name that made any sense at all. In particular, there is no requirement in the RM or anywhere else that these "times" sum to any particular answer. I don't quite see how there could be, unless you were going to require a tailored Ada target system (which is definitely not going to be a requirement). Perhaps the proposers (from the IRTAW meetings) had something else in mind, but if so, they communicated it very poorly. Randy.