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-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a011e82e0079f0ea X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2003-08-10 12:17:36 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!logbridge.uoregon.edu!newshub.sdsu.edu!elnk-nf2-pas!newsfeed.earthlink.net!stamper.news.pas.earthlink.net!newsread3.news.pas.earthlink.net.POSTED!not-for-mail Message-ID: <3F369A4E.1050406@spam.com> From: Jeffrey Carter Organization: jrcarter commercial-at acm [period | full stop] org User-Agent: Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.0.0) Gecko/20020530 X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: Ravenscar - Multiple Protected Entries References: <3F35AFA7.1030905@spam.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Date: Sun, 10 Aug 2003 19:17:36 GMT NNTP-Posting-Host: 63.184.17.187 X-Complaints-To: abuse@earthlink.net X-Trace: newsread3.news.pas.earthlink.net 1060543056 63.184.17.187 (Sun, 10 Aug 2003 12:17:36 PDT) NNTP-Posting-Date: Sun, 10 Aug 2003 12:17:36 PDT Xref: archiver1.google.com comp.lang.ada:41308 Date: 2003-08-10T19:17:36+00:00 List-Id: Stephan Heinemann wrote: >>Suppose 2 tasks have the same priority, are blocked on 2 entries of a >>protected object, and both barriers become True at the same time. How do >>you determine which of the 2 tasks executes next? > > > The one which suspended first - FIFO_Within_Priorities. But which one > suspended first? ... FIFO_Within_Priorities has nothing to do with it. There are 2 queues, and each has only 1 task in it, so each task is at the head of its queue. Each task is next to execute when its respective barrier becomes True. And the language rules do not specify which task executes first. So it is non-deterministic which task will execute next. -- Jeff Carter "All citizens will be required to change their underwear every half hour. Underwear will be worn on the outside, so we can check." Bananas