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=unavailable autolearn_force=no version=3.4.4 Path: border1.nntp.dca3.giganews.com!backlog3.nntp.dca3.giganews.com!border3.nntp.dca.giganews.com!border1.nntp.dca.giganews.com!border4.nntp.dca.giganews.com!border2.nntp.dca.giganews.com!nntp.giganews.com!usenet.blueworldhosting.com!feeder01.blueworldhosting.com!peer02.iad.highwinds-media.com!news.highwinds-media.com!feed-me.highwinds-media.com!post02.iad.highwinds-media.com!news.flashnewsgroups.com-b7.4zTQh5tI3A!not-for-mail From: Stephen Leake Newsgroups: comp.lang.ada Subject: Re: Raspberry Pi, Real-Time and Ada References: <5e8fad3a-94e6-4517-af54-db8b4146803e@googlegroups.com> <858uto3cj3.fsf@stephe-leake.org> Date: Fri, 07 Feb 2014 02:28:23 -0600 Message-ID: <85d2iz1g48.fsf@stephe-leake.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (windows-nt) Cancel-Lock: sha1:XhNwNHdT03xcjbufotnkcRLOlxo= MIME-Version: 1.0 Content-Type: text/plain X-Complaints-To: abuse@flashnewsgroups.com Organization: FlashNewsgroups.com X-Trace: 084ef52f4992ceef2f4a309743 X-Received-Bytes: 2331 X-Received-Body-CRC: 3754361522 X-Original-Bytes: 2573 Xref: number.nntp.dca.giganews.com comp.lang.ada:184696 Date: 2014-02-07T02:28:23-06:00 List-Id: "Rego, P." writes: > On Thursday, February 6, 2014 4:50:40 AM UTC-3, Stephen Leake wrote: >> You seem to be using "Real-Time" in some special technical way, as >> opposed to the general definition "meeting the application timing >> deadlines". > I really meant "meeting the application timing deadlines". Ok, good. What is your application? What are your timing requirements? >> Using the general definition, if your application has deadlines with >> tolerances on the order of 0.1 seconds, then the answer is clearly >> "yes". > Very slow, but based on what? I think you are asking: "How do you know the RPi can meet 0.1 second tolerances?" I've seen one running Emacs, and it responds well to keyboard commands. Humans notice delays longer than 0.1 seconds, so that's my metric. Why do you think 0.1 seconds is "slow"? If the application is flying a spacecraft to Jupiter, then 1 day is "fast" during the coast phase, when nothing much is happening. "fast" and "slow" are totally determined by the application. >> For tighter tolerances, you'd have to measure the actual performance, >> and possibly use an enhanced kernel as you discussed. > Measuring could be excelent. Do you know some tools that I could use > for measuring the RPi performance? That's heavily application dependent. If your application is some sort of control system, then it reads inputs, computes, and writes outputs. Using an oscilloscope, measure the time from an input signal to a related output signal. -- -- Stephe