From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gilles Chanteperdrix MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17618.14793.304543.952079@domain.hid> Date: Thu, 3 Aug 2006 20:00:41 +0200 Subject: Re: [Xenomai-help] testing interrupt latency In-Reply-To: <1154615459.9835.62.camel@domain.hid> References: <1154615459.9835.62.camel@domain.hid> List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Bart Jonkers Cc: xenomai@xenomai.org Bart Jonkers wrote: > Hey, > > I have written a small module to test the interrupt response time of > Xenomai to compare it with the time of Linux. > > I generate an interrupt on a GPIO pin and toggles another GPIO pin in > the interrupt service routine. (code below) > The time between the generated interrupt and the value change on the > GPIO pin is taken as interrupt response time. > > Everything works well, but I notice a strange behavior. > I thought that the interrupt response time of xenomai should be (as good > as) constant all the time. But I see that this is not the case. > > Did I do something wrong in my code or did I made a wrong assumption? What should be guaranteed by Xenomai is that the response time is bounded, not that it is constant. Of course, we make all we can to make the bound as small as possible, but each hardware has its limits. -- Gilles Chanteperdrix.