From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <43F5F971.7050203@domain.hid> Date: Fri, 17 Feb 2006 17:27:29 +0100 From: Philippe Gerum MIME-Version: 1.0 Subject: Re: [Xenomai-help] no-brainer realtime issue References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Steven Seeger Cc: "xenomai@xenomai.org" Steven Seeger wrote: >>Yous seem to be running in periodic timing mode, with a default slice of 125 >>us. >>Which parameters are passed to rt_task_set_periodic() and >>rt_task_wait_period() in >>your sampling task? > > > I am confused why this matters? You said the latency test shows my realtime > does not work, so clearly the problem I have isn't specific to my code, but > rather to my system, right? > The latency figures obtained are totally braindamage, so either something weird is happening in 1) the real-time core, or 2) with the hw config selected, or 3) in the application. 1) is always possible, but you might also consider that early timer shots beyond two _milliseconds_ (-2293218 ns) would have been caught by a few other people on the list; this has not been the case yet. So considering a massive breakage in the real-time behaviour of that magnitude at this point of the investigation seems a bit premature. 2) Geode brings its own set of issues. SMI is one of them. Something may also go wrong when upgrading a kernel while reusing an old config file. Given your past answers, I now take for granted that it is not the case, but asking first is better. 3) v2.1 has changed a lot of things wrt v2.0, including the way some key configurations are made. Timing mode is one of those critical changes, and maybe one of those changes has had a negative impact in some unexpected way. Looking at the application to see what it requests to the real-time core and how it does it, is the usual way to start digging the issue. > Here is my call to rt_task_set_periodic: > > rt_task_set_periodic(&task, TM_NOW, rt_timer_ns2ticks(500000)); > Ok, I think we might be dealing with a timing mode issue. Could you try disabling CONFIG_XENO_OPT_TIMING_PERIODIC in your kernel config (Timing menu) and re-run the latency test? TIA, > I don't pass any parameters to rt_task_wait_period() > Yep, my mistake. > Steven > > -- Philippe.