From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <45ED99E9.2000105@domain.hid> Date: Tue, 06 Mar 2007 17:42:17 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 Subject: Re: [Xenomai-help] RTCAN and tsc References: <45ED84B8.3010307@domain.hid> <45ED8FC8.4090103@domain.hid> <45ED93AE.5050007@domain.hid> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 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: roland Tollenaar Cc: xenomai@xenomai.org roland Tollenaar wrote: > Hi > > I need to be educated a bit here if you don;t mind. > > arming up... > RTT| 00:00:01 (periodic user-mode task, 1000 us period, priority 99) > RTH|-----lat min|-----lat avg|-----lat max|-overrun|----lat best|---lat worst > RTD| 29.333| 29.333| 31.847| 0| 29.333| 31.847 > RTD| 29.333| 29.333| 35.199| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 33.523| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 32.685| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 34.361| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 33.523| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 33.523| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 34.361| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 32.685| 0| 29.333| 35.199 > RTD| 29.333| 29.333| 34.361| 0| 29.333| 35.199 > RTD| 29.333| 31.847| 201.142| 0| 29.333| 201.142 > RTD| 29.333| 59.504| 205.333| 0| 29.333| 205.333 > RTD| 29.333| 65.371| 201.142| 0| 29.333| 205.333 > RTD| 29.333| 68.723| 201.980| 0| 29.333| 205.333 > RTD| 29.333| 64.533| 201.142| 0| 29.333| 205.333 > RTD| 29.333| 65.371| 204.495| 0| 29.333| 205.333 > RTD| 29.333| 52.799| 201.142| 0| 29.333| 205.333 > RTD| 29.333| 65.371| 204.495| 0| 29.333| 205.333 > RTD| 29.333| 35.199| 201.142| 0| 29.333| 205.333 > RTD| 29.333| 29.333| 34.361| 0| 29.333| 205.333 > RTD| 29.333| 29.333| 33.523| 0| 29.333| 205.333 > ---|------------|------------|------------|--------|------------------------- > > > What you see above (up to where max latecy jumps to 200) is the > behavior while my application is running but the node (rotary encoder) > is not moving so not sending any position signals. The moment I start > turning the encoder shaft the jump takes place. > > What does output of latency mean? Is the above result simply stating > that I have a crappy hardware structure and will never be able to > achieve better latency or does it tell me there is something wrong > with my application? Enable the I-pipe tracer, recompile your kernel, set /proc/ipipe/trace/back_trace_points to a larger value, and run latency with the -f flag. Show us the contents of /proc/ipipe/trace/frozen, and we may be able to give you an answer. For more details on the I-pipe tracer, see: http://www.xenomai.org/index.php/I-pipe:Tracer -- Gilles Chanteperdrix