[etherlab-users] failing dc-sync-check (and rtdm patch)

[George Broz]

Hello,

Yes - the application cycle (as far as I can tell)
should be synchronized to the return of rt_timer_read().

I've tried two methods:
(1) a regular Xenomai task using rt_task_wait_period() 
(after setup with rt_task_set_periodic()), and 

(2) a Xenomai task awoken on an interrupt/timeout using
rt_intr_wait() where the timeout period is calculated
using rt_timer_read() on entry/exit from rt_intr_wait().

The period of the real-time task is set for 250 micro-seconds.
Xenomai task latency is on average in the 1 to 4 micro-second 
range, sometimes seeing a datapoint in the 10 to 20 
micro-second range.


Best regards,
--George Broz
Moog, Inc. Industrial Group

-----<etherlab-users-bounces at etherlab.org> wrote: -----
To: <etherlab-users at etherlab.org>
From: Florian Pose 
Sent by: 
Date: 02/08/2012 12:40AM
Subject: Re: [etherlab-users] failing dc-sync-check (and rtdm patch)

Am 30.01.2012 21:33, schrieb George Broz:
> In Xenomai, I call rt_timer_read() which should return 
> nanoseconds since 1970. (The configuration for Xenomai has 
> CONFIG_XENO_OPT_TIMING_PERIODIC=n aka "tickless mode"). This 
> is supplied to _application_time(). master_sync_reference() 
> is called immediately after, and ecrt_domain_queue()
> and ecrt_master_send() very soon after that.

Does your application cycle run synchronized to the time source returned
by rt_timer_read(), i. e. how is your wakeup time programmed?

-- 
Viele Grüße,
Florian Pose

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