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Date: Thu, 06 Nov 2014 21:22:35 +0100
From: Philippe Gerum <rpm@xenomai.org>
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Subject: Re: [Xenomai] rt_task_sleep_until() miss release point?
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To: alberto.ozalla@cgglobal.com, "gilles.chanteperdrix@xenomai.org" <gilles.chanteperdrix@xenomai.org>
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On 11/06/2014 05:46 PM, ZIV-Alberto Ozalla Cantabrana wrote:
> Hi,
> 
> These are the simplest examples:
> There are no MSW for Test_Task.
> The goal is to increment counter_ms each millisecond.
> 
> Given that:
> 1000000 nanoseconds = 24000 tsc.
> 1 tsc = 41 ns
> 

Is rt_timer_ns2tsc(1000000) actually returning 24000 on your platform?

> void Test_Task(void *arg)
> {
>    rt_task_set_mode(0, 0, NULL);

This is useless and not recommended. A newly created task always starts
in primary mode.

>     while (1) {
> 
>             unsigned long long before = counter_ms;
>             usleep(1000000);    // 1 second.

Although this would rather cause higher count values, this non-rt main
using a non-rt sleep service won't give you an accurate delay for the
measurement.

-- 
Philippe.