Re: [Xenomai-help] Problem getting the time with a kernel patched with xenomai

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Divi Oillo wrote:
> Hi, I post this message because I need a little help.

Hi,

> (...)
>                 gettimeofday(&timestamp_sav,NULL);
>                 nanosleep(&req,&req);
>                 gettimeofday(&timestamp,NULL);
> (...)

Note that your application does not benefit from any improvements made
by Xenomai, it is using Linux services.


> Why do I have +10010 µs or +10011 µs between each dating with my xenomai
> kernel and approximately +300 µs with my non-patched kernel?
> Thanks.

To obtain such results, you are probably running your test on an idle
system. But anyway, the problem is probably that the vanilla
configuration probably has high resolutions timers running, whereas the
Xenomai patched kernel has not.

Whether high resolution timers are enabled is both a question of
kernel-configuration (CONFIG_HIGHRES_TIMERS, CONFIG_X86_LOCAL_APIC,
CONFIG_HPET have an influence), and a question of run-time decisions.
You should find some hints in the kernel messages.

Regards.

-- 
					    Gilles.