Re: [Xenomai-help] cyclictest gives out segmentation fault with xenomai 2.5.2 in powerpc arch

[Philippe Gerum <rpm@xenomai.org>]

On Fri, 2010-04-30 at 20:03 +0800, Peter Pan wrote:
> OK, I got that.
> 
> But which task mode should this latency test be run for?
> user-mode task or kernel periodic task?
> 

It depends on your particular use case, since the latency value is
global for all modes, but I guess you will likely run userland rt apps,
which is recommended, so latency [-t0] is what you look for. Userland
latency should be higher than any other modes.

> 2010/4/30 Philippe Gerum <rpm@xenomai.org>:
> > On Fri, 2010-04-30 at 17:17 +0800, Peter Pan wrote:
> >> I set the /proc/xenomai/latency to 0, and get some latency results.
> >> How could I set the latency to a proper value? I'm on vocation now. I
> >> will post my latency result when I'm back to work.
> >
> > You should run the /usr/xenomai/bin/latency test when your calibrated
> > latency is reset to 0, for a few seconds on your idle platform. In the
> > left most column after you stopped the test, you should see the minimum
> > latency value, which your reported to be negative. Use abs(min-lat) as
> > the next /proc/xenomai/latency value, and redo the test, until you end
> > up with a min-lat slightly higher than 0, from a few tenths of
> > nanoseconds.
> >
> >>
> >> 2010/4/30 Philippe Gerum <rpm@xenomai.org>:
> >> > On Fri, 2010-04-30 at 08:16 +0800, Peter Pan wrote:
> >> >> It's an EVM board of PPC460GT.
> >> >>
> >> >> I think the processor is very powerful, that may make xenomai workable
> >> >> on our system.
> >> >
> >> >> I'll try to reduce the latency to a proper value.
> >> >
> >> > When you are done, I'd be interested in knowing the proper calibration
> >> > value for this platform, so that I can pre-set it in
> >> > include/asm-powerpc/calibration.h for future users.
> >> >
> >> > PS: echo 0 > /proc/xenomai/latency is the way to disable the
> >> > anticipation in setting timer shots, so that you can determine the
> >> > minimum latency of your platform, i.e. abs(min-lat) from the latency
> >> > test output, on an idle system.
> >> >
> >> > TIA,
> >> >
> >
> >
> > --
> > Philippe.
> >
> >
> >


-- 
Philippe.