Hi --
--- In "gebbet00" <> wrote:
>
> --- In "Michael" <michael@> wrote:
> >
> > > ...that you've used in a TS-7400? I've used the same in i386
and
> > > x86_64 systems and of course it works OK. Problem is on
TS-7400.
> > > tv_usec has the same value in start and tm.
> > >
> > > I wanted to ask before diving into it.
> >
> >
> > The Cirrus kernel that our kernel is based on has a "bug" where
the
> > microsecond time only has a resolution equal to the clock tick
(e.g. it
Well, it's a bug, but it's more of a kernel timer system design
fallout and not easy to fix. Not a cirrus or TS issue, but a kernel
issue. The good news though, is that it has been fixed for most
chips in recent 2.6 kernels. (Orion too, in just-released 2.6.25!)
> > increments 10,000us at a time). However if you are seeing
longer
> intervals
> > much longer then 10ms without no us advancement then I agree
with the
> > previous poster who suggested a bug in user code.
> >
> >
> > ______ Best Regards,
> > |__ __/ Michael Schmidt
> > || Software Engineer
> > ||echnologic Systems (EmbeddedARM.com)
> > || (480) 16610 East Laser Drive #10
> > |/ 837-5200 Fountain Hills, AZ 85268
> > http://oz.embeddedarm.com/~michael
> >
> Thanks for the response.
>
> No I haven't checked what the minimum interval is. In fact I have
a
> signal-based scan time of 50 ms and that worked OK, which added to
my
> puzzle.
>
> Now, what's the solution? What are the options?
>
One solution would be going to a recent 2.6 kernel, and enable "High
Resolution Timers" in the kernel config process. This will let the
library routines work with microsecond resolution, as advertised.
Google for it, or search the TS group archives for more info.
Another (highly frowned upon, IMHO) solution would be to recompile
the 2.4 kernel with HZ=1000 rather than HZ=100. But this only gives
a slight resolution increase (10x compared to 1000x or so with HRT),
at the expense of much greater CPU load.
Regards, ....... Charlie
------------------------------------
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|