Hi Philippe,
Thank you for the suggestion. I will give it a try and let you know.
Regards
Bharath
On Wed, Aug 25, 2010 at 4:22 PM, Philippe Gerum <r...@xenomai.org> wrote:
> On Wed, 2010-08-25 at 12:06 +0200, Bharath Achuta Bhat wrote:
> > Hi Philippe,
> > It is an mmap-ed I/O memory.
>
> This is a TLB miss which ends up in a heavyweight call to fill the linux
> page table entry. Try to pre-fault the I/O memory region if possible,
> reading some bytes within the same 4k page.
>
> >
> >
> > Regards
> > Bharath
> >
> > On Wed, Aug 25, 2010 at 11:53 AM, Philippe Gerum <r...@xenomai.org>
> > wrote:
> > On Wed, 2010-08-25 at 11:12 +0200, Bharath Achuta Bhat wrote:
> > > Hello Xenomai experts,
> > >
> > >
> > > I am running a xenomai-2.5.1 patched kernel (v 2.6.30.3)
> > with ipipe
> > > version 2.7-06.
> > > The target is powerpc (MPC8533E).
> > > My application is switching to the secondary mode (I guess
> > because of
> > > a page-fault) when ntohl() is called.
> > > This is a libc function and I am wondering why only this
> > function
> > > (ntohl()) is causing a page-fault.
> >
> >
> > What memory are you reading from / writing to in the statement
> > involving
> > ntohl()? Is this plain RAM, or mapped I/O memory?
> >
> > >
> > >
> > > Here is how the application looks like
> > >
> > >
> > > main ()
> > > {
> > > ...
> > > ...
> > > /* Avoids memory swapping for this program */
> > > mlockall(MCL_CURRENT | MCL_FUTURE);
> > >
> > >
> > > ......
> > > ......
> > > /* signal handlers */
> > > .....
> > > .....
> > > /* create communication pipes */
> > > rt_pipe_create(&tPipe1, .....
> > > rt_pipe_create(&tPipe2,.......
> > >
> > >
> > > /* create RT tasks */
> > > rt_task_create(&tTask1,.....
> > > rt_task_create(&tTask2,......
> > > ...........
> > > ..........
> > >
> > >
> > > /* start the RT tasks */
> > > rt_task_start(&tTask1,.....
> > > ..............
> > > ..............
> > >
> > >
> > > /* turn the current thread into RT function */
> > > ret = rt_task_shadow(NULL, "RT main function", 1, T_SUSP);
> > >
> > >
> > > ....
> > > ....
> > >
> > >
> > > }
> > >
> > >
> > > One of the rt tasks created calls ntohl() and switches to
> > secondary
> > > mode.
> > > Is there a way to avoid it ?
> > >
> > >
> > > --
> > > Thanks and regards
> > > Bharath
> > >
> >
> > > _______________________________________________
> > > Xenomai-help mailing list
> > > Xenomai-help@gna.org
> > > https://mail.gna.org/listinfo/xenomai-help
> >
> > --
> > Philippe.
> >
> >
> >
> >
> >
> > --
> > Thanks and regards
> > Bharath
> >
>
> --
> Philippe.
>
>
>
--
Thanks and regards
Bharath
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