On 05/22/12 21:44, Philippe Gerum wrote:
On 05/22/2012 06:09 PM, Arnout Vandecappelle wrote:
Hoi,
After a few minutes of running my application, I see this:
# cat /proc/xenomai/stat
CPU PID MSW CSW PF STAT %CPU NAME
1 828 22 65 0 00300182 9.8 bench_RTnet_scope_thread_loop
1 839 2 46627538 0 00300186 53.8 bench_RTnet
...
i.e. the bench_RTnet_scope_thread_loop takes 10% CPU but no
context switches. How is this possible? I've looked at the
source code and can't find an explanation: when the exectime
accounting is updated, the csw is incremented as well (in
__xnpod_schedule()).
Unless your thread which seems to repeatedly attempt to pend on some sync
object has its wait condition satisfied on
entry to the syscall most of the time, which may cause __xnpod_schedule() to
leave it running without incrementing the
switch count.
It is indeed possible that my application does something like that. But
wouldn't the switch count be incremented every time the bench_RTnet thread
is executed? That thread runs at 20kHz and at higher priority so it should
pre-empt the other one, which should lead to context switches in the _loop
thread.
Unfortunately, I can't reproduce the situation anymore... If I can I'll
try with Xenomai 2.6.0.
Regards,
Arnout
--
Arnout Vandecappelle arnout at mind be
Senior Embedded Software Architect +32-16-286540
Essensium/Mind http://www.mind.be
G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven
LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle
GPG fingerprint: 7CB5 E4CC 6C2E EFD4 6E3D A754 F963 ECAB 2450 2F1F
_______________________________________________
Xenomai mailing list
[email protected]
http://www.xenomai.org/mailman/listinfo/xenomai
