Re: [Xenomai-help] CPU load over 90%[Scanned]

["Nathan Lauener" <nathan.lauener@domain.hid>]

Jan Kiszka wrote:

>Lauener Nathan wrote:
>  
>
>>Hi, 
>>I am using Xenomai to read data from different sensors in real time from
>>user space. So far I am reading position data from a device attached to
>>a serial port. The CPU load is at about 1%. I also have a
>>microcontroller attached via USB to read encoder data. The USB device is
>>a USB-to-serial converter. As soon as I open the (USB-)serial port with
>>normal systemcalls and read the incoming data my CPU load skyrockets to
>>over 90%. I only read about 30 bytes every 100ms.
>>I ran the application on a much newer computer also to rule out any
>>buggy hardware. The results stayed the same. Intensively searching the
>>mailing list and provided documentation have not helped solve the
>>problem. 
>>I'm using Xenomai 2.1.0 with kernel 2.6.15.6. Xenomai is compiled into
>>the kernel. I also use the driver xeno_16550A loaded as module. The
>>USB-to-serial bridge used is a CP2101 from Silabs. 
>>    
>>
>
>Is there any IRQ conflict between the USB host controller and some
>RT-device? Please check /proc/interrupts and /proc/xenomai/irq.
>  
>
There is no conflict (interrupt 0 (timer) is the only interrupt 
mentioned in both listings).

>Which process is consuming your CPU time? At system or at user level?
>  
>
It seems that the system consumes the CPU time. Here are the first few 
lines from opreport

CPU: CPU with timer interrupt, speed 0 MHz (estimated)
Profiling through timer interrupt
samples  %        image name               app name                 
symbol name
1733     31.9742  vmlinux                  vmlinux                  
default_idle
1151     21.2362  vmlinux                  vmlinux                  
__ipipe_trace
601      11.0886  libqt-mt.so.3.3.3        libqt-mt.so.3.3.3        (no 
symbols)
528       9.7417  libc-2.3.2.so            libc-2.3.2.so            (no 
symbols)
305       5.6273  vmlinux                  vmlinux                  
__ipipe_unstall_root
184       3.3948  vmlinux                  vmlinux                  
__ipipe_dispatch_event
122       2.2509  anon (tgid:4322 range:0x81fb000-0x89b2000) 
Xorg                     (no symbols)
100       1.8450  libstdc++.so.5.0.7       libstdc++.so.5.0.7       (no 
symbols)
97        1.7897  vmlinux                  vmlinux                  mcount

It looks like the systems gets stuck on the idle task. I do not know 
what __ipipe_trace exactly does.

>Jan
>
>  
>
In my current design I acquire and process the data in the same programm 
using the Xenomai native skin from user space. This means I link the 
Xenomai-native and rtdm libraries with several graphics and mathematical 
libraries. Could this lead to conflicts or problems with Xenomai? 

Nathan