[nSLUG] IXP4xx and Kernel Scheduler

Van Roekel, Jeff jeff.vanroekel at sencore.com
Tue Nov 25 13:31:53 AST 2008


I'm not able to change the priority of processes on my IXP425 based
system.  To be more specific I can change the priority just fine but
when I do, the higher or prioritized thread never gets rescheduled to
yield the process to lower priority threads.


I'm running kernel version so it's a little older than the most
current stuff but I'm having hard time believing that this basic
functionality isn't supported.  I checked the system timer interrupt and
it appears to be calling scheduler_tick().  I created a test program
that runs just fine on X86 architectures(single CPU) but on my ixp425
the critical thread never yields the CPU.  Any support or directions on
how to debug this problem would be really appreciated.



PriorityTest Results with sleep() functions in critical threads.  Notice
the regular or normal priority thread never seemed to produce output.  I
still cant CTL-C the process and have to reboot.



This is the same code as above just compiled and ran on the x86




Compile Command:

X86: gcc priorityTest.c -lpthread -o prioritytestx86

IXP425:  xscale_be-sencore-gcc priorityTest.c -lpthread -o prioritytest


FYI:  I've posted my question/dilemma on
linux-arm-kernel at lists.arm.linux.org.uk and have received a reply from
Karl that I'm looking into.  Any other help from people on this list
would be appreciated as well. 



Jeff Van Roekel


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