Question about setting affinity in 2.4

From: Phy Prabab
Date: Sun Feb 18 2007 - 21:02:37 EST

Hello everyone,

I am trying to set affinity on a program to make sure I can get the
best use of the cache as possible and to eliminate as much noise as
possible with running my program. I have tried unsuccessfully to set
affinity using sched_set/getaffinity and the CPU_SET macros. In
particular, I can not seem to get the process to use affinity I
specify as in:

int main () {
cpu_set_t mask;
cpu_set_t setmask;
long long x;
double foo;
printf("Mask set to %08lx\n", sched_getaffinity(0, &mask));
CPU_SET(1, &mask);
if (sched_setaffinity(0, &mask) == -1) {
printf("error setting affinity.");

printf("Mask is reset to %08lx\n", sched_getaffinity(0, &mask));
// do some long lasting calculations ....


No mater what I do, the process is never bond to the processor in
question as exposed by this little appy and by cat /proc/<pid>/cpu.
Is this just impossible to do?

Ah, the kernel I am using is RH 2.4.21-37.ELsmp.

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