void myth_get_available_cpus(void) {
int i;
int n_specified_cpus
= myth_parse_cpu_list("MYTH_CPU_LIST", myth_cpu_list, N_MAX_CPUS);
n_available_cpus = 0;
if (n_specified_cpus == -1) {
fprintf(stderr, "myth: malformed MYTH_CPU_LIST ignored\n");
n_specified_cpus = 0; /* as if it wasn't specified */
}
if (n_specified_cpus == 0) {
/* MYTH_CPU_LIST not specified. treat as if it was 0,1,2,3,4,5,... */
n_specified_cpus = myth_get_n_available_cpus();
if (n_specified_cpus == -1) {
fprintf(stderr, "myth: the platform does not tell the number of CPUs. to bind workers to cores, consider using MYTH_CPU_LIST environment variable\n");
/* we still go ahead, but does not do anything except for
issuing a warning and return */
}
for (i = 0; i < n_specified_cpus; i++) {
myth_cpu_list[i] = i;
}
}
/* got user-specified list of cpus.
now, intersect with actually available cpus */
#if defined(HAVE_SCHED_GETAFFINITY)
{
cpu_set_t cset;
/* get cpu set we can use */
sched_getaffinity(getpid(), sizeof(cpu_set_t), &cset);
for (i = 0; i < n_specified_cpus; i++){
/* is myth_cpu_list[i] available? */
if (CPU_ISSET(myth_cpu_list[i], &cset)) {
/* yes, use it */
worker_cpu[n_available_cpus] = myth_cpu_list[i];
n_available_cpus++;
}
}
}
#else /* no HAVE_SCHED_GETAFFINITY */
for (i = 0; i < n_specified_cpus; i++){
worker_cpu[n_available_cpus] = myth_cpu_list[i];
n_available_cpus++;
}
#endif /* HAVE_SCHED_GETAFFINITY */
if (n_available_cpus == 0) {
fprintf(stderr, "myth: could not get any available CPUs. won't bind worker to cores\n");
}
#if 0 /* debug */
printf("%d available CPUs:", n_available_cpus);
for (i = 0; i < n_available_cpus; i++) {
printf(" ");
printf("%d", worker_cpu[i]);
}
printf("\n");
#endif /* debug */
}
void myth_init_process_affinity_info(void)
{
int n = myth_parse_cpu_list("MYTH_CPU_LIST", myth_cpu_list, CPU_SETSIZE);
if (n == -1) {
fprintf(stderr, "MYTH_CPU_LIST ignored\n");
}
cpu_set_t cset;
sched_getaffinity(getpid(),sizeof(cpu_set_t),&cset);
int i;
for (i=0;i<CPU_SETSIZE;i++){
CPU_ZERO(&worker_cpusets[i]);
}
available_cores=0;
int sz = (n ? n : CPU_SETSIZE);
for (i=0;i<sz;i++){
if (CPU_ISSET((n>0)?myth_cpu_list[i]:i,&cset)){
CPU_SET((n>0)?myth_cpu_list[i]:i,&worker_cpusets[available_cores]);
available_cores++;
}
}
#if 0
printf("%d available cores:", available_cores);
for (i = 0; i < available_cores; i++) {
int x;
int nx = 0;
printf(" ");
printf("{");
for (x = 0; x < CPU_SETSIZE; x++) {
if (CPU_ISSET(x, &worker_cpusets[i])) {
if (nx > 0) printf(",");
printf("%d", x);
}
}
printf("}");
}
printf("\n");
#endif
}