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sna: Parse cpuinfo to determine the actual number of physical cores/caches 

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Chris Wilson 2013-01-24 20:58:53 +00:00
parent f597b64718
commit 326dcd75f2
1 changed files with 51 additions and 1 deletions
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52
src/sna/sna_threads.c
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@ -63,6 +63,54 @@ static void *__run__(void *arg)
return NULL;
}
#if defined(__GNUC__)
#define popcount(x) __builtin_popcount(x)
#else
static int popcount(unsigned int x)
{
int count = 0;
while (x) {
count += x&1;
x >>= 1;
}
return count;
}
#endif
static int
num_cores(void)
{
FILE *file = fopen("/proc/cpuinfo", "r");
int count = 0;
if (file) {
size_t len = 0;
char *line = NULL;
uint32_t processors = 0, cores = 0;
while (getline(&line, &len, file) != -1) {
int id;
if (sscanf(line, "physical id : %d", &id) == 1) {
if (id >= 32)
return 0;
processors |= 1 << id;
} else if (sscanf(line, "core id : %d", &id) == 1) {
if (id >= 32)
return 0;
cores |= 1 << id;
}
}
free(line);
fclose(file);
DBG(("%s: processors=0x%08x, cores=0x%08x\n",
__FUNCTION__, processors, cores));
count = popcount(processors) * popcount(cores);
}
return count;
}
void sna_threads_init(void)
{
int n;
@ -70,7 +118,9 @@ void sna_threads_init(void)
if (max_threads != -1)
return;
max_threads = sysconf (_SC_NPROCESSORS_ONLN) / 2;
max_threads = num_cores();
if (max_threads == 0)
max_threads = sysconf(_SC_NPROCESSORS_ONLN) / 2;
if (max_threads <= 1)
goto bail;