Hi!
Vincent reported that on some machines affinity stopped working,
apparently sometimes sysconf (_SC_NPROCESSORS_CONF) is smaller than
the minimum number of logical CPUs kernel allows for sched_getaffinity
syscall :(, and I don't seem to see how to query that magic number.
So, this patch, if pthread_getaffinity_np fails with EINVAL, retries
with a bigger mask set (if the starting cpusetsize was smaller than
sizeof (cpu_set_t), then it goes on with that size (1024 CPUs), then
always doubles the size), and after successful pthread_getaffinity_np
looks through the affinity mask if it could use smaller value for the
places array and pthread_setaffinity_np syscalls. gomp_get_cpuset_size
is the larger of the sizes then, for use in pthread_getaffinity_np
and the size of gomp_cpusetp bitmask, gomp_cpuset_size is equal to that
or smaller and is what is passed to pthread_setaffinity_np. Say, kernel
configured with 32 present CPUs and up to 96 hotplug CPUs, could have
gomp_get_cpuset_size 128 (1024 CPUs) or perhaps 16 (128 CPUs), while
gomp_cpuset_size 8 (up to 64 CPUs).
2013-10-07 Jakub Jelinek <ja...@redhat.com>
PR libgomp/58642
* config/linux/proc.c: Include errno.h.
(gomp_get_cpuset_size): New variable.
(gomp_cpuset_popcount): Add cpusetsize argument, use it instead of
gomp_cpuset_size.
(gomp_init_num_threads): If CPU_ALLOC_SIZE is defined and
pthread_getaffinity_np returned EINVAL, increase gomp_cpuset_size
and retry. After successful pthread_getaffinity_np copy
gomp_cpuset_size to gomp_get_cpuset_size and try to find out
minimum gomp_cpuset_size that covers all the CPUs set in gomp_cpusetp.
(get_num_procs): Pass gomp_get_cpuset_size rather than gomp_cpuset_size
to pthread_getaffinity_np, adjust gomp_cpuset_popcount caller.
* config/linux/proc.h (gomp_cpuset_popcount): Add cpusetsize argument.
* config/linux/affinity.c (gomp_affinity_finalize_place_list,
gomp_affinity_init_level): Adjust gomp_cpuset_popcount callers.
* testsuite/libgomp.c/affinity-1.c (pthread_getaffinity_np): Set
contig_cpucount from the first successful pthread_getaffinity_np
call, rather than just first call.
--- libgomp/config/linux/proc.c.jj 2013-10-04 09:03:01.000000000 +0200
+++ libgomp/config/linux/proc.c 2013-10-07 09:31:00.350979942 +0200
@@ -30,6 +30,7 @@
#endif
#include "libgomp.h"
#include "proc.h"
+#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#ifdef HAVE_GETLOADAVG
@@ -40,17 +41,18 @@
#ifdef HAVE_PTHREAD_AFFINITY_NP
unsigned long gomp_cpuset_size;
+static unsigned long gomp_get_cpuset_size;
cpu_set_t *gomp_cpusetp;
unsigned long
-gomp_cpuset_popcount (cpu_set_t *cpusetp)
+gomp_cpuset_popcount (unsigned long cpusetsize, cpu_set_t *cpusetp)
{
#ifdef CPU_COUNT_S
/* glibc 2.7 and above provide a macro for this. */
- return CPU_COUNT_S (gomp_cpuset_size, cpusetp);
+ return CPU_COUNT_S (cpusetsize, cpusetp);
#else
#ifdef CPU_COUNT
- if (gomp_cpuset_size == sizeof (cpu_set_t))
+ if (cpusetsize == sizeof (cpu_set_t))
/* glibc 2.6 and above provide a macro for this. */
return CPU_COUNT (cpusetp);
#endif
@@ -59,7 +61,7 @@ gomp_cpuset_popcount (cpu_set_t *cpusetp
extern int check[sizeof (cpusetp->__bits[0]) == sizeof (unsigned long int)
? 1 : -1];
- for (i = 0; i < gomp_cpuset_size / sizeof (cpusetp->__bits[0]); i++)
+ for (i = 0; i < cpusetsize / sizeof (cpusetp->__bits[0]); i++)
{
unsigned long int mask = cpusetp->__bits[i];
if (mask == 0)
@@ -86,24 +88,55 @@ gomp_init_num_threads (void)
#endif
gomp_cpusetp = (cpu_set_t *) gomp_malloc (gomp_cpuset_size);
- if (pthread_getaffinity_np (pthread_self (), gomp_cpuset_size,
- gomp_cpusetp) == 0)
+ do
{
- /* Count only the CPUs this process can use. */
- gomp_global_icv.nthreads_var = gomp_cpuset_popcount (gomp_cpusetp);
- if (gomp_global_icv.nthreads_var == 0)
+ int ret = pthread_getaffinity_np (pthread_self (), gomp_cpuset_size,
+ gomp_cpusetp);
+ if (ret == 0)
{
- gomp_global_icv.nthreads_var = 1;
- free (gomp_cpusetp);
- gomp_cpusetp = NULL;
+ unsigned long i;
+ /* Count only the CPUs this process can use. */
+ gomp_global_icv.nthreads_var
+ = gomp_cpuset_popcount (gomp_cpuset_size, gomp_cpusetp);
+ if (gomp_global_icv.nthreads_var == 0)
+ break;
+ gomp_get_cpuset_size = gomp_cpuset_size;
+#ifdef CPU_ALLOC_SIZE
+ for (i = gomp_cpuset_size * 8; i; i--)
+ if (CPU_ISSET_S (i - 1, gomp_cpuset_size, gomp_cpusetp))
+ break;
+ gomp_cpuset_size = CPU_ALLOC_SIZE (i);
+#endif
+ return;
}
- return;
- }
- else
- {
- free (gomp_cpusetp);
- gomp_cpusetp = NULL;
+ if (ret != EINVAL)
+ break;
+#ifdef CPU_ALLOC_SIZE
+ if (gomp_cpuset_size < sizeof (cpu_set_t))
+ gomp_cpuset_size = sizeof (cpu_set_t);
+ else
+ gomp_cpuset_size = gomp_cpuset_size * 2;
+ if (gomp_cpuset_size < 8 * sizeof (cpu_set_t))
+ gomp_cpusetp
+ = (cpu_set_t *) gomp_realloc (gomp_cpusetp, gomp_cpuset_size);
+ else
+ {
+ /* Avoid gomp_fatal if too large memory allocation would be
+ requested, e.g. kernel returning EINVAL all the time. */
+ void *p = realloc (gomp_cpusetp, gomp_cpuset_size);
+ if (p == NULL)
+ break;
+ gomp_cpusetp = (cpu_set_t *) p;
+ }
+#else
+ break;
+#endif
}
+ while (1);
+ gomp_cpuset_size = 0;
+ gomp_global_icv.nthreads_var = 1;
+ free (gomp_cpusetp);
+ gomp_cpusetp = NULL;
#endif
#ifdef _SC_NPROCESSORS_ONLN
gomp_global_icv.nthreads_var = sysconf (_SC_NPROCESSORS_ONLN);
@@ -118,10 +151,10 @@ get_num_procs (void)
{
/* Count only the CPUs this process can use. */
if (gomp_cpusetp
- && pthread_getaffinity_np (pthread_self (), gomp_cpuset_size,
+ && pthread_getaffinity_np (pthread_self (), gomp_get_cpuset_size,
gomp_cpusetp) == 0)
{
- int ret = gomp_cpuset_popcount (gomp_cpusetp);
+ int ret = gomp_cpuset_popcount (gomp_get_cpuset_size, gomp_cpusetp);
return ret != 0 ? ret : 1;
}
}
--- libgomp/config/linux/proc.h.jj 2013-10-01 13:48:00.000000000 +0200
+++ libgomp/config/linux/proc.h 2013-10-07 09:09:08.576141237 +0200
@@ -30,7 +30,8 @@
#ifdef HAVE_PTHREAD_AFFINITY_NP
extern unsigned long gomp_cpuset_size attribute_hidden;
extern cpu_set_t *gomp_cpusetp attribute_hidden;
-extern unsigned long gomp_cpuset_popcount (cpu_set_t *) attribute_hidden;
+extern unsigned long gomp_cpuset_popcount (unsigned long, cpu_set_t *)
+ attribute_hidden;
#endif
#endif /* GOMP_PROC_H */
--- libgomp/config/linux/affinity.c.jj 2013-10-04 09:27:56.000000000 +0200
+++ libgomp/config/linux/affinity.c 2013-10-07 09:30:52.523021443 +0200
@@ -193,7 +193,7 @@ gomp_affinity_finalize_place_list (bool
bool nonempty = false;
#ifdef CPU_AND_S
CPU_AND_S (gomp_cpuset_size, cpusetp, cpusetp, gomp_cpusetp);
- nonempty = gomp_cpuset_popcount (cpusetp) != 0;
+ nonempty = gomp_cpuset_popcount (gomp_cpuset_size, cpusetp) != 0;
#else
unsigned long k, max = gomp_cpuset_size / sizeof (cpusetp->__bits[0]);
for (k = 0; k < max; k++)
@@ -228,7 +228,8 @@ gomp_affinity_init_level (int level, uns
if (gomp_cpusetp)
{
- unsigned long maxcount = gomp_cpuset_popcount (gomp_cpusetp);
+ unsigned long maxcount
+ = gomp_cpuset_popcount (gomp_cpuset_size, gomp_cpusetp);
if (count > maxcount)
count = maxcount;
}
--- libgomp/testsuite/libgomp.c/affinity-1.c.jj 2013-10-04 15:58:13.000000000
+0200
+++ libgomp/testsuite/libgomp.c/affinity-1.c 2013-10-07 09:31:53.884695701
+0200
@@ -76,23 +76,26 @@ int
pthread_getaffinity_np (pthread_t thread, size_t cpusetsize, cpu_set_t *cpuset)
{
int ret;
+ unsigned long i, max;
if (orig_getaffinity_np == NULL)
{
- unsigned long i, max;
orig_getaffinity_np = (int (*) (pthread_t, size_t, cpu_set_t *))
dlsym (RTLD_NEXT, "pthread_getaffinity_np");
if (orig_getaffinity_np == NULL)
exit (0);
- ret = orig_getaffinity_np (thread, cpusetsize, cpuset);
- if (ret != 0)
- return ret;
+ }
+ ret = orig_getaffinity_np (thread, cpusetsize, cpuset);
+ if (ret != 0)
+ return ret;
+ if (contig_cpucount == 0)
+ {
max = 8 * cpusetsize;
for (i = 0; i < max; i++)
if (!CPU_ISSET_S (i, cpusetsize, cpuset))
break;
contig_cpucount = i;
}
- return orig_getaffinity_np (thread, cpusetsize, cpuset);
+ return ret;
}
#endif
Jakub
