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re PR libgomp/43706 (scheduling two threads on one core leads to starvation) 

PR libgomp/43706
	* config/linux/affinity.c (gomp_init_affinity): Decrease
	gomp_available_cpus if affinity mask confines the process to fewer
	CPUs.
	* config/linux/proc.c (get_num_procs): If gomp_cpu_affinity is
	non-NULL, just return gomp_available_cpus.

From-SVN: r158565
This commit is contained in:
Jakub Jelinek 2010-04-20 17:37:51 +02:00 committed by Jakub Jelinek
parent 5221d7a91b
commit e4ba7a600e
3 changed files with 27 additions and 21 deletions
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7
libgomp/ChangeLog
View File

@ -1,5 +1,12 @@
2010-04-20 Jakub Jelinek <jakub@redhat.com> 2010-04-20 Jakub Jelinek <jakub@redhat.com>
PR libgomp/43706
* config/linux/affinity.c (gomp_init_affinity): Decrease
gomp_available_cpus if affinity mask confines the process to fewer
CPUs.
* config/linux/proc.c (get_num_procs): If gomp_cpu_affinity is
non-NULL, just return gomp_available_cpus.
PR libgomp/43569 PR libgomp/43569
* sections.c (gomp_sections_init): Initialize ws->mode. * sections.c (gomp_sections_init): Initialize ws->mode.

17
libgomp/config/linux/affinity.c
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@ -1,4 +1,4 @@
/* Copyright (C) 2006, 2007, 2008, 2009 Free Software Foundation, Inc. /* Copyright (C) 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
Contributed by Jakub Jelinek <jakub@redhat.com>. Contributed by Jakub Jelinek <jakub@redhat.com>.
This file is part of the GNU OpenMP Library (libgomp). This file is part of the GNU OpenMP Library (libgomp).
@ -39,8 +39,9 @@ static unsigned int affinity_counter;
void void
gomp_init_affinity (void) gomp_init_affinity (void)
{ {
cpu_set_t cpuset; cpu_set_t cpuset, cpusetnew;
size_t idx, widx; size_t idx, widx;
unsigned long cpus = 0;
if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset), &cpuset)) if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset), &cpuset))
{ {
@ -51,10 +52,18 @@ gomp_init_affinity (void)
return; return;
} }
CPU_ZERO (&cpusetnew);
for (widx = idx = 0; idx < gomp_cpu_affinity_len; idx++) for (widx = idx = 0; idx < gomp_cpu_affinity_len; idx++)
if (gomp_cpu_affinity[idx] < CPU_SETSIZE if (gomp_cpu_affinity[idx] < CPU_SETSIZE
&& CPU_ISSET (gomp_cpu_affinity[idx], &cpuset)) && CPU_ISSET (gomp_cpu_affinity[idx], &cpuset))
gomp_cpu_affinity[widx++] = gomp_cpu_affinity[idx]; {
if (! CPU_ISSET (gomp_cpu_affinity[idx], &cpusetnew))
{
cpus++;
CPU_SET (gomp_cpu_affinity[idx], &cpusetnew);
}
gomp_cpu_affinity[widx++] = gomp_cpu_affinity[idx];
}
if (widx == 0) if (widx == 0)
{ {
@ -66,6 +75,8 @@ gomp_init_affinity (void)
} }
gomp_cpu_affinity_len = widx; gomp_cpu_affinity_len = widx;
if (cpus < gomp_available_cpus)
gomp_available_cpus = cpus;
CPU_ZERO (&cpuset); CPU_ZERO (&cpuset);
CPU_SET (gomp_cpu_affinity[0], &cpuset); CPU_SET (gomp_cpu_affinity[0], &cpuset);
pthread_setaffinity_np (pthread_self (), sizeof (cpuset), &cpuset); pthread_setaffinity_np (pthread_self (), sizeof (cpuset), &cpuset);

24
libgomp/config/linux/proc.c
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@ -1,4 +1,5 @@
/* Copyright (C) 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. /* Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010
Free Software Foundation, Inc.
Contributed by Jakub Jelinek <jakub@redhat.com>. Contributed by Jakub Jelinek <jakub@redhat.com>.
This file is part of the GNU OpenMP Library (libgomp). This file is part of the GNU OpenMP Library (libgomp).
@ -104,26 +105,13 @@ get_num_procs (void)
} }
else else
{ {
size_t idx;
static int affinity_cpus;
/* We can't use pthread_getaffinity_np in this case /* We can't use pthread_getaffinity_np in this case
(we have changed it ourselves, it binds to just one CPU). (we have changed it ourselves, it binds to just one CPU).
Count instead the number of different CPUs we are Count instead the number of different CPUs we are
using. */ using. gomp_init_affinity updated gomp_available_cpus to
CPU_ZERO (&cpuset); the number of CPUs in the GOMP_AFFINITY mask that we are
if (affinity_cpus == 0) allowed to use though. */
{ return gomp_available_cpus;
int cpus = 0;
for (idx = 0; idx < gomp_cpu_affinity_len; idx++)
if (! CPU_ISSET (gomp_cpu_affinity[idx], &cpuset))
{
cpus++;
CPU_SET (gomp_cpu_affinity[idx], &cpuset);
}
affinity_cpus = cpus;
}
return affinity_cpus;
} }
#endif #endif
#ifdef _SC_NPROCESSORS_ONLN #ifdef _SC_NPROCESSORS_ONLN