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

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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>
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
* sections.c (gomp_sections_init): Initialize ws->mode.

17
libgomp/config/linux/affinity.c
View file

@ -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>.
This file is part of the GNU OpenMP Library (libgomp).
@ -39,8 +39,9 @@ static unsigned int affinity_counter;
void
gomp_init_affinity (void)
{
cpu_set_t cpuset;
cpu_set_t cpuset, cpusetnew;
size_t idx, widx;
unsigned long cpus = 0;
if (pthread_getaffinity_np (pthread_self (), sizeof (cpuset), &cpuset))
{
@ -51,10 +52,18 @@ gomp_init_affinity (void)
return;
}
CPU_ZERO (&cpusetnew);
for (widx = idx = 0; idx < gomp_cpu_affinity_len; idx++)
if (gomp_cpu_affinity[idx] < CPU_SETSIZE
&& 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)
{
@ -66,6 +75,8 @@ gomp_init_affinity (void)
}
gomp_cpu_affinity_len = widx;
if (cpus < gomp_available_cpus)
gomp_available_cpus = cpus;
CPU_ZERO (&cpuset);
CPU_SET (gomp_cpu_affinity[0], &cpuset);
pthread_setaffinity_np (pthread_self (), sizeof (cpuset), &cpuset);

24
libgomp/config/linux/proc.c
View file

@ -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>.
This file is part of the GNU OpenMP Library (libgomp).
@ -104,26 +105,13 @@ get_num_procs (void)
}
else
{
size_t idx;
static int affinity_cpus;
/* We can't use pthread_getaffinity_np in this case
(we have changed it ourselves, it binds to just one CPU).
Count instead the number of different CPUs we are
using. */
CPU_ZERO (&cpuset);
if (affinity_cpus == 0)
{
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;
using. gomp_init_affinity updated gomp_available_cpus to
the number of CPUs in the GOMP_AFFINITY mask that we are
allowed to use though. */
return gomp_available_cpus;
}
#endif
#ifdef _SC_NPROCESSORS_ONLN