From e4ba7a600e70bce0065a2fde0f2f85cdee746cfb Mon Sep 17 00:00:00 2001
From: Jakub Jelinek <jakub@redhat.com>
Date: Tue, 20 Apr 2010 17:37:51 +0200
Subject: [PATCH] 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
---
libgomp/ChangeLog | 7 +++++++
libgomp/config/linux/affinity.c | 17 ++++++++++++++---
libgomp/config/linux/proc.c | 24 ++++++------------------
3 files changed, 27 insertions(+), 21 deletions(-)
diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index 7756ac15a2e0..95c1f00cac9e 100644
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -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.
diff --git a/libgomp/config/linux/affinity.c b/libgomp/config/linux/affinity.c
index 40519e8896ae..da9f3d8fdcb0 100644
--- a/libgomp/config/linux/affinity.c
+++ b/libgomp/config/linux/affinity.c
@@ -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);
diff --git a/libgomp/config/linux/proc.c b/libgomp/config/linux/proc.c
index dad6237e6099..01f51dfa1938 100644
--- a/libgomp/config/linux/proc.c
+++ b/libgomp/config/linux/proc.c
@@ -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
--
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