From: Ian Jackson <ian@davenant.relativity.greenend.org.uk>
Date: Sun, 28 Sep 2008 23:13:52 +0000 (+0100)
Subject: do not bother with barriers and stuff if nprocessors=1
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?a=commitdiff_plain;h=4c2fa1edde3eff50648b6782e0b6e63add9b4943;p=moebius2.git

do not bother with barriers and stuff if nprocessors=1
---

diff --git a/parallel.c b/parallel.c
index d9782df..f5841ee 100644
--- a/parallel.c
+++ b/parallel.c
@@ -54,7 +54,7 @@ void inparallel(const struct Vertices *vertices,
 
   int s, r;
 
-  if (!threads_started) {
+  if (NSECTIONS>1 && !threads_started) {
     r= pthread_barrier_init(&threads_barrier, 0, NSECTIONS);
     if (r) { errno=r; diee("pthread_barrier_init"); }
 
@@ -82,8 +82,10 @@ void inparallel(const struct Vertices *vertices,
 }
 
 void inparallel_barrier(void) {
-  int r;
-  r= pthread_barrier_wait(&threads_barrier);
-  if (r && r!=PTHREAD_BARRIER_SERIAL_THREAD)
-    { errno=r; diee("pthread_barrier_wait"); }
+  if (NSECTIONS>1) {
+    int r;
+    r= pthread_barrier_wait(&threads_barrier);
+    if (r && r!=PTHREAD_BARRIER_SERIAL_THREAD)
+      { errno=r; diee("pthread_barrier_wait"); }
+  }
 }