about summary refs log tree commit diff
path: root/linuxthreads/pthread.c
diff options
context:
space:
mode:
Diffstat (limited to 'linuxthreads/pthread.c')
-rw-r--r--linuxthreads/pthread.c36
1 files changed, 35 insertions, 1 deletions
diff --git a/linuxthreads/pthread.c b/linuxthreads/pthread.c
index c264da53ab..551086f84b 100644
--- a/linuxthreads/pthread.c
+++ b/linuxthreads/pthread.c
@@ -23,6 +23,7 @@
 #include <fcntl.h>
 #include <sys/wait.h>
 #include <sys/resource.h>
+#include <sys/sysctl.h>
 #include <shlib-compat.h>
 #include "pthread.h"
 #include "internals.h"
@@ -311,6 +312,39 @@ __libc_allocate_rtsig (int high)
 #endif
 }
 
+/* The function we use to get the kernel revision.  */
+extern int __sysctl (int *name, int nlen, void *oldval, size_t *oldlenp,
+		     void *newval, size_t newlen);
+
+/* Test whether the machine has more than one processor.  This is not the
+   best test but good enough.  More complicated tests would require `malloc'
+   which is not available at that time.  */
+static int
+is_smp_system (void)
+{
+  static const int sysctl_args[] = { CTL_KERN, KERN_VERSION };
+  char buf[512];
+  size_t reslen = sizeof (buf);
+
+  /* Try reading the number using `sysctl' first.  */
+  if (__sysctl ((int *) sysctl_args,
+		sizeof (sysctl_args) / sizeof (sysctl_args[0]),
+		buf, &reslen, NULL, 0) < 0)
+    {
+      /*This was not successful.  Now try reading the /proc filesystem.  */
+      int fd = __open ("/proc/sys/kernel/version", O_RDONLY);
+      if (fd == -1
+	  || (reslen = __read (fd, buf, sizeof (buf))) <= 0)
+	/* This also didn't work.  We give up and say it's a UP machine.  */
+	buf[0] = '\0';
+
+      __close (fd);
+    }
+
+  return strstr (buf, "SMP") != NULL;
+}
+
+
 /* Initialize the pthread library.
    Initialization is split in two functions:
    - a constructor function that blocks the __pthread_sig_restart signal
@@ -410,7 +444,7 @@ static void pthread_initialize(void)
   else
     __on_exit (pthread_exit_process, NULL);
   /* How many processors.  */
-  __pthread_smp_kernel = sysconf (_SC_NPROCESSORS_ONLN) > 1;
+  __pthread_smp_kernel = is_smp_system ();
 }
 
 void __pthread_initialize(void)