diff options
Diffstat (limited to 'linuxthreads/pthread.c')
| -rw-r--r-- | linuxthreads/pthread.c | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/linuxthreads/pthread.c b/linuxthreads/pthread.c index c264da5..551086f 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) |