diff options
| -rw-r--r-- | sysdeps/unix/sysv/linux/getsysstats.c | 94 |
1 files changed, 63 insertions, 31 deletions
diff --git a/sysdeps/unix/sysv/linux/getsysstats.c b/sysdeps/unix/sysv/linux/getsysstats.c index c98c8ce..d1ea074 100644 --- a/sysdeps/unix/sysv/linux/getsysstats.c +++ b/sysdeps/unix/sysv/linux/getsysstats.c @@ -50,9 +50,8 @@ __get_nprocs_sched (void) is an arbitrary values assuming such systems should be rare and there is no offline cpus. */ return max_num_cpus; - /* Some other error. 2 is conservative (not a uniprocessor system, so - atomics are needed). */ - return 2; + /* Some other error. */ + return 0; } static char * @@ -108,22 +107,19 @@ next_line (int fd, char *const buffer, char **cp, char **re, } static int -get_nproc_stat (char *buffer, size_t buffer_size) +get_nproc_stat (void) { + enum { buffer_size = 1024 }; + char buffer[buffer_size]; char *buffer_end = buffer + buffer_size; char *cp = buffer_end; char *re = buffer_end; - - /* Default to an SMP system in case we cannot obtain an accurate - number. */ - int result = 2; + int result = 0; const int flags = O_RDONLY | O_CLOEXEC; int fd = __open_nocancel ("/proc/stat", flags); if (fd != -1) { - result = 0; - char *l; while ((l = next_line (fd, buffer, &cp, &re, buffer_end)) != NULL) /* The current format of /proc/stat has all the cpu* entries @@ -139,8 +135,8 @@ get_nproc_stat (char *buffer, size_t buffer_size) return result; } -int -__get_nprocs (void) +static int +get_nprocs_cpu_online (void) { enum { buffer_size = 1024 }; char buffer[buffer_size]; @@ -179,7 +175,8 @@ __get_nprocs (void) } } - result += m - n + 1; + if (m >= n) + result += m - n + 1; l = endp; if (l < re && *l == ',') @@ -188,28 +185,18 @@ __get_nprocs (void) while (l < re && *l != '\n'); __close_nocancel_nostatus (fd); - - if (result > 0) - return result; } - return get_nproc_stat (buffer, buffer_size); + return result; } -libc_hidden_def (__get_nprocs) -weak_alias (__get_nprocs, get_nprocs) - -/* On some architectures it is possible to distinguish between configured - and active cpus. */ -int -__get_nprocs_conf (void) +static int +get_nprocs_cpu (void) { - /* Try to use the sysfs filesystem. It has actual information about - online processors. */ + int count = 0; DIR *dir = __opendir ("/sys/devices/system/cpu"); if (dir != NULL) { - int count = 0; struct dirent64 *d; while ((d = __readdir64 (dir)) != NULL) @@ -224,12 +211,57 @@ __get_nprocs_conf (void) __closedir (dir); - return count; } + return count; +} - enum { buffer_size = 1024 }; - char buffer[buffer_size]; - return get_nproc_stat (buffer, buffer_size); +static int +get_nprocs_fallback (void) +{ + int result; + + /* Try /proc/stat first. */ + result = get_nproc_stat (); + if (result != 0) + return result; + + /* Try sched_getaffinity. */ + result = __get_nprocs_sched (); + if (result != 0) + return result; + + /* We failed to obtain an accurate number. Be conservative: return + the smallest number meaning that this is not a uniprocessor system, + so atomics are needed. */ + return 2; +} + +int +__get_nprocs (void) +{ + /* Try /sys/devices/system/cpu/online first. */ + int result = get_nprocs_cpu_online (); + if (result != 0) + return result; + + /* Fall back to /proc/stat and sched_getaffinity. */ + return get_nprocs_fallback (); +} +libc_hidden_def (__get_nprocs) +weak_alias (__get_nprocs, get_nprocs) + +/* On some architectures it is possible to distinguish between configured + and active cpus. */ +int +__get_nprocs_conf (void) +{ + /* Try /sys/devices/system/cpu/ first. */ + int result = get_nprocs_cpu (); + if (result != 0) + return result; + + /* Fall back to /proc/stat and sched_getaffinity. */ + return get_nprocs_fallback (); } libc_hidden_def (__get_nprocs_conf) weak_alias (__get_nprocs_conf, get_nprocs_conf) |