Move get_logical_cpus() from lavc/pthread to lavu/cpu.

It will be useful in lavfi, and could conceivably be useful to the user
applications as well.

doc/APIchanges

@@ -13,6 +13,9 @@ libavutil:     2012-10-22
 
 API changes, most recent first:
 
+2013-xx-xx - xxxxxxx - lavu 52.12.0 - cpu.h
+  Add av_cpu_count() function for getting the number of logical CPUs.
+
 2013-05-xx - xxxxxxx - lavc 55.7.0 - avcodec.h
   Add picture_structure to AVCodecParserContext.
 

libavcodec/pthread.c

@@ -31,29 +31,12 @@
 
 #include "config.h"
 
-#if HAVE_SCHED_GETAFFINITY
-#define _GNU_SOURCE
-#include <sched.h>
-#endif
-#if HAVE_GETPROCESSAFFINITYMASK
-#include <windows.h>
-#endif
-#if HAVE_SYSCTL
-#if HAVE_SYS_PARAM_H
-#include <sys/param.h>
-#endif
-#include <sys/types.h>
-#include <sys/sysctl.h>
-#endif
-#if HAVE_SYSCONF
-#include <unistd.h>
-#endif
-
 #include "avcodec.h"
 #include "internal.h"
 #include "thread.h"
 #include "libavutil/avassert.h"
 #include "libavutil/common.h"
+#include "libavutil/cpu.h"
 
 #if HAVE_PTHREADS
 #include <pthread.h>
@@ -153,40 +136,6 @@ typedef struct FrameThreadContext {
  * limit the number of threads to 16 for automatic detection */
 #define MAX_AUTO_THREADS 16
 
-static int get_logical_cpus(AVCodecContext *avctx)
-{
-    int ret, nb_cpus = 1;
-#if HAVE_SCHED_GETAFFINITY && defined(CPU_COUNT)
-    cpu_set_t cpuset;
-
-    CPU_ZERO(&cpuset);
-
-    ret = sched_getaffinity(0, sizeof(cpuset), &cpuset);
-    if (!ret) {
-        nb_cpus = CPU_COUNT(&cpuset);
-    }
-#elif HAVE_GETPROCESSAFFINITYMASK
-    DWORD_PTR proc_aff, sys_aff;
-    ret = GetProcessAffinityMask(GetCurrentProcess(), &proc_aff, &sys_aff);
-    if (ret)
-        nb_cpus = av_popcount64(proc_aff);
-#elif HAVE_SYSCTL && defined(HW_NCPU)
-    int mib[2] = { CTL_HW, HW_NCPU };
-    size_t len = sizeof(nb_cpus);
-
-    ret = sysctl(mib, 2, &nb_cpus, &len, NULL, 0);
-    if (ret == -1)
-        nb_cpus = 0;
-#elif HAVE_SYSCONF && defined(_SC_NPROC_ONLN)
-    nb_cpus = sysconf(_SC_NPROC_ONLN);
-#elif HAVE_SYSCONF && defined(_SC_NPROCESSORS_ONLN)
-    nb_cpus = sysconf(_SC_NPROCESSORS_ONLN);
-#endif
-    av_log(avctx, AV_LOG_DEBUG, "detected %d logical cores\n", nb_cpus);
-    return nb_cpus;
-}
-
-
 static void* attribute_align_arg worker(void *v)
 {
     AVCodecContext *avctx = v;
@@ -292,7 +241,8 @@ static int thread_init(AVCodecContext *avctx)
     int thread_count = avctx->thread_count;
 
     if (!thread_count) {
-        int nb_cpus = get_logical_cpus(avctx);
+        int nb_cpus = av_cpu_count();
+        av_log(avctx, AV_LOG_DEBUG, "detected %d logical cores\n", nb_cpus);
         // use number of cores + 1 as thread count if there is more than one
         if (nb_cpus > 1)
             thread_count = avctx->thread_count = FFMIN(nb_cpus + 1, MAX_AUTO_THREADS);
@@ -790,7 +740,8 @@ static int frame_thread_init(AVCodecContext *avctx)
     int i, err = 0;
 
     if (!thread_count) {
-        int nb_cpus = get_logical_cpus(avctx);
+        int nb_cpus = av_cpu_count();
+        av_log(avctx, AV_LOG_DEBUG, "detected %d logical cores\n", nb_cpus);
         // use number of cores + 1 as thread count if there is more than one
         if (nb_cpus > 1)
             thread_count = avctx->thread_count = FFMIN(nb_cpus + 1, MAX_AUTO_THREADS);

libavutil/cpu.c

@@ -20,6 +20,24 @@
 #include "config.h"
 #include "opt.h"
 
+#if HAVE_SCHED_GETAFFINITY
+#define _GNU_SOURCE
+#include <sched.h>
+#endif
+#if HAVE_GETPROCESSAFFINITYMASK
+#include <windows.h>
+#endif
+#if HAVE_SYSCTL
+#if HAVE_SYS_PARAM_H
+#include <sys/param.h>
+#endif
+#include <sys/types.h>
+#include <sys/sysctl.h>
+#endif
+#if HAVE_SYSCONF
+#include <unistd.h>
+#endif
+
 static int cpuflags_mask = -1, checked;
 
 int av_get_cpu_flags(void)
@@ -109,6 +127,39 @@ int av_parse_cpu_flags(const char *s)
     return flags & INT_MAX;
 }
 
+int av_cpu_count(void)
+{
+    int ret, nb_cpus = 1;
+#if HAVE_SCHED_GETAFFINITY && defined(CPU_COUNT)
+    cpu_set_t cpuset;
+
+    CPU_ZERO(&cpuset);
+
+    ret = sched_getaffinity(0, sizeof(cpuset), &cpuset);
+    if (!ret) {
+        nb_cpus = CPU_COUNT(&cpuset);
+    }
+#elif HAVE_GETPROCESSAFFINITYMASK
+    DWORD_PTR proc_aff, sys_aff;
+    ret = GetProcessAffinityMask(GetCurrentProcess(), &proc_aff, &sys_aff);
+    if (ret)
+        nb_cpus = av_popcount64(proc_aff);
+#elif HAVE_SYSCTL && defined(HW_NCPU)
+    int mib[2] = { CTL_HW, HW_NCPU };
+    size_t len = sizeof(nb_cpus);
+
+    ret = sysctl(mib, 2, &nb_cpus, &len, NULL, 0);
+    if (ret == -1)
+        nb_cpus = 0;
+#elif HAVE_SYSCONF && defined(_SC_NPROC_ONLN)
+    nb_cpus = sysconf(_SC_NPROC_ONLN);
+#elif HAVE_SYSCONF && defined(_SC_NPROCESSORS_ONLN)
+    nb_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+#endif
+
+    return nb_cpus;
+}
+
 #ifdef TEST
 
 #include <stdio.h>

libavutil/cpu.h

@@ -76,6 +76,11 @@ void av_set_cpu_flags_mask(int mask);
  */
 int av_parse_cpu_flags(const char *s);
 
+/**
+ * @return the number of logical CPU cores present.
+ */
+int av_cpu_count(void);
+
 /* The following CPU-specific functions shall not be called directly. */
 int ff_get_cpu_flags_arm(void);
 int ff_get_cpu_flags_ppc(void);

libavutil/version.h

@@ -37,7 +37,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 52
-#define LIBAVUTIL_VERSION_MINOR 11
+#define LIBAVUTIL_VERSION_MINOR 12
 #define LIBAVUTIL_VERSION_MICRO  0
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \