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linux: use number of CPUs as automatic thread count

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Use sched_getaffinity to determine the number of logical CPUs.
Limits the number of threads to 16 since slice threading of H.264
seems to be buggy with more than 16 threads.
This commit is contained in:
Janne Grunau 2011-12-21 01:18:01 +01:00
parent f77f640b30
commit ea4d5f4837
2 changed files with 45 additions and 0 deletions
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2
configure vendored
View File

@ -1117,6 +1117,7 @@ HAVE_LIST="
posix_memalign
round
roundf
sched_getaffinity
sdl
sdl_video_size
setmode
@ -2853,6 +2854,7 @@ check_func setrlimit
check_func strerror_r
check_func strptime
check_func strtok_r
check_func sched_getaffinity
check_func_headers io.h setmode
check_func_headers lzo/lzo1x.h lzo1x_999_compress
check_lib2 "windows.h psapi.h" GetProcessMemoryInfo -lpsapi

43
libavcodec/pthread.c
View File

@ -30,6 +30,12 @@
*/
#include "config.h"
#if HAVE_SCHED_GETAFFINITY
#define _GNU_SOURCE
#include <sched.h>
#endif
#include "avcodec.h"
#include "internal.h"
#include "thread.h"
@ -133,6 +139,29 @@ typedef struct FrameThreadContext {
int die; ///< Set when threads should exit.
} FrameThreadContext;
/* H264 slice threading seems to be buggy with more than 16 threads,
* 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
cpu_set_t cpuset;
CPU_ZERO(&cpuset);
ret = sched_getaffinity(0, sizeof(cpuset), &cpuset);
if (!ret) {
nb_cpus = CPU_COUNT(&cpuset);
}
#endif
av_log(avctx, AV_LOG_DEBUG, "detected %d logical cores\n", nb_cpus);
return FFMIN(nb_cpus, MAX_AUTO_THREADS);
}
static void* attribute_align_arg worker(void *v)
{
AVCodecContext *avctx = v;
@ -237,6 +266,13 @@ static int thread_init(AVCodecContext *avctx)
ThreadContext *c;
int thread_count = avctx->thread_count;
if (!thread_count) {
int nb_cpus = get_logical_cpus(avctx);
// use number of cores + 1 as thread count if there is motre than one
if (nb_cpus > 1)
thread_count = avctx->thread_count = nb_cpus + 1;
}
if (thread_count <= 1) {
avctx->active_thread_type = 0;
return 0;
@ -697,6 +733,13 @@ static int frame_thread_init(AVCodecContext *avctx)
FrameThreadContext *fctx;
int i, err = 0;
if (!thread_count) {
int nb_cpus = get_logical_cpus(avctx);
// use number of cores + 1 as thread count if there is motre than one
if (nb_cpus > 1)
thread_count = avctx->thread_count = nb_cpus + 1;
}
if (thread_count <= 1) {
avctx->active_thread_type = 0;
return 0;