From cf6cf50ac689e3dc69c54b66495cd4951105bf61 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 6 Dec 2013 15:24:10 +0100 Subject: [PATCH] do O(1) instead of O(n) atomic operations in register functions about 1ms faster startup time Signed-off-by: Michael Niedermayer (cherry picked from commit 133fbfc7811ffae7b97dd129fcd0b5e646742362) Signed-off-by: Michael Niedermayer --- libavcodec/utils.c | 5 +++-- libavfilter/avfilter.c | 2 +- libavformat/format.c | 4 ++-- 3 files changed, 6 insertions(+), 5 deletions(-) diff --git a/libavcodec/utils.c b/libavcodec/utils.c index ae32a35b87..554b30edbf 100644 --- a/libavcodec/utils.c +++ b/libavcodec/utils.c @@ -218,7 +218,8 @@ av_cold void avcodec_register(AVCodec *codec) avcodec_init(); p = &first_avcodec; codec->next = NULL; - while(avpriv_atomic_ptr_cas((void * volatile *)p, NULL, codec)) + + while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, codec)) p = &(*p)->next; if (codec->init_static_data) @@ -3182,7 +3183,7 @@ void av_register_hwaccel(AVHWAccel *hwaccel) { AVHWAccel **p = &first_hwaccel; hwaccel->next = NULL; - while(avpriv_atomic_ptr_cas((void * volatile *)p, NULL, hwaccel)) + while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, hwaccel)) p = &(*p)->next; } diff --git a/libavfilter/avfilter.c b/libavfilter/avfilter.c index f31968f394..c9c8accc2a 100644 --- a/libavfilter/avfilter.c +++ b/libavfilter/avfilter.c @@ -487,7 +487,7 @@ int avfilter_register(AVFilter *filter) filter->next = NULL; - while(avpriv_atomic_ptr_cas((void * volatile *)f, NULL, filter)) + while(*f || avpriv_atomic_ptr_cas((void * volatile *)f, NULL, filter)) f = &(*f)->next; return 0; diff --git a/libavformat/format.c b/libavformat/format.c index ac9100b604..36c0131c12 100644 --- a/libavformat/format.c +++ b/libavformat/format.c @@ -54,7 +54,7 @@ void av_register_input_format(AVInputFormat *format) AVInputFormat **p = &first_iformat; format->next = NULL; - while(avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format)) + while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format)) p = &(*p)->next; } @@ -63,7 +63,7 @@ void av_register_output_format(AVOutputFormat *format) AVOutputFormat **p = &first_oformat; format->next = NULL; - while(avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format)) + while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, format)) p = &(*p)->next; }