some benchmarking code

Originally committed as revision 1901 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/libavcodec/common.h b/libavcodec/common.h
index e83d277033ddf389626a5b053b6df7d86aa7aa5e..bbbc613dd2f5fb26f59773f934ea4dd27684f89a 100644 (file)
--- a/libavcodec/common.h
+++ b/libavcodec/common.h
@@ -1090,6 +1090,35 @@ if((y)<(x)){\
 }
 #endif
 
+#ifdef ARCH_X86
+static inline long long rdtsc()
+{
+       long long l;
+       asm volatile(   "rdtsc\n\t"
+               : "=A" (l)
+       );
+       return l;
+}
+
+#define START_TIMER \
+static uint64_t tsum=0;\
+static int tcount=0;\
+static int tskip_count=0;\
+uint64_t tend;\
+uint64_t tstart= rdtsc();\
+
+#define STOP_TIMER(id) \
+tend= rdtsc();\
+if(tcount<2 || tend - tstart < 4*tsum/tcount){\
+    tsum+= tend - tstart;\
+    tcount++;\
+}else\
+    tskip_count++;\
+if(256*256*256*64%(tcount+tskip_count)==0){\
+    fprintf(stderr, "%Ld dezicycles in %s, %d runs, %d skips\n", tsum*10/tcount, id, tcount, tskip_count);\
+}
+#endif
+
 #define CLAMP_TO_8BIT(d) ((d > 0xff) ? 0xff : (d < 0) ? 0 : d)
 
 /* avoid usage of various functions */