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comparison demo/benchmark.c @ 0:e38dacceb958

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author Robert McIntyre <rlm@mit.edu>
date Fri, 21 Oct 2011 05:53:11 -0700
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-1:000000000000 0:e38dacceb958
1 /* Measures performance of SPC emulator. Takes about 4 seconds.
2 NOTE: This assumes that the program is getting all processor time; you might need to
3 arrange for this or else the performance will be reported lower than it really is.
4
5 Usage: benchmark [test.spc]
6 */
7
8 #include "snes_spc/spc.h"
9
10 #include "demo_util.h" /* error(), load_file() */
11 #include <time.h>
12
13 clock_t start_timing( int seconds );
14
15 int main( int argc, char** argv )
16 {
17 /* Load SPC */
18 long spc_size;
19 void* spc = load_file( (argc > 1) ? argv [1] : "test.spc", &spc_size );
20 SNES_SPC* snes_spc = spc_new();
21 if ( !snes_spc ) error( "Out of memory" );
22 spc_load_spc( snes_spc, spc, spc_size );
23 free( spc );
24
25 {
26 /* Repeatedly fill buffer for 4 seconds */
27 int const seconds = 4;
28 #define BUF_SIZE 4096
29 clock_t end = start_timing( seconds );
30 int count = 0;
31 while ( clock() < end )
32 {
33 static short buf [BUF_SIZE];
34 error( spc_play( snes_spc, BUF_SIZE, buf ) );
35 count++;
36 }
37
38 /* Report performance based on how many buffer fills were possible */
39 {
40 double rate = (double) count * BUF_SIZE / (spc_sample_rate * 2 * seconds);
41 printf( "Performance: %.3fx real-time, or %.0f%% CPU for normal rate\n",
42 rate, 100.0 / rate );
43 }
44 }
45
46 return 0;
47 }
48
49 /* Synchronizes with host clock and returns clock() time that is duration seconds from now */
50 clock_t start_timing( int duration )
51 {
52 clock_t clock_dur = duration * CLOCKS_PER_SEC;
53 clock_t time = clock();
54 while ( clock() == time ) { }
55 if ( clock() - time > clock_dur )
56 error( "Insufficient clock() time resolution" );
57 return clock() + clock_dur;
58 }