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PEP 418: Patch bench_time.c to support systems without clock_gettime()

This commit is contained in:
Victor Stinner 2012-04-19 23:26:51 +02:00
parent a0e363488b
commit bfcd81b80e
1 changed files with 37 additions and 10 deletions
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47
pep-0418/bench_time.c
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@ -8,12 +8,20 @@
#include <stdio.h> #include <stdio.h>
#include <sys/time.h> #include <sys/time.h>
#ifdef CLOCK_REALTIME
# define HAVE_CLOCK_GETTIME
#else
typedef int clockid_t;
#endif
#define NRUN 5 #define NRUN 5
#define NLOOP 1000000 #define NLOOP 100000
#define UNROLL(expr) \ #define UNROLL(expr) \
expr; expr; expr; expr; expr; expr; expr; expr; expr; expr expr; expr; expr; expr; expr; expr; expr; expr; expr; expr
#define NUNROLL 10 #define NUNROLL 10
#ifdef HAVE_CLOCK_GETTIME
typedef struct { typedef struct {
const char *name; const char *name;
clockid_t identifier; clockid_t identifier;
@ -80,6 +88,8 @@ void bench_clock_gettime(clockid_t clkid)
} }
} }
#endif /* HAVE_CLOCK_GETTIME */
void bench_time(clockid_t clkid) void bench_time(clockid_t clkid)
{ {
unsigned long loop; unsigned long loop;
@ -117,25 +127,40 @@ void benchmark(const char *name, void (*func) (clockid_t clkid), clockid_t clkid
{ {
unsigned int run; unsigned int run;
double dt, best; double dt, best;
struct timespec before, after, tmpspec; #ifdef HAVE_CLOCK_GETTIME
struct timespec before, after;
#else
struct timeval before, after;
#endif
struct timeval tmpval; struct timeval tmpval;
best = 0; best = -1.0;
for (run=0; run<NRUN; run++) { for (run=0; run<NRUN; run++) {
#ifdef HAVE_CLOCK_GETTIME
clock_gettime(CLOCK_MONOTONIC, &before); clock_gettime(CLOCK_MONOTONIC, &before);
(*func) (clkid); (*func) (clkid);
clock_gettime(CLOCK_MONOTONIC, &after); clock_gettime(CLOCK_MONOTONIC, &after);
dt = after.tv_sec - before.tv_sec; dt = (after.tv_sec - before.tv_sec) * 1e9;
if (after.tv_nsec >= before.tv_nsec) if (after.tv_nsec >= before.tv_nsec)
dt += (after.tv_nsec - before.tv_nsec) * 1e-9; dt += (after.tv_nsec - before.tv_nsec);
else else
{ dt -= (before.tv_nsec - after.tv_nsec);
dt -= (before.tv_nsec - after.tv_nsec) * 1e-9; #else
} gettimeofday(&before, NULL);
dt *= (double)1e9 / NLOOP / NUNROLL; (*func) (clkid);
gettimeofday(&after, NULL);
if (best != 0.0) { dt = (after.tv_sec - before.tv_sec) * 1e9;
if (after.tv_usec >= before.tv_usec)
dt += (after.tv_usec - before.tv_usec) * 1e3;
else
dt -= (before.tv_usec - after.tv_usec) * 1e3;
#endif
dt /= NLOOP;
dt /= NUNROLL;
if (best != -1.0) {
if (dt < best) if (dt < best)
best = dt; best = dt;
} }
@ -147,12 +172,14 @@ void benchmark(const char *name, void (*func) (clockid_t clkid), clockid_t clkid
int main() int main()
{ {
#ifdef HAVE_CLOCK_GETTIME
clockid_t clkid; clockid_t clkid;
int i; int i;
for (i=0; i<NCLOCKS; i++) { for (i=0; i<NCLOCKS; i++) {
benchmark(clocks[i].name, bench_clock_gettime, clocks[i].identifier); benchmark(clocks[i].name, bench_clock_gettime, clocks[i].identifier);
} }
#endif
benchmark("clock()", bench_clock, 0); benchmark("clock()", bench_clock, 0);
benchmark("gettimeofday()", bench_gettimeofday, 0); benchmark("gettimeofday()", bench_gettimeofday, 0);
benchmark("time()", bench_time, 0); benchmark("time()", bench_time, 0);