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#ifndef _BENCHMARK_H_
#define _BENCHMARK_H_
#include <stdint.h>
#include <time.h>
#ifdef __x86_64__
const char *unitname = "cycles";
#define RDTSC_START(cycles) \
do { \
uint32_t cyc_high, cyc_low; \
__asm volatile("cpuid\n" \
"rdtsc\n" \
"mov %%edx, %0\n" \
"mov %%eax, %1" \
: "=r"(cyc_high), "=r"(cyc_low) \
: \
: /* no read only */ \
"%rax", "%rbx", "%rcx", "%rdx" /* clobbers */ \
); \
(cycles) = ((uint64_t)cyc_high << 32) | cyc_low; \
} while (0)
#define RDTSC_STOP(cycles) \
do { \
uint32_t cyc_high, cyc_low; \
__asm volatile("rdtscp\n" \
"mov %%edx, %0\n" \
"mov %%eax, %1\n" \
"cpuid" \
: "=r"(cyc_high), "=r"(cyc_low) \
: /* no read only registers */ \
: "%rax", "%rbx", "%rcx", "%rdx" /* clobbers */ \
); \
(cycles) = ((uint64_t)cyc_high << 32) | cyc_low; \
} while (0)
#else
const char *unitname = " (clock units) ";
#define RDTSC_START(cycles) \
do { \
cycles = clock(); \
} while (0)
#define RDTSC_STOP(cycles) \
do { \
cycles = clock(); \
} while (0)
#endif
static __attribute__((noinline)) uint64_t rdtsc_overhead_func(uint64_t dummy) {
return dummy;
}
uint64_t global_rdtsc_overhead = (uint64_t)UINT64_MAX;
#define RDTSC_SET_OVERHEAD(test, repeat) \
do { \
uint64_t cycles_start, cycles_final, cycles_diff; \
uint64_t min_diff = UINT64_MAX; \
for (int i = 0; i < repeat; i++) { \
__asm volatile("" ::: /* pretend to clobber */ "memory"); \
RDTSC_START(cycles_start); \
test; \
RDTSC_STOP(cycles_final); \
cycles_diff = (cycles_final - cycles_start); \
if (cycles_diff < min_diff) \
min_diff = cycles_diff; \
} \
global_rdtsc_overhead = min_diff; \
} while (0)
/*
* Prints the best number of operations per cycle where
* test is the function call, answer is the expected answer generated by
* test, repeat is the number of times we should repeat and size is the
* number of operations represented by test.
*/
#define BEST_TIME(test, expected, pre, repeat, size, bytes, verbose) \
do { \
if (global_rdtsc_overhead == UINT64_MAX) { \
RDTSC_SET_OVERHEAD(rdtsc_overhead_func(1), repeat); \
} \
if (verbose) \
printf("%-60s\t: ", #test); \
fflush(NULL); \
uint64_t cycles_start, cycles_final, cycles_diff; \
uint64_t min_diff = (uint64_t)-1; \
uint64_t sum_diff = 0; \
for (int i = 0; i < repeat; i++) { \
pre; \
__asm volatile("" ::: /* pretend to clobber */ "memory"); \
RDTSC_START(cycles_start); \
if (test != expected) { \
printf("not expected (%d , %d )", (int)test, (int)expected); \
break; \
} \
RDTSC_STOP(cycles_final); \
cycles_diff = (cycles_final - cycles_start - global_rdtsc_overhead); \
if (cycles_diff < min_diff) \
min_diff = cycles_diff; \
sum_diff += cycles_diff; \
} \
uint64_t S = size; \
float cycle_per_op = (min_diff) / (double)S; \
float bytes_per_cycle = (double)bytes / (min_diff); \
float avg_cycle_per_op = (sum_diff) / ((double)S * repeat); \
if (verbose) \
printf(" %.3f %s per operation (best) ", cycle_per_op, unitname); \
if (verbose) \
printf(" %.3f bytes per cycle (best) ", bytes_per_cycle); \
if (verbose) \
printf("\t%.3f %s per operation (avg) ", avg_cycle_per_op, unitname); \
if (verbose) \
printf("\n"); \
if (!verbose) \
printf(" %.3f (%.3f) ", cycle_per_op,bytes_per_cycle); \
fflush(NULL); \
} while (0)
// like BEST_TIME, but no check
#define BEST_TIME_NOCHECK(test, pre, repeat, size, verbose) \
do { \
if (global_rdtsc_overhead == UINT64_MAX) { \
RDTSC_SET_OVERHEAD(rdtsc_overhead_func(1), repeat); \
} \
if (verbose) \
printf("%-20s\t: ", #test); \
fflush(NULL); \
uint64_t cycles_start, cycles_final, cycles_diff; \
uint64_t min_diff = (uint64_t)-1; \
uint64_t sum_diff = 0; \
for (int i = 0; i < repeat; i++) { \
pre; \
__asm volatile("" ::: /* pretend to clobber */ "memory"); \
RDTSC_START(cycles_start); \
test; \
RDTSC_STOP(cycles_final); \
cycles_diff = (cycles_final - cycles_start - global_rdtsc_overhead); \
if (cycles_diff < min_diff) \
min_diff = cycles_diff; \
sum_diff += cycles_diff; \
} \
uint64_t S = size; \
float cycle_per_op = (min_diff) / (double)S; \
float avg_cycle_per_op = (sum_diff) / ((double)S * repeat); \
if (verbose) \
printf(" %.3f %s per operation (best) ", cycle_per_op, unitname); \
if (verbose) \
printf("\n"); \
if (!verbose) \
printf(" %.3f ", cycle_per_op); \
fflush(NULL); \
} while (0)
// like BEST_TIME except that we run a function to check the result
#define BEST_TIME_CHECK(test, check, pre, repeat, size, verbose) \
do { \
if (global_rdtsc_overhead == UINT64_MAX) { \
RDTSC_SET_OVERHEAD(rdtsc_overhead_func(1), repeat); \
} \
if (verbose) \
printf("%-60s\t: ", #test); \
fflush(NULL); \
uint64_t cycles_start, cycles_final, cycles_diff; \
uint64_t min_diff = (uint64_t)-1; \
uint64_t sum_diff = 0; \
for (int i = 0; i < repeat; i++) { \
pre; \
__asm volatile("" ::: /* pretend to clobber */ "memory"); \
RDTSC_START(cycles_start); \
test; \
RDTSC_STOP(cycles_final); \
if (!check) { \
printf("error"); \
break; \
} \
cycles_diff = (cycles_final - cycles_start - global_rdtsc_overhead); \
if (cycles_diff < min_diff) \
min_diff = cycles_diff; \
sum_diff += cycles_diff; \
} \
uint64_t S = size; \
float cycle_per_op = (min_diff) / (double)S; \
float avg_cycle_per_op = (sum_diff) / ((double)S * repeat); \
if (verbose) \
printf(" %.3f cycles per operation (best) ", cycle_per_op); \
if (verbose) \
printf("\t%.3f cycles per operation (avg) ", avg_cycle_per_op); \
if (verbose) \
printf("\n"); \
if (!verbose) \
printf(" %.3f ", cycle_per_op); \
fflush(NULL); \
} while (0)
#endif