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benchmark.h
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benchmark.h
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#ifndef _BENCHMARK_H_
#define _BENCHMARK_H_
#include <stdint.h>
#if defined(HAVE_RVV_INSTRUCTIONS)
#define READ_CYCLES(cycles) \
do { \
uint64_t tmp{0}; \
__asm volatile("csrr %0, cycle\n" \
: "=r" (tmp) \
); \
(cycles) = tmp; \
} while (0)
#else // x86 code
#define READ_CYCLES(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)
#endif
#define RDTSC_START(cycles) READ_CYCLES(cycles)
#define RDTSC_STOP(cycles) READ_CYCLES(cycles)
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 (unsigned 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; \
printf("rdtsc_overhead set to %d\n", (int)global_rdtsc_overhead); \
} 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(pre, test, test_name, repeat, size) \
do { \
if (global_rdtsc_overhead == UINT64_MAX) { \
RDTSC_SET_OVERHEAD(rdtsc_overhead_func(1), repeat); \
} \
printf("%-30s\t: ", test_name); fflush(stdout); \
uint64_t cycles_start, cycles_final, cycles_diff; \
uint64_t min_diff = (uint64_t)-1; \
uint64_t sum_diff = 0; \
for (size_t 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); \
printf(" %8.3f cycle/op (best) %8.3f cycle/op (avg)\n", cycle_per_op, avg_cycle_per_op); \
} while (0)
#endif