strcmp-benchmark/bench.c at master · linux-ia64/strcmp-benchmark · GitHub

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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#define algn __attribute__ ((aligned (8)))
#define NITER 40000000
#define MULTIPLIER 1

#define PIECE "Hello world, Itanium is not dead and will not be for a very long time."
#define PIECEA PIECE "a"
#define PIECEB PIECE "b"

#define LONG_A 	PIECEA PIECEA PIECEA
#define LONG_B	PIECEA PIECEA PIECEB
#define S16B_A "HELLOWOA"
#define S16B_B "HELLOWOB"

#ifdef USE_STRNCMP
#define FN "strncmp"
#define CMPFN(a, b) strncmp(a, b, sizeof(b))
#else
#define FN "strcmp"
#define CMPFN(a, b) strcmp(a, b)
#endif

double iter_per_msec(struct timespec *a, struct timespec *b, int multiplier)
{
	double time = (b->tv_sec * 1000.0 + b->tv_nsec / 1000000.0) - (a->tv_sec * 1000.0 + a->tv_nsec / 1000000.0);
	return (NITER * multiplier) / time;
}

#define PAIR(name, left, right) \
	char name##_align_a[] algn = left;\
	char name##_align_b[] algn = right;\
	char name##_noalign_a_[] algn = " " left;\
	char name##_noalign_b_[] algn = " " right;\
	char *name##_noalign_a = name##_noalign_a_ + 1;\
	char *name##_noalign_b = name##_noalign_b_ + 1;

PAIR(long_equal, LONG_A, LONG_A)
PAIR(long_nonequal, LONG_A, LONG_B)
PAIR(s16b_equal, S16B_A, S16B_A)
PAIR(s16b_nonequal, S16B_A, S16B_B)
PAIR(one_char_eq, "a", "a")
PAIR(one_char_neq, "a" PIECE, "b" PIECE)
PAIR(two_char_neq, "aa" PIECE, "ab" PIECE)
PAIR(three_char_neq, "aaa" PIECE, "aab" PIECE)
PAIR(four_char_neq, "aaaa" PIECE, "aaab" PIECE)

#define CASE(name, expected_result) do {\
	x = CMPFN(name##_a, name##_b);\
	if (x > 0)\
		x = 1;\
	else if (x < 0)\
		x = -1;\
	if (x != expected_result) {\
		printf("ERROR! Mismatch on " #name ": expected %d, got %d!\n", expected_result, x);\
		exit(1);\
	}\
	clock_gettime(CLOCK_MONOTONIC, &before);\
	for (i = 0; i < NITER * MULTIPLIER; i++) {\
		x = CMPFN(name##_a, name##_b);\
	}\
	clock_gettime(CLOCK_MONOTONIC, &after);\
	printf(#name ":\t%f iter/msec\n", iter_per_msec(&before, &after, MULTIPLIER));\
} while (0);

#ifdef USE_STRNCMP
#define CASES(name, expected_result) do {\
	CASE(name##_align, expected_result)\
} while (0);
#else
#define CASES(name, expected_result) do {\
	CASE(name##_align, expected_result)\
	CASE(name##_noalign, expected_result)\
} while (0);
#endif

int main()
{
	unsigned long i;
	volatile int x __attribute__ ((unused));
	struct timespec before, after;

	printf("Versatile libc " FN "() benchmark for 64-bit machines\n");
	printf("By: EPIC Linux project, http://www.epic-linux.org\n");
	printf("\n");

	CASES(long_equal, 0)
	CASES(long_nonequal, -1)
#undef MULTIPLIER
#define MULTIPLIER 10
	CASES(s16b_equal, 0)
	CASES(s16b_nonequal, -1)
	CASES(one_char_eq, 0)
	CASES(one_char_neq, -1)
	CASES(two_char_neq, -1)
	CASES(three_char_neq, -1)
	CASES(four_char_neq, -1)
}