selftests/seccomp: Improve calibration loop (81a0c8bc) · Commits · 戴 / test

tools/testing/selftests/seccomp/seccomp_benchmark.c

+32 −18

Original line number	Diff line number	Diff line
		@@ -18,9 +18,9 @@

		unsigned long long timing(clockid_t clk_id, unsigned long long samples)
		{
		pid_t pid, ret;
		unsigned long long i;
		struct timespec start, finish;
		unsigned long long i;
		pid_t pid, ret;

		pid = getpid();
		assert(clock_gettime(clk_id, &start) == 0);
		@@ -31,30 +31,43 @@ unsigned long long timing(clockid_t clk_id, unsigned long long samples)
		assert(clock_gettime(clk_id, &finish) == 0);

		i = finish.tv_sec - start.tv_sec;
		i *= 1000000000;
		i *= 1000000000ULL;
		i += finish.tv_nsec - start.tv_nsec;

		printf("%lu.%09lu - %lu.%09lu = %llu\n",
		printf("%lu.%09lu - %lu.%09lu = %llu (%.1fs)\n",
		finish.tv_sec, finish.tv_nsec,
		start.tv_sec, start.tv_nsec,
		i);
		i, (double)i / 1000000000.0);

		return i;
		}

		unsigned long long calibrate(void)
		{
		unsigned long long i;

		printf("Calibrating reasonable sample size...\n");
		struct timespec start, finish;
		unsigned long long i, samples, step = 9973;
		pid_t pid, ret;
		int seconds = 15;

		for (i = 5; ; i++) {
		unsigned long long samples = 1 << i;
		printf("Calibrating sample size for %d seconds worth of syscalls ...\n", seconds);

		/* Find something that takes more than 5 seconds to run. */
		if (timing(CLOCK_REALTIME, samples) / 1000000000ULL > 5)
		return samples;
		samples = 0;
		pid = getpid();
		assert(clock_gettime(CLOCK_MONOTONIC, &start) == 0);
		do {
		for (i = 0; i < step; i++) {
		ret = syscall(__NR_getpid);
		assert(pid == ret);
		}
		assert(clock_gettime(CLOCK_MONOTONIC, &finish) == 0);

		samples += step;
		i = finish.tv_sec - start.tv_sec;
		i *= 1000000000ULL;
		i += finish.tv_nsec - start.tv_nsec;
		} while (i < 1000000000ULL);

		return samples * seconds;
		}

		int main(int argc, char *argv[])
		@@ -70,15 +83,16 @@ int main(int argc, char *argv[])
		unsigned long long samples;
		unsigned long long native, filter1, filter2;

		printf("Current BPF sysctl settings:\n");
		system("sysctl net.core.bpf_jit_enable");
		system("sysctl net.core.bpf_jit_harden");

		if (argc > 1)
		samples = strtoull(argv[1], NULL, 0);
		else
		samples = calibrate();

		printf("Current BPF sysctl settings:\n");
		system("sysctl net.core.bpf_jit_enable");
		system("sysctl net.core.bpf_jit_harden");
		printf("Benchmarking %llu samples...\n", samples);
		printf("Benchmarking %llu syscalls...\n", samples);

		/* Native call */
		native = timing(CLOCK_PROCESS_CPUTIME_ID, samples) / samples;

Admin message