/* Copyright (c) 2016 Facebook

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of version 2 of the GNU General Public

 * License as published by the Free Software Foundation.

 */

#define _GNU_SOURCE

#include <sched.h>

#include <errno.h>

#include <stdio.h>

#include <sys/types.h>

#include <asm/unistd.h>

#include <fcntl.h>

#include <unistd.h>

#include <assert.h>

#include <sys/wait.h>

#include <stdlib.h>

#include <signal.h>

#include <linux/bpf.h>

#include <string.h>

#include <time.h>

#include <sys/resource.h>

#include <bpf/bpf.h>

#include "bpf_load.h"

#define MAX_CNT 1000000

static __u64 time_get_ns(void)

{

	struct timespec ts;

	clock_gettime(CLOCK_MONOTONIC, &ts);

	return ts.tv_sec * 1000000000ull + ts.tv_nsec;

}

static void test_task_rename(int cpu)

{

	__u64 start_time;

	char buf[] = "test\n";

	int i, fd;

	fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);

	if (fd < 0) {

		printf("couldn't open /proc\n");

		exit(1);

	}

	start_time = time_get_ns();

	for (i = 0; i < MAX_CNT; i++) {

		if (write(fd, buf, sizeof(buf)) < 0) {

			printf("task rename failed: %s\n", strerror(errno));

			close(fd);

			return;

		}

	}

	printf("task_rename:%d: %lld events per sec\n",

	       cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));

	close(fd);

}

static void test_urandom_read(int cpu)

{

	__u64 start_time;

	char buf[4];

	int i, fd;

	fd = open("/dev/urandom", O_RDONLY);

	if (fd < 0) {

		printf("couldn't open /dev/urandom\n");

		exit(1);

	}

	start_time = time_get_ns();

	for (i = 0; i < MAX_CNT; i++) {

		if (read(fd, buf, sizeof(buf)) < 0) {

			printf("failed to read from /dev/urandom: %s\n", strerror(errno));

			close(fd);

			return;

		}

	}

	printf("urandom_read:%d: %lld events per sec\n",

	       cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));

	close(fd);

}

static void loop(int cpu, int flags)

{

	cpu_set_t cpuset;

	CPU_ZERO(&cpuset);

	CPU_SET(cpu, &cpuset);

	sched_setaffinity(0, sizeof(cpuset), &cpuset);

	if (flags & 1)

		test_task_rename(cpu);

	if (flags & 2)

		test_urandom_read(cpu);

}

static void run_perf_test(int tasks, int flags)

{

	pid_t pid[tasks];

	int i;

	for (i = 0; i < tasks; i++) {

		pid[i] = fork();

		if (pid[i] == 0) {

			loop(i, flags);

			exit(0);

		} else if (pid[i] == -1) {

			printf("couldn't spawn #%d process\n", i);

			exit(1);

		}

	}

	for (i = 0; i < tasks; i++) {

		int status;

		assert(waitpid(pid[i], &status, 0) == pid[i]);

		assert(status == 0);

	}

}

static void unload_progs(void)

{

	close(prog_fd[0]);

	close(prog_fd[1]);

	close(event_fd[0]);

	close(event_fd[1]);

}

int main(int argc, char **argv)

{

	struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};

	char filename[256];

	int num_cpu = 8;

	int test_flags = ~0;

	setrlimit(RLIMIT_MEMLOCK, &r);

	if (argc > 1)

		test_flags = atoi(argv[1]) ? : test_flags;

	if (argc > 2)

		num_cpu = atoi(argv[2]) ? : num_cpu;

	if (test_flags & 0x3) {

		printf("BASE\n");

		run_perf_test(num_cpu, test_flags);

	}

	if (test_flags & 0xC) {

		snprintf(filename, sizeof(filename),

			 "%s_kprobe_kern.o", argv[0]);

		if (load_bpf_file(filename)) {

			printf("%s", bpf_log_buf);

			return 1;

		}

		printf("w/KPROBE\n");

		run_perf_test(num_cpu, test_flags >> 2);

		unload_progs();

	}

	if (test_flags & 0x30) {

		snprintf(filename, sizeof(filename),

			 "%s_tp_kern.o", argv[0]);

		if (load_bpf_file(filename)) {

			printf("%s", bpf_log_buf);

			return 1;

		}

		printf("w/TRACEPOINT\n");

		run_perf_test(num_cpu, test_flags >> 4);

		unload_progs();

	}

	if (test_flags & 0xC0) {

		snprintf(filename, sizeof(filename),

			 "%s_raw_tp_kern.o", argv[0]);

		if (load_bpf_file(filename)) {

			printf("%s", bpf_log_buf);

			return 1;

		}

		printf("w/RAW_TRACEPOINT\n");

		run_perf_test(num_cpu, test_flags >> 6);

		unload_progs();

	}

	return 0;

}