sitano/mmap.c

## mmap.c
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdbool.h>
#include <stdint.h>
#include <pthread.h>

#define handle_error_en(en, msg) \
       do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)

#define handle_error(msg) \
       do { perror(msg); exit(EXIT_FAILURE); } while (0)

void errExit(const char *str) {
  printf("error: %s\n", str);
  exit(1);
}

struct task {
	pthread_t tid;
	char *addr;
	off_t size;
};

static void *
thread_start(void *arg) {
  struct task *t = arg;
  size_t x = 0;

  srand(t->tid);

  printf("firing at %p+%ld\n", t->addr, t->size);

  while (1) {
    off_t off = (rand() % t->size);
    x += *(t->addr + off);
    if (rand() % 100 < 1) {
	    t->addr[off] ++;
    }
  }

  return (void *)x;
}

int
main(int argc, char *argv[]) {
  char *addr, *base;
  int fd;
  struct stat sb;
  const size_t threads = 4;
  struct task ptt[threads] = {};

  if (argc != 2 || strcmp(argv[1], "--help") == 0)
    errExit("invalid file");

  fd = open(argv[1], O_RDONLY);
  if (fd == -1)
    errExit("open");

  if (fstat(fd, &sb) == -1)
   errExit("fstat");

  base = addr = mmap(NULL, sb.st_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0);
  if (addr == MAP_FAILED)
    errExit("mmap");

  printf("mapped, addr = %p, size = %ld\n", base, sb.st_size);

  off_t size = 1ll << 29;
  for (size_t i = 0; i < threads; i ++) {
	ptt[i].addr = addr + (rand() % (sb.st_size / size)) * size;
	// ptt[i].addr = addr;
	ptt[i].size = size;
	int s = pthread_create(&ptt[i].tid, NULL, &thread_start, &ptt[i]);
	if (s != 0)
          handle_error_en(s, "pthread_create");
  }

  printf("started %zu\n", threads);

  for (int i = 0; i < threads; i++) {
       void *res;
       int s = pthread_join(ptt[i].tid, &res);
       if (s != 0)
	   handle_error_en(s, "pthread_join");

       printf("Joined with thread %ld; returned value was %ld\n", ptt[i].tid, (size_t) res);
  }

  printf("done\n");

  getchar();

  exit(EXIT_SUCCESS);

  return 0;
}
	#include <errno.h>
	#include <fcntl.h>
	#include <stdio.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>
	#include <sys/mman.h>
	#include <sys/stat.h>
	#include <sys/types.h>
	#include <unistd.h>
	#include <stdbool.h>
	#include <stdint.h>
	#include <pthread.h>

	#define handle_error_en(en, msg) \
	do { errno = en; perror(msg); exit(EXIT_FAILURE); } while (0)

	#define handle_error(msg) \
	do { perror(msg); exit(EXIT_FAILURE); } while (0)

	void errExit(const char *str) {
	printf("error: %s\n", str);
	exit(1);
	}

	struct task {
	pthread_t tid;
	char *addr;
	off_t size;
	};

	static void *
	thread_start(void *arg) {
	struct task *t = arg;
	size_t x = 0;

	srand(t->tid);

	printf("firing at %p+%ld\n", t->addr, t->size);

	while (1) {
	off_t off = (rand() % t->size);
	x += *(t->addr + off);
	if (rand() % 100 < 1) {
	t->addr[off] ++;
	}
	}

	return (void *)x;
	}

	int
	main(int argc, char *argv[]) {
	char addr, base;
	int fd;
	struct stat sb;
	const size_t threads = 4;
	struct task ptt[threads] = {};

	if (argc != 2 \|\| strcmp(argv[1], "--help") == 0)
	errExit("invalid file");

	fd = open(argv[1], O_RDONLY);
	if (fd == -1)
	errExit("open");

	if (fstat(fd, &sb) == -1)
	errExit("fstat");

	base = addr = mmap(NULL, sb.st_size, PROT_READ \| PROT_WRITE, MAP_PRIVATE, fd, 0);
	if (addr == MAP_FAILED)
	errExit("mmap");

	printf("mapped, addr = %p, size = %ld\n", base, sb.st_size);

	off_t size = 1ll << 29;
	for (size_t i = 0; i < threads; i ++) {
	ptt[i].addr = addr + (rand() % (sb.st_size / size)) * size;
	// ptt[i].addr = addr;
	ptt[i].size = size;
	int s = pthread_create(&ptt[i].tid, NULL, &thread_start, &ptt[i]);
	if (s != 0)
	handle_error_en(s, "pthread_create");
	}

	printf("started %zu\n", threads);

	for (int i = 0; i < threads; i++) {
	void *res;
	int s = pthread_join(ptt[i].tid, &res);
	if (s != 0)
	handle_error_en(s, "pthread_join");

	printf("Joined with thread %ld; returned value was %ld\n", ptt[i].tid, (size_t) res);
	}

	printf("done\n");

	getchar();

	exit(EXIT_SUCCESS);

	return 0;
	}