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/*
this measures the ping-pong byte range lock latency. It is
especially useful on a cluster of nodes sharing a common lock
manager as it will give some indication of the lock managers
performance under stress
tridge@samba.org, February 2002
*/
#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <time.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <getopt.h>
#include <sys/mman.h>
static struct timeval tp1,tp2;
static int do_reads, do_writes, use_mmap;
struct file_info
{
int fd;
int num_locks;
};
typedef struct file_info file_info_t;
static void start_timer()
{
gettimeofday(&tp1,NULL);
}
static double end_timer()
{
gettimeofday(&tp2,NULL);
return (tp2.tv_sec + (tp2.tv_usec*1.0e-6)) -
(tp1.tv_sec + (tp1.tv_usec*1.0e-6));
}
/* lock a byte range in a open file */
static int lock_range(int fd, int offset, int len)
{
struct flock lock;
lock.l_type = F_WRLCK;
lock.l_whence = SEEK_SET;
lock.l_start = offset;
lock.l_len = len;
lock.l_pid = 0;
return fcntl(fd,F_SETLKW,&lock);
}
/* unlock a byte range in a open file */
static int unlock_range(int fd, int offset, int len)
{
struct flock lock;
lock.l_type = F_UNLCK;
lock.l_whence = SEEK_SET;
lock.l_start = offset;
lock.l_len = len;
lock.l_pid = 0;
return fcntl(fd,F_SETLKW,&lock);
}
/* run the ping pong test on fd */
static void ping_pong(void *info)
{
file_info_t *info_file = NULL;
unsigned count = 0;
int i=0, loops=0;
unsigned char *val;
unsigned char incr=0, last_incr=0;
unsigned char *p = NULL;
int fd = -1;
int num_locks = -1;
info_file = (file_info_t *)info;
fd = info_file->fd;
num_locks = info_file->num_locks;
ftruncate(fd, num_locks+1);
if (use_mmap) {
p = mmap(NULL, num_locks+1, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
}
val = (unsigned char *)calloc(num_locks+1, sizeof(unsigned char));
start_timer();
lock_range(fd, 0, 1);
i = 0;
while (1) {
if (lock_range(fd, (i+1) % num_locks, 1) != 0) {
printf("lock at %d failed! - %s\n",
(i+1) % num_locks, strerror(errno));
}
if (do_reads) {
unsigned char c;
if (use_mmap) {
c = p[i];
} else if (pread(fd, &c, 1, i) != 1) {
printf("read failed at %d\n", i);
}
incr = c - val[i];
val[i] = c;
}
if (do_writes) {
char c = val[i] + 1;
if (use_mmap) {
p[i] = c;
} else if (pwrite(fd, &c, 1, i) != 1) {
printf("write failed at %d\n", i);
}
}
if (unlock_range(fd, i, 1) != 0) {
printf("unlock at %d failed! - %s\n",
i, strerror(errno));
}
i = (i+1) % num_locks;
count++;
if (loops > num_locks && incr != last_incr) {
last_incr = incr;
printf("data increment = %u\n", incr);
fflush(stdout);
}
if (end_timer() > 1.0) {
printf("%8u locks/sec\r",
(unsigned)(2*count/end_timer()));
fflush(stdout);
start_timer();
count=0;
}
loops++;
}
}
int main(int argc, char *argv[])
{
char *fname;
int fd, num_locks;
int c;
file_info_t info_file;
pthread_t thread;
int tid = -1;
int zzzz = 600;
while ((c = getopt(argc, argv, "rwm")) != -1) {
switch (c){
case 'w':
do_writes = 1;
break;
case 'r':
do_reads = 1;
break;
case 'm':
use_mmap = 1;
break;
default:
fprintf(stderr, "Unknown option '%c'\n", c);
exit(1);
}
}
argv += optind;
argc -= optind;
if (argc < 2) {
printf("ping_pong [options] <file> <num_locks> [run_time]\n");
printf(" -r do reads\n");
printf(" -w do writes\n");
printf(" -m use mmap\n");
exit(1);
}
fname = argv[0];
num_locks = atoi(argv[1]);
if (argv[2])
zzzz = atoi (argv[2]);
if (zzzz <= 0) {
fprintf (stderr, "Cannot sleep for 0 or -ve seconds. Defaulting to 600");
zzzz = 600;
}
fd = open(fname, O_CREAT|O_RDWR, 0600);
if (fd == -1) exit(1);
info_file.fd = fd;
info_file.num_locks = num_locks;
tid = pthread_create (&thread, NULL, (void *)ping_pong, (void *)&info_file);
sleep (zzzz);
return 0;
}
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