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Posted to dev@httpd.apache.org by Dean Gaudet <dg...@arctic.org> on 1997/11/02 01:53:52 UTC
updated time-sem.c
This time-sem.c includes the necessary signal manipulations to allow us to
continue to use pthreads. It appears to still be and order of magnitude
faster than fcntl locking. I'm a little too busy to make a patch though,
so if someone could take the pthread code in time-sem.c here and compare
it against the server ... and generate a patch, that'd be great. You also
have to properly release the mutex on any of the three unblocked signals --
which you should do in the handlers we already have for those signals,
so that we don't have to also instate a handler during the critical
section ...
For our known bugs in 1.3b2 we should probably list this, workaround is
to edit conf.h and switch to FCNTL locking.
Dean
/*
gcc -o time-FCNTL -Wall -O time-sem.c -DUSE_FCNTL_SERIALIZED_ACCEPT
gcc -o time-FLOCK -Wall -O time-sem.c -DUSE_FLOCK_SERIALIZED_ACCEPT
gcc -o time-SEM -Wall -O time-sem.c -DUSE_SYSVSEM_SERIALIZED_ACCEPT
gcc -o time-PTHREAD -Wall -O time-sem.c -DUSE_PTHREAD_SERIALIZED_ACCEPT -lpthread
*/
#include <errno.h>
#include <sys/time.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/wait.h>
#include <sys/mman.h>
#include <signal.h>
#if defined(USE_FCNTL_SERIALIZED_ACCEPT)
static struct flock lock_it;
static struct flock unlock_it;
static int fcntl_fd=-1;
/*
* Initialize mutex lock.
* Must be safe to call this on a restart.
*/
void
accept_mutex_init(void)
{
lock_it.l_whence = SEEK_SET; /* from current point */
lock_it.l_start = 0; /* -"- */
lock_it.l_len = 0; /* until end of file */
lock_it.l_type = F_WRLCK; /* set exclusive/write lock */
lock_it.l_pid = 0; /* pid not actually interesting */
unlock_it.l_whence = SEEK_SET; /* from current point */
unlock_it.l_start = 0; /* -"- */
unlock_it.l_len = 0; /* until end of file */
unlock_it.l_type = F_UNLCK; /* set exclusive/write lock */
unlock_it.l_pid = 0; /* pid not actually interesting */
fcntl_fd = open("test-lock-thing", O_CREAT | O_WRONLY | O_EXCL, 0644);
if (fcntl_fd == -1)
{
perror ("open");
fprintf (stderr, "Cannot open lock file: %s\n", "test-lock-thing");
exit (1);
}
unlink("test-lock-thing");
}
void accept_mutex_on(void)
{
int ret;
while ((ret = fcntl(fcntl_fd, F_SETLKW, &lock_it)) < 0 && errno == EINTR)
continue;
if (ret < 0) {
perror ("fcntl lock_it");
exit(1);
}
}
void accept_mutex_off(void)
{
if (fcntl (fcntl_fd, F_SETLKW, &unlock_it) < 0)
{
perror ("fcntl unlock_it");
exit(1);
}
}
#elif defined(USE_FLOCK_SERIALIZED_ACCEPT)
#include <sys/file.h>
static int flock_fd=-1;
/*
* Initialize mutex lock.
* Must be safe to call this on a restart.
*/
void
accept_mutex_init(void)
{
flock_fd = open("test-lock-thing", O_CREAT | O_WRONLY | O_EXCL, 0644);
if (flock_fd == -1)
{
perror ("open");
fprintf (stderr, "Cannot open lock file: %s\n", "test-lock-thing");
exit (1);
}
unlink("test-lock-thing");
}
void accept_mutex_on(void)
{
int ret;
while ((ret = flock(flock_fd, LOCK_EX)) < 0 && errno == EINTR)
continue;
if (ret < 0) {
perror ("flock(LOCK_EX)");
exit(1);
}
}
void accept_mutex_off(void)
{
if (flock (flock_fd, LOCK_UN) < 0)
{
perror ("flock(LOCK_UN)");
exit(1);
}
}
#elif defined (USE_SYSVSEM_SERIALIZED_ACCEPT)
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
static int sem_id = -1;
void accept_mutex_init(void)
{
union semun {
int val;
struct semid_ds *buf;
ushort *array;
};
union semun ick;
sem_id = semget(999, 1, IPC_CREAT | 0666);
if (sem_id < 0) {
perror ("semget");
exit (1);
}
ick.val = 1;
if (semctl(sem_id, 0, SETVAL, ick) < 0) {
perror ("semctl");
exit(1);
}
}
void accept_mutex_on()
{
struct sembuf op;
op.sem_num = 0;
op.sem_op = -1;
op.sem_flg = SEM_UNDO;
if (semop(sem_id, &op, 1) < 0) {
perror ("accept_mutex_on");
exit (1);
}
}
void accept_mutex_off()
{
struct sembuf op;
op.sem_num = 0;
op.sem_op = 1;
op.sem_flg = SEM_UNDO;
if (semop(sem_id, &op, 1) < 0) {
perror ("accept_mutex_off");
exit (1);
}
}
#elif defined (USE_PTHREAD_SERIALIZED_ACCEPT)
#include <pthread.h>
static pthread_mutex_t *mutex;
static sigset_t accept_block_mask;
static sigset_t accept_previous_mask;
void accept_mutex_init(void)
{
pthread_mutexattr_t mattr;
int fd;
fd = open ("/dev/zero", O_RDWR);
if (fd == -1) {
perror ("open(/dev/zero)");
exit (1);
}
mutex = (pthread_mutex_t *)mmap ((caddr_t)0, sizeof (*mutex),
PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (mutex == (void *)(caddr_t)-1) {
perror ("mmap");
exit (1);
}
close (fd);
if (pthread_mutexattr_init(&mattr)) {
perror ("pthread_mutexattr_init");
exit (1);
}
if (pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED)) {
perror ("pthread_mutexattr_setpshared");
exit (1);
}
if (pthread_mutex_init(mutex, &mattr)) {
perror ("pthread_mutex_init");
exit (1);
}
sigfillset(&accept_block_mask);
sigdelset(&accept_block_mask, SIGHUP);
sigdelset(&accept_block_mask, SIGTERM);
sigdelset(&accept_block_mask, SIGUSR1);
}
void accept_mutex_on()
{
if (sigprocmask(SIG_BLOCK, &accept_block_mask, &accept_previous_mask)) {
perror("sigprocmask(SIG_BLOCK)");
exit (1);
}
if (pthread_mutex_lock (mutex)) {
perror ("pthread_mutex_lock");
exit (1);
}
}
void accept_mutex_off()
{
if (pthread_mutex_unlock (mutex)) {
perror ("pthread_mutex_unlock");
exit (1);
}
if (sigprocmask(SIG_SETMASK, &accept_previous_mask, NULL)) {
perror("sigprocmask(SIG_SETMASK)");
exit (1);
}
}
#elif defined (USE_USLOCK_SERIALIZED_ACCEPT)
#include <ulocks.h>
static usptr_t *us = NULL;
static ulock_t uslock = NULL;
void accept_mutex_init(void)
{
ptrdiff_t old;
/* default is 8 */
#define CONF_INITUSERS_MAX 15
if ((old = usconfig(CONF_INITUSERS, CONF_INITUSERS_MAX)) == -1) {
perror("usconfig");
exit(-1);
}
if ((old = usconfig(CONF_LOCKTYPE, US_NODEBUG)) == -1) {
perror("usconfig");
exit(-1);
}
if ((old = usconfig(CONF_ARENATYPE, US_SHAREDONLY)) == -1) {
perror("usconfig");
exit(-1);
}
if ((us = usinit("/dev/zero")) == NULL) {
perror("usinit");
exit(-1);
}
if ((uslock = usnewlock(us)) == NULL) {
perror("usnewlock");
exit(-1);
}
}
void accept_mutex_on()
{
switch(ussetlock(uslock)) {
case 1:
/* got lock */
break;
case 0:
fprintf(stderr, "didn't get lock\n");
exit(-1);
case -1:
perror("ussetlock");
exit(-1);
}
}
void accept_mutex_off()
{
if (usunsetlock(uslock) == -1) {
perror("usunsetlock");
exit(-1);
}
}
#endif
void main (int argc, char **argv)
{
int num_iter;
int num_child;
int i;
struct timeval first;
struct timeval last;
long ms;
int pid;
unsigned long *shared_counter;
if (argc != 3) {
fprintf (stderr, "Usage: time-sem num-child num-iter\n");
exit (1);
}
num_child = atoi (argv[1]);
num_iter = atoi (argv[2]);
/* allocate shared memory for the shared_counter */
i = open ("/dev/zero", O_RDWR);
if (i == -1) {
perror ("open");
exit (1);
}
shared_counter = (unsigned long *)mmap ((caddr_t)0,
sizeof (*shared_counter),
PROT_READ|PROT_WRITE, MAP_SHARED, i, 0);
if (shared_counter == (void *)(caddr_t)-1) {
perror ("mmap");
exit (1);
}
close (i);
/* initialize counter to 0 */
*shared_counter = 0;
accept_mutex_init ();
/* parent grabs mutex until done spawning children */
accept_mutex_on ();
for (i = 0; i < num_child; ++i) {
pid = fork();
if (pid == 0) {
/* child, do our thing */
for (i = 0; i < num_iter; ++i) {
accept_mutex_on ();
++*shared_counter;
accept_mutex_off ();
}
exit (0);
} else if (pid == -1) {
perror ("fork");
exit (1);
}
}
/* a quick test to see that nothing is screwed up */
if (*shared_counter != 0) {
puts ("WTF! shared_counter != 0 before the children have been started!");
exit (1);
}
gettimeofday (&first, NULL);
/* launch children into action */
accept_mutex_off ();
for (i = 0; i < num_child; ++i) {
if (wait(NULL) == -1) {
perror ("wait");
}
}
gettimeofday (&last, NULL);
if (*shared_counter != num_child * num_iter) {
puts ("WTF! shared_counter != num_child * num_iter!");
}
last.tv_sec -= first.tv_sec;
ms = last.tv_usec - first.tv_usec;
if (ms < 0) {
--last.tv_sec;
ms += 1000000;
}
last.tv_usec = ms;
printf ("%8lu.%06lu\n", last.tv_sec, last.tv_usec);
}