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/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
time-sem.c has the basics of the semaphores we use in http_main.c. It's
intended for timing differences between various methods on an
architecture. In practice we've found many things affect which semaphore
to be used:
- NFS filesystems absolutely suck for fcntl() and flock()
- uslock absolutely sucks on single-processor IRIX boxes, but
absolutely rocks on multi-processor boxes. The converse
is true for fcntl. sysvsem seems a moderate balance.
- Under Solaris you can't have too many processes use SEM_UNDO, there
might be a tuneable somewhere that increases the limit from 29.
We're not sure what the tunable is, so there's a define
NO_SEM_UNDO which can be used to simulate us trapping/blocking
signals to be able to properly release the semaphore on a clean
child death. You'll also need to define NEED_UNION_SEMUN
under solaris.
You'll need to define USE_SHMGET_SCOREBOARD if anonymous shared mmap()
doesn't work on your system (i.e. linux).
argv[1] is the #children, argv[2] is the #iterations per child
You should run each over many different #children inputs, and choose
#iter such that the program runs for at least a second or so... or even
longer depending on your patience.
compile with:
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-SYSVSEM -Wall -O time-sem.c -DUSE_SYSVSEM_SERIALIZED_ACCEPT
gcc -o time-SYSVSEM2 -Wall -O time-sem.c -DUSE_SYSVSEM_SERIALIZED_ACCEPT -DNO_SEM_UNDO
gcc -o time-PTHREAD -Wall -O time-sem.c -DUSE_PTHREAD_SERIALIZED_ACCEPT -lpthread
gcc -o time-USLOCK -Wall -O time-sem.c -DUSE_USLOCK_SERIALIZED_ACCEPT
not all versions work on all systems.
*/
#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;
#define accept_mutex_child_init()
#define accept_mutex_cleanup()
/*
* 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 */
printf("opening test-lock-thing in current directory\n");
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;
#define FNAME "test-lock-thing"
/*
* Initialize mutex lock.
* Must be safe to call this on a restart.
*/
void accept_mutex_init(void)
{
printf("opening " FNAME " in current directory\n");
flock_fd = open(FNAME, 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);
}
}
void accept_mutex_child_init(void)
{
flock_fd = open(FNAME, O_WRONLY, 0600);
if (flock_fd == -1) {
perror("open");
exit(1);
}
}
void accept_mutex_cleanup(void)
{
unlink(FNAME);
}
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;
#ifdef NO_SEM_UNDO
static sigset_t accept_block_mask;
static sigset_t accept_previous_mask;
#endif
#define accept_mutex_child_init()
#define accept_mutex_cleanup()
void accept_mutex_init(void)
{
#ifdef NEED_UNION_SEMUN
/* believe it or not, you need to define this under solaris */
union semun {
int val;
struct semid_ds *buf;
ushort *array;
};
#endif
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);
}
#ifdef NO_SEM_UNDO
sigfillset(&accept_block_mask);
sigdelset(&accept_block_mask, SIGHUP);
sigdelset(&accept_block_mask, SIGTERM);
sigdelset(&accept_block_mask, SIGUSR1);
#endif
}
void accept_mutex_on()
{
struct sembuf op;
#ifdef NO_SEM_UNDO
if (sigprocmask(SIG_BLOCK, &accept_block_mask, &accept_previous_mask)) {
perror("sigprocmask(SIG_BLOCK)");
exit (1);
}
op.sem_flg = 0;
#else
op.sem_flg = SEM_UNDO;
#endif
op.sem_num = 0;
op.sem_op = -1;
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;
#ifdef NO_SEM_UNDO
op.sem_flg = 0;
#else
op.sem_flg = SEM_UNDO;
#endif
if (semop(sem_id, &op, 1) < 0) {
perror ("accept_mutex_off");
exit (1);
}
#ifdef NO_SEM_UNDO
if (sigprocmask(SIG_SETMASK, &accept_previous_mask, NULL)) {
perror("sigprocmask(SIG_SETMASK)");
exit (1);
}
#endif
}
#elif defined (USE_PTHREAD_SERIALIZED_ACCEPT)
/* note: pthread mutexes aren't released on child death, hence the
* signal goop ... in a real implementation we'd do special things
* during hup, term, usr1.
*/
#include <pthread.h>
static pthread_mutex_t *mutex;
static sigset_t accept_block_mask;
static sigset_t accept_previous_mask;
#define accept_mutex_child_init()
#define accept_mutex_cleanup()
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;
#define accept_mutex_child_init()
#define accept_mutex_cleanup()
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
#ifndef USE_SHMGET_SCOREBOARD
static void *get_shared_mem(apr_size_t size)
{
void *result;
/* allocate shared memory for the shared_counter */
result = (unsigned long *)mmap ((caddr_t)0, size,
PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED, -1, 0);
if (result == (void *)(caddr_t)-1) {
perror ("mmap");
exit (1);
}
return result;
}
#else
#include <sys/types.h>
#include <sys/ipc.h>
#ifdef HAVE_SYS_MUTEX_H
#include <sys/mutex.h>
#endif
#include <sys/shm.h>
static void *get_shared_mem(apr_size_t size)
{
key_t shmkey = IPC_PRIVATE;
int shmid = -1;
void *result;
#ifdef MOVEBREAK
char *obrk;
#endif
if ((shmid = shmget(shmkey, size, IPC_CREAT | SHM_R | SHM_W)) == -1) {
perror("shmget");
exit(1);
}
#ifdef MOVEBREAK
/*
* Some SysV systems place the shared segment WAY too close
* to the dynamic memory break point (sbrk(0)). This severely
* limits the use of malloc/sbrk in the program since sbrk will
* refuse to move past that point.
*
* To get around this, we move the break point "way up there",
* attach the segment and then move break back down. Ugly
*/
if ((obrk = sbrk(MOVEBREAK)) == (char *) -1) {
perror("sbrk");
}
#endif
#define BADSHMAT ((void *)(-1))
if ((result = shmat(shmid, 0, 0)) == BADSHMAT) {
perror("shmat");
}
/*
* We must avoid leaving segments in the kernel's
* (small) tables.
*/
if (shmctl(shmid, IPC_RMID, NULL) != 0) {
perror("shmctl(IPC_RMID)");
}
if (result == BADSHMAT) /* now bailout */
exit(1);
#ifdef MOVEBREAK
if (obrk == (char *) -1)
return; /* nothing else to do */
if (sbrk(-(MOVEBREAK)) == (char *) -1) {
perror("sbrk 2");
}
#endif
return result;
}
#endif
#ifdef _POSIX_PRIORITY_SCHEDULING
/* don't ask */
#define _P __P
#include <sched.h>
#define YIELD sched_yield()
#else
#define YIELD do { struct timeval zero; zero.tv_sec = zero.tv_usec = 0; select(0,0,0,0,&zero); } while(0)
#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 */
shared_counter = get_shared_mem(sizeof(*shared_counter));
/* 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 */
accept_mutex_child_init();
for (i = 0; i < num_iter; ++i) {
unsigned long tmp;
accept_mutex_on ();
tmp = *shared_counter;
YIELD;
*shared_counter = tmp + 1;
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) {
printf ("WTF! shared_counter != num_child * num_iter!\n"
"shared_counter = %lu\nnum_child = %d\nnum_iter=%d\n",
*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);
accept_mutex_cleanup();
exit(0);
}
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