this is the coding for the 'default' apr_atomic
it uses a >7< mutex locks (it picks one based on a hash of the memory pointer) to provide the locking. this of course can be increased to
reduce contention.
If no one objects I'll add this (and unix support files) and we can figure out a method of getting OS/CPU specific stuff in.
/* ==================================================================== * The Apache Software License, Version 1.1 * * Copyright (c) 2000-2001 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, * if any, must include the following acknowledgment: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowledgment may appear in the software itself, * if and wherever such third-party acknowledgments normally appear. * * 4. The names "Apache" and "Apache Software Foundation" must * not be used to endorse or promote products derived from this * software without prior written permission. For written * permission, please contact [EMAIL PROTECTED] * * 5. Products derived from this software may not be called "Apache", * nor may "Apache" appear in their name, without prior written * permission of the Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. */
#include "apr_thread_proc.h"
#include "apr_lock.h"
#include "apr_errno.h"
#include "apr_general.h"
#include "apr_atomic.h"
#include "errno.h"
#include <stdio.h>
#include <stdlib.h>
#include "apr_time.h"
#if APR_HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifndef WIN32
#include <pthread.h>
#endif
#if !APR_HAS_THREADS
int main(void)
{
fprintf(stderr,
"This program won't work on this platform because there is no "
"support for threads.\n");
return 0;
}
#else /* !APR_HAS_THREADS */
void * APR_THREAD_FUNC thread_func_traditional(apr_thread_t *thd, void *data);
void * APR_THREAD_FUNC thread_func_atomic(apr_thread_t *thd, void *data);
void * APR_THREAD_FUNC thread_func_none(apr_thread_t *thd, void *data);
apr_lock_t *thread_lock;
apr_pool_t *context;
apr_thread_once_t *control = NULL;
volatile long x = 0; /* traditional locks */
volatile long y = 0; /* atomic locks */
volatile long z = 0; /* no locks */
int value = 0;
apr_status_t exit_ret_val = 123; /* just some made up number to check on later
*/
#define NUM_THREADS 10
#define NUM_ITERATIONS 20000
static void init_func(void)
{
value++;
}
void * APR_THREAD_FUNC thread_func_traditional(apr_thread_t *thd, void *data)
{
int i;
apr_thread_once(control, init_func);
for (i = 0; i < NUM_ITERATIONS; i++) {
apr_lock_acquire(thread_lock);
x++;
apr_lock_release(thread_lock);
}
apr_thread_exit(thd, exit_ret_val);
return NULL;
}
void * APR_THREAD_FUNC thread_func_atomic(apr_thread_t *thd, void *data)
{
int i;
apr_thread_once(control, init_func);
for (i = 0; i < NUM_ITERATIONS ; i++) {
apr_atomic_inc( &y );
}
apr_thread_exit(thd, exit_ret_val);
return NULL;
}
void * APR_THREAD_FUNC thread_func_none(apr_thread_t *thd, void *data)
{
int i;
apr_thread_once(control, init_func);
for (i = 0; i < NUM_ITERATIONS ; i++) {
z++;
}
apr_thread_exit(thd, exit_ret_val);
return NULL;
}
int main(void)
{
apr_thread_t *t1[NUM_THREADS];
apr_thread_t *t2[NUM_THREADS];
apr_thread_t *t3[NUM_THREADS];
apr_status_t r1[NUM_THREADS];
apr_status_t r2[NUM_THREADS];
apr_status_t r3[NUM_THREADS];
apr_status_t s1[NUM_THREADS];
apr_status_t s2[NUM_THREADS];
apr_status_t s3[NUM_THREADS];
apr_status_t rv;
int i;
apr_initialize();
printf("APR Simple Thread Test\n======================\n\n");
#ifndef WIN32
pthread_setconcurrency(8);
#endif
printf("%-60s", "Initializing the context");
if (apr_pool_create(&context, NULL) != APR_SUCCESS) {
fflush(stdout);
fprintf(stderr, "Failed.\nCould not initialize\n");
exit(-1);
}
printf("OK\n");
apr_thread_once_init(&control, context);
printf("%-60s", "Initializing the lock");
rv = apr_lock_create(&thread_lock, APR_MUTEX, APR_INTRAPROCESS,
APR_LOCK_DEFAULT, "lock.file", context);
if (rv != APR_SUCCESS) {
fflush(stdout);
fprintf(stderr, "Failed\nCould not create lock\n");
exit(-1);
}
rv = apr_atomic_init( context);
printf("OK\n");
printf("%-60s", "Starting all the threads");
for (i=0;i<NUM_THREADS;i++) {
r1[i] = apr_thread_create(&t1[i], NULL, thread_func_traditional, NULL,
context);
r2[i] = apr_thread_create(&t2[i], NULL, thread_func_atomic, NULL,
context);
r3[i] = apr_thread_create(&t3[i], NULL, thread_func_none, NULL,
context);
if (r1[i] != APR_SUCCESS || r2[i] != APR_SUCCESS ||
r3[i] != APR_SUCCESS ) {
fflush(stdout);
fprintf(stderr, "Failed\nError starting thread in group %d\n",i);
exit(-1);
}
}
printf("OK\n");
printf("%-60s", "Waiting for threads to exit");
fflush(stdout);
for (i=0;i<NUM_THREADS;i++) {
apr_thread_join(&s1[i], t1[i]);
apr_thread_join(&s2[i], t2[i]);
apr_thread_join(&s3[i], t3[i]);
if (s1[i] != exit_ret_val || s2[i] != exit_ret_val ||
s3[i] != exit_ret_val ) {
fprintf(stderr,
"Invalid return value\nGot %d/%d/%d, but expected %d
for all \n",
s1[i], s2[i], s3[i], exit_ret_val);
}
}
printf("OK\n");
printf("%-60s", "Checking if locks worked");
if (x != NUM_THREADS*NUM_ITERATIONS) {
fflush(stdout);
fprintf(stderr, "No!\nThe locks didn't work???? x = %ld instead of
%ld\n", x,NUM_THREADS*NUM_ITERATIONS);
}
else
printf("OK\n");
printf("%-60s", "Checking if atomic worked");
if (apr_atomic_read(&y) != NUM_THREADS*NUM_ITERATIONS) {
fflush(stdout);
fprintf(stderr, "No!\nThe atomics didn't work???? y = %ld instead of
%ld\n", y,NUM_THREADS*NUM_ITERATIONS);
}
else
printf("OK\n");
printf("%-60s", "Checking if nolock worked");
if ( z != NUM_THREADS*NUM_ITERATIONS) {
fflush(stdout);
fprintf(stderr, "no suprise\nThe no-locks didn't work???? z = %ld
instead of %ld\n", z, NUM_THREADS*NUM_ITERATIONS);
}
else
printf("OK\n");
printf("%-60s", "Checking if apr_thread_once worked");
if (value != 1) {
fflush(stdout);
fprintf(stderr, "Failed!\napr_thread_once must not have worked, "
"value is %d instead of 1\n", value);
exit(-1);
}
printf("OK\n");
return 0;
}
#endif /* !APR_HAS_THREADS */
/* ==================================================================== * The Apache Software License, Version 1.1 * * Copyright (c) 2000-2001 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * 3. The end-user documentation included with the redistribution, * if any, must include the following acknowledgment: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowledgment may appear in the software itself, * if and wherever such third-party acknowledgments normally appear. * * 4. The names "Apache" and "Apache Software Foundation" must * not be used to endorse or promote products derived from this * software without prior written permission. For written * permission, please contact [EMAIL PROTECTED] * * 5. Products derived from this software may not be called "Apache", * nor may "Apache" appear in their name, without prior written * permission of the Apache Software Foundation. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * Portions of this software are based upon public domain software * originally written at the National Center for Supercomputing Applications, * University of Illinois, Urbana-Champaign. */ #ifndef APR_ATOMIC_H #define APR_ATOMIC_H #ifdef __cplusplus extern "C" { #endif #ifdef WIN32 #define apr_atomic_add(mem, val) InterlockedExchangeAdd(mem,val) #define apr_atomic_dec(mem) InterlockedDecrement(mem) #define apr_atomic_inc(mem) InterlockedIncrement(mem) #define apr_atomic_set(mem, val) InterlockedExchange(mem, val) #define apr_atomic_read(mem) *mem #define apr_atomic_cas(mem,with,cmp) InterlockedCompareExchange(mem,with,cmp) #define apr_atomic_init(pool) APR_SUCCESS #else #define apr_atomic_read(p) *p apr_status_t apr_atomic_init(apr_pool_t *p); long apr_atomic_set(volatile long*mem, long val); long apr_atomic_add(volatile long*mem, long val); long apr_atomic_inc( volatile long *mem); long apr_atomic_dec(volatile long *mem); long apr_atomic_cas(volatile long *mem,long with,long cmp); #endif #ifdef __cplusplus } #endif #endif /* !APR_ATOMIC_H */
#include "apr.h"
#include "apr_lock.h"
#include "apr_thread_mutex.h"
#include "apr_atomic.h"
#ifdef WIN32
/* win32 implementation is all macros */
#else
#define NUM_ATOMIC_HASH 7
/* shift by 2 to get rid of alignment issues */
#define ATOMIC_HASH(x) (int)(((long)x>>2)%NUM_ATOMIC_HASH)
static apr_thread_mutex_t **hash_mutex;
apr_status_t apr_atomic_init(apr_pool_t *p )
{
int i;
apr_status_t rv;
hash_mutex =apr_palloc(p,sizeof(apr_thread_mutex_t*) * NUM_ATOMIC_HASH);
for (i=0;i<NUM_ATOMIC_HASH;i++) {
rv = apr_thread_mutex_create(&(hash_mutex[i]),
APR_THREAD_MUTEX_DEFAULT, p);
if (rv != APR_SUCCESS)
return rv;
}
return APR_SUCCESS;
}
long apr_atomic_add(volatile long*mem, long val)
{
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
long prev;
if (apr_thread_mutex_lock(lock) == APR_SUCCESS) {
prev = *mem;
*mem += val;
apr_thread_mutex_unlock(lock);
return prev;
}
return *mem;
}
long apr_atomic_set(volatile long*mem, long val)
{
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
long prev;
if (apr_thread_mutex_lock(lock) == APR_SUCCESS) {
prev = *mem;
*mem = val;
apr_thread_mutex_unlock(lock);
return prev;
}
return *mem;
}
long apr_atomic_inc( volatile long *mem)
{
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
long prev;
if (apr_thread_mutex_lock(lock) == APR_SUCCESS) {
prev = *mem;
(*mem)++;
apr_thread_mutex_unlock(lock);
return prev;
}
return *mem;
}
long apr_atomic_dec(volatile long *mem)
{
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
long prev;
if (apr_thread_mutex_lock(lock) == APR_SUCCESS) {
prev = *mem;
(*mem)--;
apr_thread_mutex_unlock(lock);
return prev;
}
return *mem;
}
long apr_atomic_cas(volatile long *mem,long with,long cmp)
{
apr_thread_mutex_t *lock = hash_mutex[ATOMIC_HASH(mem)];
long prev;
if (apr_thread_mutex_lock(lock) == APR_SUCCESS) {
prev = *mem;
if ( *mem == cmp) {
*mem = with;
}
apr_thread_mutex_unlock(lock);
return prev;
}
return *mem;
}
#endif /* default implementation */
