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lasp/lasp/c/lasp_mq.c

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// lasp_mq.c
//
// Author: J.A. de Jong -ASCEE
//
// Description: Message queue implementation using a linked
// list. Using mutexes and condition variables to sync access between
// different threads.
//////////////////////////////////////////////////////////////////////
#define TRACERPLUS (-6)
#include "lasp_types.h"
#include "lasp_tracer.h"
#include "lasp_assert.h"
#include "lasp_alloc.h"
#include "lasp_mq.h"
#include <pthread.h>
/* #ifdef linux */
#define _GNU_SOURCE
#include <sys/types.h>
#include <unistd.h>
#ifndef MS_WIN64
#include <sys/syscall.h>
#endif
/* #endif */
typedef struct {
void* job_ptr;
bool running;
bool ready;
} Job;
typedef struct JobQueue_s {
#ifdef LASP_PARALLEL
pthread_mutex_t mutex;
pthread_cond_t cv_plus; /**< Condition variable for the
* "workers". */
pthread_cond_t cv_minus; /**< Condition variable for the
* main thread. */
#endif
Job* jobs; /**< Pointer to job vector */
us max_jobs; /**< Stores the maximum number of
* items */
} JobQueue;
static us count_jobs(JobQueue* jq) {
fsTRACE(15);
us njobs = 0;
for(us i=0;i<jq->max_jobs;i++){
if(jq->jobs[i].ready)
njobs++;
}
return njobs;
}
static Job* get_ready_job(JobQueue* jq) {
fsTRACE(15);
Job* j = jq->jobs;
for(us i=0;i<jq->max_jobs;i++){
if(j->ready && !j->running)
return j;
j++;
}
return NULL;
}
void print_job_queue(JobQueue* jq) {
fsTRACE(15);
for(us i=0;i<jq->max_jobs;i++) {
printf("Job %zu", i);
if(jq->jobs[i].ready)
printf(" available");
if(jq->jobs[i].running)
printf(" running");
printf(" - ptr %zu\n", (us) jq->jobs[i].job_ptr);
}
feTRACE(15);
}
#ifdef LASP_PARALLEL
#define LOCK_MUTEX \
/* Lock the mutex to let the threads wait initially */ \
int rv = pthread_mutex_lock(&jq->mutex); \
if(rv !=0) { \
WARN("Mutex lock failed"); \
}
#define UNLOCK_MUTEX \
rv = pthread_mutex_unlock(&jq->mutex); \
if(rv !=0) { \
WARN("Mutex unlock failed"); \
}
#else
#define LOCK_MUTEX
#define UNLOCK_MUTEX
#endif // LASP_PARALLEL
JobQueue* JobQueue_alloc(const us max_jobs) {
TRACE(15,"JobQueue_alloc");
if(max_jobs > LASP_MAX_NUM_CHANNELS) {
WARN("Max jobs restricted to LASP_MAX_NUM_CHANNELS");
return NULL;
}
JobQueue* jq = a_malloc(sizeof(JobQueue));
if(!jq) {
WARN("Allocation of JobQueue failed");
return NULL;
}
jq->max_jobs = max_jobs;
jq->jobs = a_malloc(max_jobs*sizeof(Job));
if(!jq->jobs) {
WARN("Allocation of JobQueue jobs failed");
return NULL;
}
Job* j = jq->jobs;
for(us jindex=0;jindex<max_jobs;jindex++) {
j->job_ptr = NULL;
j->ready = false;
j->running = false;
j++;
}
#ifdef LASP_PARALLEL
/* Initialize thread mutex */
int rv = pthread_mutex_init(&jq->mutex,NULL);
if(rv !=0) {
WARN("Mutex initialization failed");
return NULL;
}
rv = pthread_cond_init(&jq->cv_plus,NULL);
if(rv !=0) {
WARN("Condition variable initialization failed");
return NULL;
}
rv = pthread_cond_init(&jq->cv_minus,NULL);
if(rv !=0) {
WARN("Condition variable initialization failed");
return NULL;
}
#endif // LASP_PARALLEL
/* print_job_queue(jq); */
return jq;
}
void JobQueue_free(JobQueue* jq) {
TRACE(15,"JobQueue_free");
dbgassert(jq,NULLPTRDEREF "jq in JobQueue_free");
int rv;
if(count_jobs(jq) != 0) {
WARN("Job queue not empty!");
}
a_free(jq->jobs);
#ifdef LASP_PARALLEL
/* Destroy the mutexes and condition variables */
rv = pthread_mutex_destroy(&jq->mutex);
if(rv != 0){
WARN("Mutex destroy failed. Do not know what to do.");
}
rv = pthread_cond_destroy(&jq->cv_plus);
if(rv != 0){
WARN("Condition variable destruction failed. "
"Do not know what to do.");
}
rv = pthread_cond_destroy(&jq->cv_minus);
if(rv != 0){
WARN("Condition variable destruction failed. "
"Do not know what to do.");
}
#endif // LASP_PARALLEL
}
int JobQueue_push(JobQueue* jq,void* job_ptr) {
TRACE(15,"JobQueue_push");
dbgassert(jq,NULLPTRDEREF "jq in JobQueue_push");
/* print_job_queue(jq); */
/* uVARTRACE(15,(us) job_ptr); */
LOCK_MUTEX;
us max_jobs = jq->max_jobs;
#ifdef LASP_PARALLEL
/* Check if queue is full */
while(count_jobs(jq) == max_jobs) {
WARN("Queue full. Wait until some jobs are done.");
rv = pthread_cond_wait(&jq->cv_minus,&jq->mutex);
if(rv !=0) {
WARN("Condition variable wait failed");
}
}
#else
/* If job queue is full, not in parallel, we just fail to add something
* without waiting*/
if(count_jobs(jq) == max_jobs) {
return LASP_FAILURE;
}
#endif // LASP_PARALLEL
dbgassert(count_jobs(jq) != max_jobs,
"Queue cannot be full!");
/* Queue is not full try to find a place, fill it */
Job* j = jq->jobs;
us i;
for(i=0;i<max_jobs;i++) {
if(j->ready == false ) {
dbgassert(j->job_ptr==NULL,"Job ptr should be 0");
dbgassert(j->ready==false,"Job cannot be assigned");
break;
}
j++;
}
dbgassert(i!=jq->max_jobs,"Should have found a job!");
j->job_ptr = job_ptr;
j->ready = true;
#ifdef LASP_PARALLEL
/* Notify worker threads that a new job has arrived */
if(count_jobs(jq) == max_jobs) {
/* Notify ALL threads. Action required! */
rv = pthread_cond_broadcast(&jq->cv_plus);
if(rv !=0) {
WARN("Condition variable broadcast failed");
}
} else {
/* Notify some thread that there has been some change to
* the Queue */
rv = pthread_cond_signal(&jq->cv_plus);
if(rv !=0) {
WARN("Condition variable signal failed");
}
}
#endif // LASP_PARALLEL
/* print_job_queue(jq); */
UNLOCK_MUTEX;
return LASP_SUCCESS;
}
void* JobQueue_assign(JobQueue* jq) {
TRACE(15,"JobQueue_assign");
LOCK_MUTEX;
Job* j;
#ifdef LASP_PARALLEL
/* Wait until a job is available */
while ((j=get_ready_job(jq))==NULL) {
TRACE(15,"JobQueue_assign: no ready job");
pthread_cond_wait(&jq->cv_plus,&jq->mutex);
}
#else
if(count_jobs(jq) == 0) { return NULL; }
else { j = get_ready_job(jq); }
#endif // LASP_PARALLEL
TRACE(16,"JobQueue_assign: found ready job. Assigned to:");
#ifdef LASP_DEBUG
#ifdef LASP_PARALLEL
pthread_t thisthread = pthread_self();
iVARTRACE(16,thisthread);
#endif
#endif
/* print_job_queue(jq); */
/* Find a job from the queue, assign it and return it */
j->running = true;
#ifdef LASP_PARALLEL
if(count_jobs(jq) > 1) {
/* Signal different thread that there is more work to do */
rv = pthread_cond_signal(&jq->cv_plus);
if(rv !=0) {
WARN("Condition variable broadcast failed");
}
}
#endif
UNLOCK_MUTEX;
TRACE(15,"End JobQueue_assign");
return j->job_ptr;
}
void JobQueue_done(JobQueue* jq,void* job_ptr) {
TRACE(15,"JobQueue_done");
dbgassert(jq,NULLPTRDEREF "jq in JobQueue_done");
LOCK_MUTEX;
/* print_job_queue(jq); */
/* Find the job from the queue, belonging to the job_ptr */
Job* j=jq->jobs;
us i;
for(i=0;i<jq->max_jobs;i++) {
iVARTRACE(10,i);
if(j->ready && j->running && j->job_ptr == job_ptr) {
TRACE(15,"Found the job that has been done:");
j->ready = false;
j->job_ptr = NULL;
j->running = false;
break;
}
j++;
}
/* print_job_queue(jq); */
#ifdef LASP_PARALLEL
/* Job done, broadcast this */
rv = pthread_cond_signal(&jq->cv_minus);
if(rv !=0) {
WARN("Condition variable broadcast failed");
}
#endif
UNLOCK_MUTEX;
}
#ifdef LASP_PARALLEL
void JobQueue_wait_alldone(JobQueue* jq) {
TRACE(15,"JobQueue_wait_alldone");
dbgassert(jq,NULLPTRDEREF "jq in JobQueue_wait_alldone");
LOCK_MUTEX;
/* Wait until number of jobs is 0 */
while (count_jobs(jq)!=0) {
if(rv !=0) {
WARN("Condition variable broadcast failed");
}
pthread_cond_wait(&jq->cv_minus,&jq->mutex);
}
UNLOCK_MUTEX;
}
#endif
//////////////////////////////////////////////////////////////////////
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