raster_threading: Added ParallelQueue system as helper

It will be used to push tessellated quads to render area.

src/rendering/tools/parallel.c

@@ -140,3 +140,198 @@ int parallelWorkPerform(ParallelWork* work, int workers)
     work->running = 0;
     return result;
 }
+
+
+#define QUEUE_SIZE 200
+
+typedef enum
+{
+    JOB_STATE_FREE,
+    JOB_STATE_PENDING,
+    JOB_STATE_PROCESSING,
+    JOB_STATE_TOCOLLECT
+} EnumJobState;
+
+typedef struct
+{
+    EnumJobState state;
+    int id;
+    FuncParallelJob process;
+    void* data;
+} ParallelJob;
+
+struct ParallelQueue
+{
+    int collect;
+    volatile int stopping;
+    Mutex* lock;
+
+    int workers_count;
+    Thread** workers;
+
+    ParallelJob* jobs;
+    int jobs_count;          /** Number of jobs in queue (all status except JOB_STATE_FREE) */
+    int jobs_index_free;     /** Index of next free position */
+    int jobs_index_collect;  /** Index of first job to collect */
+    int jobs_index_pending;  /** Index of first pending job to process */
+    int jobs_next_id;
+};
+
+static void* _queueThreadCallback(ParallelQueue* queue)
+{
+    ParallelJob* job;
+
+    while (!queue->stopping)
+    {
+        /* Try to take a job */
+        mutexAcquire(queue->lock);
+        job = queue->jobs + queue->jobs_index_pending;
+        if (job->state == JOB_STATE_PENDING)
+        {
+            if (queue->jobs_index_pending == QUEUE_SIZE - 1)
+            {
+                queue->jobs_index_pending = 0;
+            }
+            else
+            {
+                queue->jobs_index_pending++;
+            }
+            job->state = JOB_STATE_PROCESSING;
+        }
+        else
+        {
+            job = NULL;
+        }
+        mutexRelease(queue->lock);
+
+        if (job)
+        {
+            /* Process the job */
+            job->process(queue, job->id, job->data, 0);
+
+            mutexAcquire(queue->lock);
+            if (queue->collect)
+            {
+                job->state = JOB_STATE_TOCOLLECT;
+                /* TODO jobs_index_collect ? */
+            }
+            else
+            {
+                job->state = JOB_STATE_FREE;
+            }
+            mutexRelease(queue->lock);
+        }
+
+        timeSleepMs(50);
+    }
+    return NULL;
+}
+
+ParallelQueue* parallelQueueCreate(int collect)
+{
+    int i;
+
+    assert(!collect); /* Not fully implemented yet ! */
+
+    ParallelQueue* queue = malloc(sizeof(ParallelQueue));
+
+    queue->collect = collect;
+    queue->stopping = 0;
+    queue->lock = mutexCreate();
+
+    queue->workers_count = systemGetCoreCount();
+    queue->workers = malloc(sizeof(Thread*) * queue->workers_count);
+    for (i = 0; i < queue->workers_count; i++)
+    {
+        queue->workers[i] = threadCreate((ThreadFunction)_queueThreadCallback, queue);
+    }
+
+    queue->jobs = malloc(sizeof(ParallelJob) * QUEUE_SIZE);
+    queue->jobs_count = 0;
+    queue->jobs_index_free = 0;
+    queue->jobs_index_collect = 0;
+    queue->jobs_index_pending = 0;
+    queue->jobs_next_id = 1;
+
+    return queue;
+}
+
+void parallelQueueDelete(ParallelQueue* queue)
+{
+    parallelQueueInterrupt(queue);
+
+    assert(!queue->collect || queue->jobs[queue->jobs_index_collect].state != JOB_STATE_TOCOLLECT);
+
+    mutexDestroy(queue->lock);
+    free(queue->jobs);
+    free(queue->workers);
+    free(queue);
+}
+
+void parallelQueueInterrupt(ParallelQueue* queue)
+{
+    int i;
+
+    if (!queue->stopping)
+    {
+        queue->stopping = 1;
+
+        for (i = 0; i < queue->workers_count; i++)
+        {
+            threadJoin(queue->workers[i]);
+        }
+    }
+}
+
+int parallelQueueAddJob(ParallelQueue* queue, FuncParallelJob func_process, void* data)
+{
+    if (queue->stopping)
+    {
+        return 0;
+    }
+
+    /* Wait for a free slot */
+    while (queue->jobs[queue->jobs_index_free].state != JOB_STATE_FREE)
+    {
+        timeSleepMs(50);
+        if (queue->stopping)
+        {
+            return 0;
+        }
+    }
+
+    /* Prepare the job */
+    ParallelJob job;
+    job.state = JOB_STATE_PENDING;
+    job.id = queue->jobs_next_id++;
+    job.process = func_process;
+    job.data = data;
+
+    /* Add the job to the queue */
+    mutexAcquire(queue->lock);
+    if (queue->stopping)
+    {
+        mutexRelease(queue->lock);
+        return 0;
+    }
+    queue->jobs[queue->jobs_index_free] = job;
+    if (queue->jobs_index_free == QUEUE_SIZE - 1)
+    {
+        queue->jobs_index_free = 0;
+    }
+    else
+    {
+        queue->jobs_index_free++;
+    }
+    queue->jobs_count++;
+    assert(queue->jobs_count <= QUEUE_SIZE);
+    mutexRelease(queue->lock);
+
+    return job.id;
+}
+
+int parallelQueueCollectJobs(FuncParallelJob func_collect)
+{
+    /* TODO */
+    return 0;
+}

src/rendering/tools/parallel.h

@@ -16,13 +16,86 @@ extern "C" {
 typedef struct ParallelWork ParallelWork;
 typedef int (*ParallelUnitFunction)(ParallelWork* work, int unit, void* data);
 
-/*void parallelInit();
-void parallelQuit();*/
-
+/**
+ * Create a parallel work handler.
+ *
+ * This will spawn an optimal number of threads to process a given number of work units.
+ * @param func The callback that will be called from threads to process one unit.
+ * @param units Number of units to handle.
+ * @param data Custom data that will be passed to the callback.
+ * @return The newly allocated handler.
+ */
 ParallelWork* parallelWorkCreate(ParallelUnitFunction func, int units, void* data);
+
+/**
+ * Delete a parallel work handler.
+ *
+ * The work must be terminated or fully interrupted before calling this.
+ * @param work The handler to free.
+ */
 void parallelWorkDelete(ParallelWork* work);
+
+/**
+ * Start working on the units.
+ *
+ * @param work The handler.
+ * @param workers Number of threads to spaws, -1 for an optimal number.
+ */
 int parallelWorkPerform(ParallelWork* work, int workers);
 
+
+
+typedef struct ParallelQueue ParallelQueue;
+typedef int (*FuncParallelJob)(ParallelQueue* queue, int job_id, void* data, int stopping);
+
+/**
+ * Create a parallel processing queue.
+ *
+ * This queue will use parallel workers to process jobs added to it.
+ * @param collect True to collect finished jobs and wait for a call to parallelQueueCollectJobs, False to discard finished jobs.
+ * @return The newly allocated queue.
+ */
+ParallelQueue* parallelQueueCreate(int collect);
+
+/**
+ * Delete a parallel queue.
+ *
+ * This will interrupt the queue.
+ * If the queue is in collect mode, you should call parallelQueueInterrupt, then parallelQueueCollectJobs, before calling this.
+ * @param queue The queue to free.
+ */
+void parallelQueueDelete(ParallelQueue* queue);
+
+/**
+ * Interrupt the queue processing.
+ *
+ * This will wait for running jobs to end, cancel pending jobs (still calling their callbacks with stopping=1) and
+ * refuse future jobs.
+ * @param queue The queue to interrupt.
+ */
+void parallelQueueInterrupt(ParallelQueue* queue);
+
+/**
+ * Add a job to the queue.
+ *
+ * Don't call this method concurrently from several threads.
+ * @param queue The queue.
+ * @param func_process The function that will be called for the job processing.
+ * @param data The data that will be passed to the callback.
+ * @return The job ID, 0 if the queue doesn't accept jobs.
+ */
+int parallelQueueAddJob(ParallelQueue* queue, FuncParallelJob func_process, void* data);
+
+/**
+ * Collect finished jobs.
+ *
+ * The callback func_collect will be called sequentially for each finished job, from the caller thread (not parallel threads).
+ * Don't call this method concurrently from several threads.
+ * @param func_collect The callback for collect.
+ * @return The number of collected jobs.
+ */
+int parallelQueueCollectJobs(FuncParallelJob func_collect);
+
 #ifdef __cplusplus
 }
 #endif