util/u_queue: add an option to set the minimum thread priority

Reviewed-by: Nicolai Hähnle <[email protected]>

3 files changed, 24 insertions, 3 deletions

diff --git a/src/util/disk_cache.c b/src/util/disk_cache.c
index 138d7ec174f..b2229874e01 100644
--- a/src/util/disk_cache.c
+++ b/src/util/disk_cache.c
@@ -342,7 +342,7 @@ disk_cache_create(const char *gpu_name, const char *timestamp,
     * really care about getting things to disk quickly just that it's not
     * blocking other tasks.
     */
-   util_queue_init(&cache->cache_queue, "disk_cache", 32, 1);
+   util_queue_init(&cache->cache_queue, "disk_cache", 32, 1, 0);
 
    /* Create driver id keys */
    size_t ts_size = strlen(timestamp) + 1;
diff --git a/src/util/u_queue.c b/src/util/u_queue.c
index 01c3a96d5f3..94fe2202a2c 100644
--- a/src/util/u_queue.c
+++ b/src/util/u_queue.c
@@ -147,6 +147,21 @@ util_queue_thread_func(void *input)
       u_thread_setname(name);
    }
 
+   if (queue->flags & UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY) {
+#if defined(__linux__)
+      struct sched_param sched_param = {0};
+
+      /* The nice() function can only set a maximum of 19.
+       * SCHED_IDLE is the same as nice = 20.
+       *
+       * Note that Linux only allows decreasing the priority. The original
+       * priority can't be restored.
+       */
+      pthread_setschedparam(queue->threads[thread_index], SCHED_IDLE,
+                            &sched_param);
+#endif
+   }
+
    while (1) {
       struct util_queue_job job;
 
@@ -197,13 +212,15 @@ bool
 util_queue_init(struct util_queue *queue,
                 const char *name,
                 unsigned max_jobs,
-                unsigned num_threads)
+                unsigned num_threads,
+                unsigned flags)
 {
    unsigned i;
 
    memset(queue, 0, sizeof(*queue));
    queue->name = name;
    queue->num_threads = num_threads;
+   queue->flags = flags;
    queue->max_jobs = max_jobs;
 
    queue->jobs = (struct util_queue_job*)
diff --git a/src/util/u_queue.h b/src/util/u_queue.h
index 9876865c651..916802c96d1 100644
--- a/src/util/u_queue.h
+++ b/src/util/u_queue.h
@@ -42,6 +42,8 @@
 extern "C" {
 #endif
 
+#define UTIL_QUEUE_INIT_USE_MINIMUM_PRIORITY      (1 << 0)
+
 /* Job completion fence.
  * Put this into your job structure.
  */
@@ -69,6 +71,7 @@ struct util_queue {
    thrd_t *threads;
    int num_queued;
    unsigned num_threads;
+   unsigned flags;
    int kill_threads;
    int max_jobs;
    int write_idx, read_idx; /* ring buffer pointers */
@@ -81,7 +84,8 @@ struct util_queue {
 bool util_queue_init(struct util_queue *queue,
                      const char *name,
                      unsigned max_jobs,
-                     unsigned num_threads);
+                     unsigned num_threads,
+                     unsigned flags);
 void util_queue_destroy(struct util_queue *queue);
 void util_queue_fence_init(struct util_queue_fence *fence);
 void util_queue_fence_destroy(struct util_queue_fence *fence);