Add TX thread pool prototype

Author: Cuda-Chen

virtio-snd.c

@@ -20,8 +20,6 @@
 
 #define PRIV(x) ((virtio_snd_config_t *) x->priv)
 
-static int cnt = 0;
-
 enum {
     VSND_QUEUE_CTRL = 0,
     VSND_QUEUE_EVT = 1,
@@ -277,6 +275,8 @@ typedef struct {
 static vsnd_stream_sel_t v;
 
 static pthread_mutex_t virtio_snd_mutex = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t virtio_snd_foo_cond = PTHREAD_COND_INITIALIZER;
+static int ev_notify;
 
 /* Forward declaration */
 static void virtio_snd_cb(struct CNFADriver *dev,
@@ -801,6 +801,14 @@ static int virtio_snd_tx_desc_handler(virtio_snd_state_t *vsnd,
     return 0;
 }
 
+/* XXX: merely testing the effectiveness of TX thread pool */
+static int virtio_snd_foo_desc_handler(virtio_snd_state_t *vsnd,
+                                      const virtio_snd_queue_t *queue,
+                                      uint32_t desc_idx,
+                                      uint32_t *plen) {
+    return 0;
+}
+
 static void virtio_queue_notify_handler(
     virtio_snd_state_t *vsnd,
     int index,
@@ -873,6 +881,25 @@ static void virtio_queue_notify_handler(
     }
 }
 
+/* XXX: used for TX thread testing */
+static void *func(void *args) {
+    virtio_snd_state_t *vsnd = (virtio_snd_state_t *)args;
+    fprintf(stderr, "*** foo desc handler is called ***\n");
+    pthread_mutex_lock(&virtio_snd_mutex);
+    while(ev_notify <= 0) {
+        pthread_cond_wait(&virtio_snd_foo_cond, &virtio_snd_mutex);
+        fprintf(stderr, "wait for cond\n");
+        sleep(1);
+    }
+    fprintf(stderr, "*** start tx critical section ***\n");
+    ev_notify--;
+    fprintf(stderr, "foo desc handler\n");
+    virtio_queue_notify_handler(vsnd, 2, virtio_snd_foo_desc_handler);
+    fprintf(stderr, "*** end tx cirtical section ***\n");
+    pthread_mutex_unlock(&virtio_snd_mutex);
+    return NULL;
+}
+
 static bool virtio_snd_reg_read(virtio_snd_state_t *vsnd,
                                 uint32_t addr,
                                 uint32_t *value)
@@ -985,8 +1012,9 @@ static bool virtio_snd_reg_write(virtio_snd_state_t *vsnd,
                 break;
             case VSND_QUEUE_TX:
                 fprintf(stderr, "TX start\n");
-                virtio_queue_notify_handler(vsnd, value,
-                                            virtio_snd_tx_desc_handler);
+                ev_notify++;
+                /*virtio_queue_notify_handler(vsnd, value,
+                                            virtio_snd_foo_desc_handler);*/
                 sleep(1);
                 fprintf(stderr, "TX end\n");
                 break;
@@ -1024,8 +1052,6 @@ void virtio_snd_read(hart_t *vm,
                      uint8_t width,
                      uint32_t *value)
 {
-    fprintf(stderr, "=== start read lock ===\n");
-    pthread_mutex_lock(&virtio_snd_mutex);
     switch (width) {
     case RV_MEM_LW:
         if (!virtio_snd_reg_read(vsnd, addr >> 2, value))
@@ -1042,18 +1068,13 @@ void virtio_snd_read(hart_t *vm,
         vm_set_exception(vm, RV_EXC_ILLEGAL_INSN, 0);
         break;
     }
-    cnt++;
-    fprintf(stderr, "=== end read lock count %d ===\n", cnt);
-    pthread_mutex_unlock(&virtio_snd_mutex);
 }
 void virtio_snd_write(hart_t *vm,
                       virtio_snd_state_t *vsnd,
                       uint32_t addr,
                       uint8_t width,
                       uint32_t value)
 {
-    fprintf(stderr, "=== start write lock ===\n");
-    pthread_mutex_lock(&virtio_snd_mutex);
     switch (width) {
     case RV_MEM_SW:
         if (!virtio_snd_reg_write(vsnd, addr >> 2, value))
@@ -1067,9 +1088,6 @@ void virtio_snd_write(hart_t *vm,
         vm_set_exception(vm, RV_EXC_ILLEGAL_INSN, 0);
         break;
     }
-    cnt++;
-    fprintf(stderr, "=== end write lock count %d ===\n", cnt);
-    pthread_mutex_unlock(&virtio_snd_mutex);
 }
 
 bool virtio_snd_init(virtio_snd_state_t *vsnd)
@@ -1090,5 +1108,12 @@ bool virtio_snd_init(virtio_snd_state_t *vsnd)
     PRIV(vsnd)->controls =
         0; /* virtio-snd device does not support control elements */
 
+    ev_notify = 0;
+    pthread_t tid;
+    if(pthread_create(&tid, NULL, func, vsnd) != 0) {
+        fprintf(stderr, "cannot create TX thread\n");
+        return false;
+    }
+
     return true;
 }