Issue #150 - Inefficient (but working) thread-join!

examples/threading/benchmarks/bv2string.scm

@@ -176,7 +176,7 @@
                (flush-output-port (current-output-port)))
 
     )))
-(define *running-threads* 0)
+(define *running-threads* '())
 (define m (make-mutex))
 
 (define (async-exec-multi! n thunk)
@@ -185,22 +185,27 @@
     (async-exec! thunk)))
 
 (define (async-exec! thunk)
-  (set! *running-threads* (+ *running-threads* 1)) ;; On main thread, so no lock
-  (thread-start!
-    (make-thread
-      (lambda ()
-        (thunk)
-        (mutex-lock! m)
-        (set! *running-threads* (- *running-threads* 1))
-        (mutex-unlock! m)))))
+  (let ((t (make-thread
+             (lambda ()
+               (mutex-lock! m)
+               (set! *running-threads* (cons (current-thread) *running-threads*))
+               (mutex-unlock! m)
+               (thunk))))) 
+    (thread-start! t)))
 
 (define (wait-for-all-async)
-  (let loop ((done #f))
-    (thread-sleep! 0)
+  (thread-sleep! 1) ;; TODO: not good enough, figure out a better solution
+  (let loop ()
+    (define t #f)
     (mutex-lock! m)
-    (if (= *running-threads* 0) (set! done #t))
+    (when (not (null? *running-threads*))
+      (set! t (car *running-threads*))
+      (set! *running-threads* (cdr *running-threads*)))
     (mutex-unlock! m)
-    (if (not done) (loop #f))))
+
+    (when t
+      (thread-join! t)
+      (loop))))
   
 ;;; The following code is appended to all benchmarks.
 

gc.c

@@ -1832,6 +1832,19 @@ void *collector_main(void *arg)
   return NULL;
 }
 
+/**
+ * @brief A high-resolution sleep function.
+ *
+ * @param  ms  Sleep time in milliseconds
+ */
+void gc_sleep_ms(int ms)
+{
+  struct timespec tim;
+  tim.tv_sec = 0;
+  tim.tv_nsec = ms * NANOSECONDS_PER_MILLISECOND;
+  nanosleep(&tim, NULL);
+}
+
 static pthread_t collector_thread;
 
 /**

include/cyclone/types.h

@@ -307,6 +307,7 @@ void gc_initialize(void);
 void gc_add_mutator(gc_thread_data * thd);
 void gc_remove_mutator(gc_thread_data * thd);
 int gc_is_mutator_active(gc_thread_data *thd);
+void gc_sleep_ms(int ms);
 gc_heap *gc_heap_create(int heap_type, size_t size, size_t max_size,
                         size_t chunk_size, gc_thread_data *thd);
 gc_heap *gc_heap_free(gc_heap *page, gc_heap *prev_page);

srfi/18.sld

@@ -120,7 +120,13 @@
       "(void *data, int argc, closure _, object k, object thread_data_opaque)"
       " gc_thread_data *td = (gc_thread_data *)(opaque_ptr(thread_data_opaque));
         set_thread_blocked(data, k);
-        pthread_join(td->thread_id, NULL);
+        /* Cannot join to detached thread! pthread_join(td->thread_id, NULL);*/
+        while (1) {
+          if (!gc_is_mutator_active(td)){
+            break;
+          }
+          gc_sleep_ms(250);
+        }
         return_thread_runnable(data, boolean_t);")
     (define (thread-join! t)
       (if (and (thread? t) (Cyc-opaque? (vector-ref t 2)))