Use threading to further decrease benchmark running time.

binary-trees.dylan

@@ -7,7 +7,9 @@ end library;
 
 define module binary-trees
   use common-dylan, exclude: { format-to-string };
+  use format;
   use format-out;
+  use threads;
 end module;
 
 define constant <tree> = false-or(<node>);
@@ -43,14 +45,27 @@ begin
 
   let long-lived-tree = build(max-depth);
 
-  for (d from min-depth to max-depth by 2)
+  let size = floor/(max-depth - min-depth, 2) + 1;
+  let messages = make(<vector>, size: size);
+  let threads = make(<vector>, size: size);
+  for (i from 0,
+       d from min-depth to max-depth by 2)
     let iterations = ash(1, max-depth - d + min-depth);
-    for (i from 1 to iterations,
-         c = 0 then c + build(d).check)
-    finally
-      format-out("%d\t trees of depth %d\t check: %d\n", iterations, d, c);
-    end for;
+    local method loop()
+            for (_ from 1 to iterations,
+                 c = 0 then c + build(d).check)
+            finally
+              messages[i] := format-to-string("%d\t trees of depth %d\t check: %d", iterations, d, c);
+            end for;
+          end;
+    threads[i] := make(<thread>, function: loop);
   end for;
+  for (thread in threads)
+    thread & join-thread(thread);
+  end;
+  for (message in messages)
+    format-out("%s\n", message);
+  end;
 
   format-out("long lived tree of depth %d\t check: %d\n",
              max-depth, long-lived-tree.check);