When exiting wake up all threads at once

It seems we have a very rare crash under Linux, once
every 10K games without this patch.

Is faster to wake up all the threads, especially on SMP,
where the threads can then exit in parallel while the main
thread is waiting for the next one to terminate.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/thread.cpp b/src/thread.cpp
index 8269dcf3d50029d2e4e355a8da8c345b48ddee80..d845fdf2e4183f2fdaa10bb656b66d1ab6439749 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -192,14 +192,19 @@ void ThreadsManager::init() {
 
 void ThreadsManager::exit() {
 
 
 void ThreadsManager::exit() {
 

+  // Wake up all the slave threads at once. This is faster than "wake and wait"
+  // for each thread and avoids a rare crash once every 10K games under Linux.
+  for (int i = 1; i < MAX_THREADS; i++)
+  {
+      threads[i].do_terminate = true;
+      threads[i].wake_up();
+  }
+

   for (int i = 0; i < MAX_THREADS; i++)
   {
   for (int i = 0; i < MAX_THREADS; i++)
   {

-      // Wake up all the slave threads and wait for termination

       if (i != 0)
       {
       if (i != 0)
       {

-          threads[i].do_terminate = true;
-          threads[i].wake_up();
-
+          // Wait for slave termination

 #if defined(_MSC_VER)
           WaitForSingleObject(threads[i].handle, 0);
           CloseHandle(threads[i].handle);
 #if defined(_MSC_VER)
           WaitForSingleObject(threads[i].handle, 0);
           CloseHandle(threads[i].handle);