From: Marco Costalba <mcostalba@gmail.com>
Date: Mon, 26 Sep 2011 05:07:11 +0000 (+0100)
Subject: When exiting wake up all threads at once
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=83d8fe2d59bad718de70b00ac2c8fddfadda76b5;hp=63a04134d0841bb362f42d600faf614038fff494;ds=sidebyside

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 8269dcf3..d845fdf2 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -192,14 +192,19 @@ void ThreadsManager::init() {
 
 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++)
   {
-      // Wake up all the slave threads and wait for termination
       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);