We cannot set do_sleep flag of main thread before
"bestmove" is sent to GUI, otherwise GUI could send
immediately the next "go" command that triggers
start_thinking() and because do_sleep is set UI
thread resets the flag to launch a new search. But
when shortly after main thread returns to main_loop()
flag is incorrectly reset and main thread goes to sleep
hanging the engine.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
void ThreadsManager::wake_up() {
void ThreadsManager::wake_up() {
- for (int i = 0; i < size(); i++)
+ for (int i = 1; i < size(); i++) // Main thread is already running
{
threads[i]->do_sleep = false;
{
threads[i]->do_sleep = false;
-// sleep() is called after the search to ask threads to wait on sleep condition
+// sleep() is called after the search to ask all the threads but the main to go
+// waiting on a sleep condition.
void ThreadsManager::sleep() {
void ThreadsManager::sleep() {
- for (int i = 0; i < size(); i++)
- threads[i]->do_sleep = true;
+ for (int i = 1; i < size(); i++) // Main thread will go to sleep by itself
+ threads[i]->do_sleep = true; // to avoid a race with start_thinking()