From 4a71c862702c05b3c56e902f4675fdf68041710b Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Sun, 7 Aug 2011 19:56:53 +0100 Subject: [PATCH] Retire Thread::BOOKED Start a slave as soon as is allocated. No functional change with faked split. Regression tested the full split() series and after 2000 games no regression and no crash. Signed-off-by: Marco Costalba --- src/thread.cpp | 38 +++++++++++++++----------------------- src/thread.h | 3 +-- 2 files changed, 16 insertions(+), 25 deletions(-) diff --git a/src/thread.cpp b/src/thread.cpp index 24fbebc0..f5bd50ea 100644 --- a/src/thread.cpp +++ b/src/thread.cpp @@ -283,18 +283,23 @@ Value ThreadsManager::split(Position& pos, SearchStack* ss, Value alpha, Value b int workersCnt = 1; // At least the master is included - // Try to allocate available threads setting state to Thread::BOOKED, this - // must be done under lock protection to avoid concurrent allocation of - // the same slave by another master. + // Try to allocate available threads and ask them to start searching setting + // the state to Thread::WORKISWAITING, this must be done under lock protection + // to avoid concurrent allocation of the same slave by another master. lock_grab(&threadsLock); for (i = 0; !Fake && i < activeThreads && workersCnt < maxThreadsPerSplitPoint; i++) if (i != master && threads[i].is_available_to(master)) { - threads[i].state = Thread::BOOKED; - threads[i].splitPoint = &splitPoint; - splitPoint.is_slave[i] = true; workersCnt++; + splitPoint.is_slave[i] = true; + threads[i].splitPoint = &splitPoint; + + // This makes the slave to exit from idle_loop() + threads[i].state = Thread::WORKISWAITING; + + if (useSleepingThreads) + threads[i].wake_up(); } lock_release(&threadsLock); @@ -303,27 +308,14 @@ Value ThreadsManager::split(Position& pos, SearchStack* ss, Value alpha, Value b if (!Fake && workersCnt == 1) return bestValue; - masterThread.activeSplitPoints++; masterThread.splitPoint = &splitPoint; - - // Tell the threads that they have some work to do. This will make them leave - // their idle loop. - for (i = 0; i < activeThreads; i++) - if (i == master || splitPoint.is_slave[i]) - { - assert(i == master || threads[i].state == Thread::BOOKED); - - // This makes the slave to exit from idle_loop() - threads[i].state = Thread::WORKISWAITING; - - if (useSleepingThreads && i != master) - threads[i].wake_up(); - } + masterThread.activeSplitPoints++; + masterThread.state = Thread::WORKISWAITING; // Everything is set up. The master thread enters the idle loop, from // which it will instantly launch a search, because its state is - // THREAD_WORKISWAITING. We send the split point as a second parameter to the - // idle loop, which means that the main thread will return from the idle + // Thread::WORKISWAITING. We send the split point as a second parameter to + // the idle loop, which means that the main thread will return from the idle // loop when all threads have finished their work at this split point. idle_loop(master, &splitPoint); diff --git a/src/thread.h b/src/thread.h index 6ee07d34..cdb0d9b8 100644 --- a/src/thread.h +++ b/src/thread.h @@ -70,8 +70,7 @@ struct Thread { INITIALIZING, // Thread is initializing itself SEARCHING, // Thread is performing work AVAILABLE, // Thread is waiting for work - BOOKED, // Other thread (master) has booked us as a slave - WORKISWAITING, // Master has ordered us to start + WORKISWAITING, // Master has ordered us to start searching TERMINATED // We are quitting and thread is terminated }; -- 2.39.2