From dac1bcab9007e0fe4c73fda4d6e5ac5b9add435c Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Mon, 25 Jan 2010 19:48:10 +0100 Subject: [PATCH 1/1] Small split() cleanup Unify start loop for master and slave threads. Also guarantee that all the 'stop' flags are set to false before first slave is started, should be no harm because only master thread can reset 'stop' flag of slaves to true, so should be no race but better safe then sorry. Signed-off-by: Marco Costalba --- src/search.cpp | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) diff --git a/src/search.cpp b/src/search.cpp index 96b84423..d54c7ebd 100644 --- a/src/search.cpp +++ b/src/search.cpp @@ -2993,6 +2993,7 @@ namespace { splitPoint->slaves[i] = 0; Threads[master].idle = false; + Threads[master].stop = false; Threads[master].splitPoint = splitPoint; // Allocate available threads setting idle flag to false @@ -3000,6 +3001,7 @@ namespace { if (thread_is_available(i, master)) { Threads[i].idle = false; + Threads[i].stop = false; Threads[i].splitPoint = splitPoint; splitPoint->slaves[i] = 1; splitPoint->cpus++; @@ -3010,22 +3012,14 @@ namespace { // We can release the lock because master and slave threads are already booked lock_release(&MPLock); - // Copy the tail of current search stack to the master thread - memcpy(splitPoint->sstack[master] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack)); - // Tell the threads that they have work to do. This will make them leave - // their idle loop. Also copy search stack tail for each slave thread. + // their idle loop. But before copy search stack tail for each thread. for (int i = 0; i < ActiveThreads; i++) - { - if (splitPoint->slaves[i]) - memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack)); - if (i == master || splitPoint->slaves[i]) { - Threads[i].stop = false; + memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 3 * sizeof(SearchStack)); Threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop() } - } // Everything is set up. The master thread enters the idle loop, from // which it will instantly launch a search, because its workIsWaiting -- 2.39.2