From: Marco Costalba <mcostalba@gmail.com>
Date: Thu, 19 Feb 2015 22:12:59 +0000 (+0100)
Subject: Clarify we don't late join with only 2 threads
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=667f35073773653ef8d05260536516fffb2d3faa;ds=sidebyside

Clarify we don't late join with only 2 threads

Thanks to Gary for pointing this out.

No functional change.
---

diff --git a/src/search.cpp b/src/search.cpp
index 12ed7599..15b93a72 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1604,8 +1604,10 @@ void Thread::idle_loop() {
               {
                   assert(this != Threads[i]);
                   assert(!(this_sp && this_sp->slavesMask.none()));
+                  assert(Threads.size() > 2);
 
-                  // Compute the recursive split points chain size
+                  // Prefer to join to SP with few parents to reduce the probability
+                  // that a cut-off occurs above us, and hence we waste our work.
                   int level = -1;
                   for (SplitPoint* spp = Threads[i]->activeSplitPoint; spp; spp = spp->parentSplitPoint)
                       level++;