From a1a7bc84da4a6f180179e437494dd485cba1711d Mon Sep 17 00:00:00 2001
From: Marco Costalba <mcostalba@gmail.com>
Date: Sat, 15 Mar 2014 21:13:43 +0100
Subject: [PATCH 1/1] Remove "Max Threads per Split Point" UCI option

Experimental patch to verify if drop of nps
in endgames at very long TC is due to this.

Suggested by Ronald de Man.

bench: 7451319
---
 polyglot.ini      |  1 -
 src/thread.cpp    | 13 ++++++-------
 src/thread.h      |  1 -
 src/ucioption.cpp |  1 -
 4 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/polyglot.ini b/polyglot.ini
index b851a33a..4e825f3c 100644
--- a/polyglot.ini
+++ b/polyglot.ini
@@ -30,7 +30,6 @@ Space = 100
 Aggressiveness = 100
 Cowardice = 100
 Min Split Depth = 0
-Max Threads per Split Point = 5
 Threads = 1
 Idle Threads Sleep = true
 Hash = 128
diff --git a/src/thread.cpp b/src/thread.cpp
index 9e96be6e..60c0ce71 100644
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -88,7 +88,7 @@ Thread::Thread() /* : splitPoints() */ { // Value-initialization bug in MSVC
   maxPly = splitPointsSize = 0;
   activeSplitPoint = NULL;
   activePosition = NULL;
-  idx = Threads.size();
+  idx = Threads.size(); // Starts from 0
 }
 
 
@@ -213,9 +213,8 @@ void ThreadPool::exit() {
 
 void ThreadPool::read_uci_options() {
 
-  maxThreadsPerSplitPoint = Options["Max Threads per Split Point"];
-  minimumSplitDepth       = Options["Min Split Depth"] * ONE_PLY;
-  size_t requested        = Options["Threads"];
+  minimumSplitDepth = Options["Min Split Depth"] * ONE_PLY;
+  size_t requested  = Options["Threads"];
 
   assert(requested > 0);
 
@@ -297,12 +296,12 @@ void Thread::split(Position& pos, const Stack* ss, Value alpha, Value beta, Valu
   activeSplitPoint = &sp;
   activePosition = NULL;
 
-  size_t slavesCnt = 1; // This thread is always included
+  int slavesCnt = 1; // This thread is always included
   Thread* slave;
 
-  while (    (slave = Threads.available_slave(this)) != NULL
-         && ++slavesCnt <= Threads.maxThreadsPerSplitPoint && !Fake)
+  while (!Fake && (slave = Threads.available_slave(this)) != NULL)
   {
+      ++slavesCnt;
       sp.slavesMask |= 1ULL << slave->idx;
       slave->activeSplitPoint = &sp;
       slave->searching = true; // Slave leaves idle_loop()
diff --git a/src/thread.h b/src/thread.h
index c9152b22..ddeb4902 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -166,7 +166,6 @@ struct ThreadPool : public std::vector<Thread*> {
 
   bool sleepWhileIdle;
   Depth minimumSplitDepth;
-  size_t maxThreadsPerSplitPoint;
   Mutex mutex;
   ConditionVariable sleepCondition;
   TimerThread* timer;
diff --git a/src/ucioption.cpp b/src/ucioption.cpp
index 68a57bd5..eefacb22 100644
--- a/src/ucioption.cpp
+++ b/src/ucioption.cpp
@@ -70,7 +70,6 @@ void init(OptionsMap& o) {
   o["Aggressiveness"]              = Option(100, 0, 200, on_eval);
   o["Cowardice"]                   = Option(100, 0, 200, on_eval);
   o["Min Split Depth"]             = Option(0, 0, 12, on_threads);
-  o["Max Threads per Split Point"] = Option(5, 4,  8, on_threads);
   o["Threads"]                     = Option(1, 1, MAX_THREADS, on_threads);
   o["Idle Threads Sleep"]          = Option(true);
   o["Hash"]                        = Option(32, 1, 16384, on_hash_size);
-- 
2.39.2