This patch makes Stockfish search same depth again if > 60% of optimum time is
already used, instead of trying the next iteration. The idea is that the next
iteration will generally take about the same amount of time as has already been
used in total. When we are likely to begin the last iteration, as judged by total
time taken so far > 0.6 * optimum time, searching the last depth again instead of
increasing the depth still helps the other threads in lazy SMP and prepares better
move ordering for the next moves.
STC :
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 13436 W: 2695 L: 2558 D: 8183
Ptnml(0-2): 222, 1538, 3087, 1611, 253
https://tests.stockfishchess.org/tests/view/
5e1618a761fe5f83a67dd964
LTC :
LLR: 2.94 (-2.94,2.94) {0.00,2.00}
Total: 32160 W: 4261 L: 4047 D: 23852
Ptnml(0-2): 211, 2988, 9448, 3135, 247
https://tests.stockfishchess.org/tests/view/
5e162ca061fe5f83a67dd96d
The code was revised as suggested by @vondele for multithreading:
STC (8 threads):
LLR: 2.95 (-2.94,2.94) {0.00,2.00}
Total: 16640 W: 2049 L: 1885 D: 12706
Ptnml(0-2): 119, 1369, 5158, 1557, 108
https://tests.stockfishchess.org/tests/view/
5e19826a2cc590e03c3c2f52
LTC (8 threads):
LLR: 2.95 (-2.94,2.94) {-1.00,3.00}
Total: 16536 W: 2758 L: 2629 D: 11149
Ptnml(0-2): 182, 1758, 4296, 1802, 224
https://tests.stockfishchess.org/tests/view/
5e18b91a27dab692fcf9a140
Thanks to those discussing Stockfish lazy SMP on fishcooking which made me
try this, and to @vondele for suggestions and doing related tests.
See full discussion in the pull request thread:
https://github.com/official-stockfish/Stockfish/pull/2482
Bench:
4586187
Lucas Braesch (lucasart)
Lyudmil Antonov (lantonov)
Maciej Żenczykowski (zenczykowski)
+Malcolm Campbell (xoto10)
Mark Tenzer (31m059)
marotear
Matthew Lai (matthewlai)
Uri Blass (uriblass)
Vince Negri (cuddlestmonkey)
-# Additionally, we acknowledge the authors of fishtest,
-# an essential framework for the development of Stockfish:
+
+# Additionally, we acknowledge the authors and maintainer of fishtest,
+# an amazing and essential framework for the development of Stockfish!
+#
# https://github.com/glinscott/fishtest/blob/master/AUTHORS
+
+
+
+
contempt = (us == WHITE ? make_score(ct, ct / 2)
: -make_score(ct, ct / 2));
+ int searchAgainCounter = 0;
+
// Iterative deepening loop until requested to stop or the target depth is reached
while ( ++rootDepth < MAX_PLY
&& !Threads.stop
size_t pvFirst = 0;
pvLast = 0;
+ if (!Threads.increaseDepth)
+ searchAgainCounter++;
+
// MultiPV loop. We perform a full root search for each PV line
for (pvIdx = 0; pvIdx < multiPV && !Threads.stop; ++pvIdx)
{
int failedHighCnt = 0;
while (true)
{
- Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt);
+ Depth adjustedDepth = std::max(1, rootDepth - failedHighCnt - searchAgainCounter);
bestValue = ::search<PV>(rootPos, ss, alpha, beta, adjustedDepth, false);
// Bring the best move to the front. It is critical that sorting
else
Threads.stop = true;
}
+ else if ( Threads.increaseDepth
+ && Time.elapsed() > Time.optimum() * fallingEval * reduction * bestMoveInstability * 0.6)
+ Threads.increaseDepth = false;
+ else
+ Threads.increaseDepth = true;
}
mainThread->iterValue[iterIdx] = bestValue;
main()->wait_for_search_finished();
main()->stopOnPonderhit = stop = false;
+ increaseDepth = true;
main()->ponder = ponderMode;
Search::Limits = limits;
Search::RootMoves rootMoves;
uint64_t nodes_searched() const { return accumulate(&Thread::nodes); }
uint64_t tb_hits() const { return accumulate(&Thread::tbHits); }
- std::atomic_bool stop;
+ std::atomic_bool stop, increaseDepth;
private:
StateListPtr setupStates;