Stockfish Claiming Big Elo gains at VLTC and more threads.

It would be great if Stockfish is fixing the thread and VLTC issues.

We will test and see how it performs in real games.

Author: Michael Chaly
Date: Fri Feb 24 20:14:44 2023 +0100
Timestamp: 1677266084

Search tuning at very long time control

This patch is a result of tuning session of approximately 100k games at 120+1.2.
Biggest changes are in extensions, stat bonus and depth reduction for nodes without a tt move.

Failed STC:
https://tests.stockfishchess.org/tests/view/63f72c72e74a12625bcd7938
LLR: -2.94 (-2.94,2.94) <0.00,2.00>
Total: 13872 W: 3535 L: 3769 D: 6568 Elo -5.86
Ptnml(0-2): 56, 1621, 3800, 1419, 40

Close to neutral at LTC:
https://tests.stockfishchess.org/tests/view/63f738f5e74a12625bcd7b8a
Elo: 0.80 +-1.2 (95%) LOS: 90.0%
Total: 60000 W: 16213 L: 16074 D: 27713 Elo +0.80
Ptnml(0-2): 24, 5718, 18379, 5853, 26
nElo: 1.82 +-2.8 (95%) PairsRatio: 1.02

Passed 180+1.8 VLTC:
https://tests.stockfishchess.org/tests/view/63f868f3e74a12625bcdb33e
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 15864 W: 4449 L: 4202 D: 7213 Elo +5.41
Ptnml(0-2): 1, 1301, 5083, 1544, 3

Passed 60+0.6 8 threads SMP VLTC:
https://tests.stockfishchess.org/tests/view/63f8a5d6e74a12625bcdbdb3
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 6288 W: 1821 L: 1604 D: 2863 Elo +11.99
Ptnml(0-2): 0, 402, 2123, 619, 0

closes https://github.com/official-stockfish/Stockfish/pull/4406

bench 4705194

mwyoung wrote:

It would be great if Stockfish is fixing the thread and VLTC issues.

We will test and see how it performs in real games.

Author: Michael Chaly
Date: Fri Feb 24 20:14:44 2023 +0100
Timestamp: 1677266084

Search tuning at very long time control

This patch is a result of tuning session of approximately 100k games at 120+1.2.
Biggest changes are in extensions, stat bonus and depth reduction for nodes without a tt move.

Failed STC:
https://tests.stockfishchess.org/tests/view/63f72c72e74a12625bcd7938
LLR: -2.94 (-2.94,2.94) <0.00,2.00>
Total: 13872 W: 3535 L: 3769 D: 6568 Elo -5.86
Ptnml(0-2): 56, 1621, 3800, 1419, 40

Close to neutral at LTC:
https://tests.stockfishchess.org/tests/view/63f738f5e74a12625bcd7b8a
Elo: 0.80 +-1.2 (95%) LOS: 90.0%
Total: 60000 W: 16213 L: 16074 D: 27713 Elo +0.80
Ptnml(0-2): 24, 5718, 18379, 5853, 26
nElo: 1.82 +-2.8 (95%) PairsRatio: 1.02

Passed 180+1.8 VLTC:
https://tests.stockfishchess.org/tests/view/63f868f3e74a12625bcdb33e
LLR: 2.95 (-2.94,2.94) <0.50,2.50>
Total: 15864 W: 4449 L: 4202 D: 7213 Elo +5.41
Ptnml(0-2): 1, 1301, 5083, 1544, 3

Passed 60+0.6 8 threads SMP VLTC:
https://tests.stockfishchess.org/tests/view/63f8a5d6e74a12625bcdbdb3
LLR: 2.94 (-2.94,2.94) <0.50,2.50>
Total: 6288 W: 1821 L: 1604 D: 2863 Elo +11.99
Ptnml(0-2): 0, 402, 2123, 619, 0

closes https://github.com/official-stockfish/Stockfish/pull/4406

bench 4705194

My bad maths says 400 days of tuning tests. 4 days per 100 threads. Difficult for the rest of us to compete with that.

Became time they invested in LTC testing, after all they have the hardware for it.

Benchmark test, and scaling using the AMD 5900HX CPU, 8 core 16 threads.
For Stockfish dev-20230224.

Setting and scores. [bench hash threads searchdepth]

bench 1024 1 30
518,702 ms.
2,377,606 nps.

bench 1024 2 30
406,518 ms.
4,920,720 nps.

bench 1024 4 30
364,875 ms.
9,699,987 nps.

bench 1024 8 30
361,231 ms.
18,020,574 nps.

bench 1024 16 30
444,305 ms.
24,462,641 nps.

Results.

Only a 44% speedup going from 1 to 8 cores. And again using more threads then cores is not recommended with Stockfish. Regardless of the huge speedup in nodes per second, 8 core solve time 361,231 ms. vs 16 thread solve time 444,305 ms.