I ran a copy of my in-house Stockfish compile (Stockfish, 16 threads) against its copy (Stockfish_2015-11-03_x64_bmi2_MinGW, 8 threads),
no ponder, no Syzygy, 256MB hash, on a Corei7-5960X (8 cores, hyperthreading on), 20"+0.3" TC, on Marijan's Arena-Blitzer, with the following results
-----------------Stockfish-----------------
Stockfish - Stockfish_2015-11-03_x64_bmi2_MinGW : 509.5/1000 148-129-723 (===0==10=0=01==1====1==0====0====101=0===1====1======0=0=0=0==101=1======01=0=0====1=====1=11=10===0==1=====0========0=1======1001=01=======1===1===01=
==0=01==1==11=========0=========1=0=====0========
=0==0==0==10==111====1=====1===0=======0==0=11==1========0======1=======0==01=10======1========1======0======0======0==========1=11=======0=1======0======1100===0==10===0===0===1=0=1=====0=====1=1=0============1=1==110===1==0===1==1=1===11======1=0=00
=======10===1========0=1==1========1========110==
===0==1===1==1=111==10========1====1====1=1====1==1============0==1=0======1====1===0====0===0======10======0==00===011==0=11=110=========1=======11===01===10======1=1==01=====10=0======0=10==01===1==1==1=====0====1==010==1====110====00======0======0==1====1==1=1===1==0==0===0=====1==1=====1======1===0
1===010=01=10=======0=======0======01=================0==1===1====1====0=====1====0==00========0===0
1===0======0====0====1=1=1=0=========1==0====1==0====0==001====01=0==10==10====0010==1===1=1=1000) 51% +7
-----------------Stockfish_2015-11-03_x64_bmi2_MinGW-----------------
Stockfish_2015-11-03_x64_bmi2_MinGW - Stockfish : 490.5/1000 129-148-723 (===1==01=1=10==0====0==1====1====010=1===0====0======1=1=1=1==010=0======10=1=1====0=====0=00=01===1==0=====1========1=0======0110=10=======0===0===10===1=10==0==00=========1=========0=1=====1========
=1==1==1==01==000====0=====0===1=======1==1=00==0========1======0=======1==10=01======0========0======1======1======1==========0=00=======1=0======1=
=====0011===1==01===1===1===0=1=0=====1=====0=0=1============0=0==001===0==1===0==0=0===00======0=1=11
=======01===0========1=0==0========0========001=====1==0===0==0=000==01========0====0====0=0====0==0============1==0=1======0====0===1====1===1======
01======1==11===100==1=00=001=========0=======00===10===01======0=0==10=====01=1======1=01==10===0==0=
=0=====1====0==101==0====001====11======1======1==0====0==0=0===0==1==1===1=====0==0=====0======0===10===101=10=01=======1=======1======10=============
====1==0===0====0====1=====0====1==11========1===10===1======1====1====0=0=0=1=========0==1====0==1====1==110====10=1==01==01====1101==0===0=0=0111) 49% -7
Is the apparent advantage of 16 threads over 8 due to the benefits of LazySMP?
Stockfish now benefits from hyperthreading
Moderators: hgm, Rebel, chrisw
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- Full name: Álvaro Begué (RuyDos)
Re: Stockfish now benefits from hyperthreading
I get a LOS of 0.87319, which means your result is not very significant. A p-value of 0.12 is not good enough even for social science.
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- Location: Redmond, WA USA
Re: Stockfish now benefits from hyperthreading
The thing that is very interesting is that it is not clearly worse.
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- Joined: Mon Jan 28, 2013 2:51 pm
Re: Stockfish now benefits from hyperthreading
Whoever is interested is most welcome to run more games. As Dann Corbit pointed out correctly, hyperthreading used to make performance clearly worse in the past, so I am delighted to see that not happen in this one experiment.
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- Joined: Wed Mar 08, 2006 8:30 pm
Re: Stockfish now benefits from hyperthreading
With 95% (2 sigma) error-bar, the result reads as : (509.5 ± 17) / 1000Gusev wrote:Stockfish - Stockfish_2015-11-03_x64_bmi2_MinGW : 509.5/1000 148-129-723
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Ditto Cheng 4 Re: Stockfish now benefits from hyperthreading
As a follow-up, I ran 1000 games of Cheng 4, 8 threads vs. 4 threads on a 4-core i7-930. The 8-thread Cheng 4 won,
-----------------Cheng4_x64-----------------
Cheng4_x64 - Cheng4_x64 - Copy : 523.0/1000 236-190-574 (1=010=1=0101=00=1==01===010==001=10=0==0=====111=11=100=11=1=01=111001011=0===11==01===10======0=110=1==0=00=10====11=0101====011=01=1====1=1=====110=====10====
==1100====1==1==101====1=1=0=1=11==1========0===0====1111=11=00==0==1====101==0=1====1=1====0=00=====11=000========01===10==0=10=====10===0==1==0==00==1=0
=1===1=01=011===111======1011=0===11====0=1=00010=0001==0=1====0100=====0==0=======0==0=========00==11=1=10=0====1===0=1=10110=110==0=100==0=100=01=1=10=0=11=
=====1==1====1=1=0=1=01======1=01=0=0=01=1=1010====1010==1=1=1==001===11=10==101=01=1=01110=01==0===0===1=0=110===0=1011=01==11==01=00===1==1===11=10=11===1===0=10====0==========1=0==0=1========1==========1=1====0===01=011101=1=0=0=1===01010=======11==1==1=1=0==
101=10=0=00=0===1110==0=================1=0=1=1=01=1=1===1======1=====01=11=0===11=11=1=01=0===========
===0111=00===0==01==========1===1=111===01===0===10===1=0101=1=011======0====1===0===100===1=====0=0======0010=1=00====0==110===010=====1==01==1=1=0==1=00====0=001) 52% +14
-----------------Cheng4_x64 - Copy-----------------
Cheng4_x64 - Copy - Cheng4_x64 : 477.0/1000 190-236-574 (0=101=0=1010=11=0==10===101==110=01=1==1=====000=00=011=00=0=10=000110100=1===00==10===01======1=001=0==1=11=01====00=1010====100=10=0====0=0=====001=====01====
==0011====0==0==010====0=0=1=0=00==0========1===1====0000=00=11==1==0====010==1=0====0=0====1=11=====00=111========10===01==1=01=====01===1==0==1==11==0=1
=0===0=10=100===000======0100=1===00====1=0=11101=1110==1=0====1011=====1==1=======1==1=========11==00=0
=01=1====0===1=0=01001=001==1=011==1=011=10=0=01=1=00======0==0====0=0=1=0=10======0=10=1=1=10=0=0101====0101==0=0=0==110===00=01==010=10=0=10001=10==1===1===0=
1=001===1=0100=10==00==10=11===0==0===00=01=00===0===1=01====1==========0=1==1=0========0==========0=0=
===1===10=100010=0=1=1=0===10101=======00==0==0=0=1==
010=01=1=11=1===0001==1=================0=1=0=0=10=0=0===0======0=====10=00=1===00=00=0=10=1==============1000=11===1==10==========0===0=000===10===1===01===0=1010=0=100======1====0===1===011===0=====1=1==
====1101=0=11====1==001===101=====0==10==0=0=1==0=11====1=110) 48% -14
-----------------Cheng4_x64-----------------
Cheng4_x64 - Cheng4_x64 - Copy : 523.0/1000 236-190-574 (1=010=1=0101=00=1==01===010==001=10=0==0=====111=11=100=11=1=01=111001011=0===11==01===10======0=110=1==0=00=10====11=0101====011=01=1====1=1=====110=====10====
==1100====1==1==101====1=1=0=1=11==1========0===0====1111=11=00==0==1====101==0=1====1=1====0=00=====11=000========01===10==0=10=====10===0==1==0==00==1=0
=1===1=01=011===111======1011=0===11====0=1=00010=0001==0=1====0100=====0==0=======0==0=========00==11=1=10=0====1===0=1=10110=110==0=100==0=100=01=1=10=0=11=
=====1==1====1=1=0=1=01======1=01=0=0=01=1=1010====1010==1=1=1==001===11=10==101=01=1=01110=01==0===0===1=0=110===0=1011=01==11==01=00===1==1===11=10=11===1===0=10====0==========1=0==0=1========1==========1=1====0===01=011101=1=0=0=1===01010=======11==1==1=1=0==
101=10=0=00=0===1110==0=================1=0=1=1=01=1=1===1======1=====01=11=0===11=11=1=01=0===========
===0111=00===0==01==========1===1=111===01===0===10===1=0101=1=011======0====1===0===100===1=====0=0======0010=1=00====0==110===010=====1==01==1=1=0==1=00====0=001) 52% +14
-----------------Cheng4_x64 - Copy-----------------
Cheng4_x64 - Copy - Cheng4_x64 : 477.0/1000 190-236-574 (0=101=0=1010=11=0==10===101==110=01=1==1=====000=00=011=00=0=10=000110100=1===00==10===01======1=001=0==1=11=01====00=1010====100=10=0====0=0=====001=====01====
==0011====0==0==010====0=0=1=0=00==0========1===1====0000=00=11==1==0====010==1=0====0=0====1=11=====00=111========10===01==1=01=====01===1==0==1==11==0=1
=0===0=10=100===000======0100=1===00====1=0=11101=1110==1=0====1011=====1==1=======1==1=========11==00=0
=01=1====0===1=0=01001=001==1=011==1=011=10=0=01=1=00======0==0====0=0=1=0=10======0=10=1=1=10=0=0101====0101==0=0=0==110===00=01==010=10=0=10001=10==1===1===0=
1=001===1=0100=10==00==10=11===0==0===00=01=00===0===1=01====1==========0=1==1=0========0==========0=0=
===1===10=100010=0=1=1=0===10101=======00==0==0=0=1==
010=01=1=11=1===0001==1=================0=1=0=0=10=0=0===0======0=====10=00=1===00=00=0=10=1==============1000=11===1==10==========0===0=000===10===1===01===0=1010=0=100======1====0===1===011===0=====1=1==
====1101=0=11====1==001===101=====0==10==0=0=1==0=11====1=110) 48% -14
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- Joined: Mon Jan 28, 2013 2:51 pm
Re: Ditto Cheng 4 Re: Stockfish now benefits from hyperthrea
Likewise, Cheng 4 (16 threads) won over Cheng 4 Copy (8 threads) on i7-5960X,
-----------------Cheng4_x64-----------------
Cheng4_x64 - Cheng4_x64_Copy : 519.0/1000 215-177-608 (1===00=====1==0==0=1====0=01==001=0=010==1=0=1111000=1==00===01==0=10========1=00=01==1=11=0==1==1===110====11=0==0==1=101=100====00===11====11===110===1===
0111==0=1======0=01==1===01====0=11==0=0=0=10===110010===1110==1==0===11==1==101==1==========1=0==1=0===1=====1=1==0=1==011=1==0===1==0=0====1==1==01==0=11=
1=0======111=====00=01=0=1=001=====10==0011==1==0=1======1==0=1=======1===01====1====0=10=011010============0=======0=01===0=01===0===101=======1====0===
==1=1==1=0==1=1====11==010========1==01===10==110010====01===01=====10===0===000=0==1=11===1=00===0==1=1===1=0=111===1======0===00=====01=1==1==10=====0==1
01=0=1=0==110====1====0==0====1===0=1010=1==1====1=1001101===========1=00==1==11==1===010=1======1=1==0=====01===1==========0=1=0=10========0011=010==00==1
=0=0=======1==1===1=1===1=1000==1====0=01==11==1=00==1===1=101==1==0===1====11==11=====0=1===0=0=000==10=10==1===0==1=====0====10==01=1==0==11==101==0=====
=0==0=====01======1=00===0=1=1111===1===0=====0=0=1001==00=1=1011=11=1) 52% +14
-----------------Cheng4_x64_Copy-----------------
Cheng4_x64_Copy - Cheng4_x64 : 481.0/1000 177-215-608 (0===11=====0==1==1=0====1=10==110=1=101==0=1=0000111=0==11===10==1=01========0=11=10==0=00=1==0==0===001====00=1==1==0=010=011====11===00====00===001===0===
1000==1=0======1=10==0===10====1=00==1=1=1=01===001101===0001==0==1===00==0==010==0==========0=1==0=1===0=====0=0==1=0==100=0==1===0==1=1====0==0==10==1=00=
0=1======000=====11=10=1=0=110=====01==1100==0==1=0======0==1=0=======0===10====0====1=01=100101============1=======1=10===1=10===1===010=======0====1===
==0=0==0=1==0=0====00==101========0==10===01==001101====10===10=====01===1===111=1==0=00===0=11===1==0=0===0=1=000===0======1===11=====10=0==0==01=====1==0
10=1=0=1==001====0====1==1====0===1=0101=0==0====0=0110010===========0=11==0==00==0===101=0======0=0==1=====10===0==========1=0=1=01========1100=101==11==0
=1=1=======0==0===0=0===0=0111==0====1=10==00==0=11==0===0=010==0==1===0====00==00=====1=0===1=1=111==01=01==0===1==0=====1====01==10=0==1==00==010==1=====
=1==1=====10======0=11===1=0=0000===0===1=====1=1=0110==11=0=0100=00=0) 48% -14
-----------------Cheng4_x64-----------------
Cheng4_x64 - Cheng4_x64_Copy : 519.0/1000 215-177-608 (1===00=====1==0==0=1====0=01==001=0=010==1=0=1111000=1==00===01==0=10========1=00=01==1=11=0==1==1===110====11=0==0==1=101=100====00===11====11===110===1===
0111==0=1======0=01==1===01====0=11==0=0=0=10===110010===1110==1==0===11==1==101==1==========1=0==1=0===1=====1=1==0=1==011=1==0===1==0=0====1==1==01==0=11=
1=0======111=====00=01=0=1=001=====10==0011==1==0=1======1==0=1=======1===01====1====0=10=011010============0=======0=01===0=01===0===101=======1====0===
==1=1==1=0==1=1====11==010========1==01===10==110010====01===01=====10===0===000=0==1=11===1=00===0==1=1===1=0=111===1======0===00=====01=1==1==10=====0==1
01=0=1=0==110====1====0==0====1===0=1010=1==1====1=1001101===========1=00==1==11==1===010=1======1=1==0=====01===1==========0=1=0=10========0011=010==00==1
=0=0=======1==1===1=1===1=1000==1====0=01==11==1=00==1===1=101==1==0===1====11==11=====0=1===0=0=000==10=10==1===0==1=====0====10==01=1==0==11==101==0=====
=0==0=====01======1=00===0=1=1111===1===0=====0=0=1001==00=1=1011=11=1) 52% +14
-----------------Cheng4_x64_Copy-----------------
Cheng4_x64_Copy - Cheng4_x64 : 481.0/1000 177-215-608 (0===11=====0==1==1=0====1=10==110=1=101==0=1=0000111=0==11===10==1=01========0=11=10==0=00=1==0==0===001====00=1==1==0=010=011====11===00====00===001===0===
1000==1=0======1=10==0===10====1=00==1=1=1=01===001101===0001==0==1===00==0==010==0==========0=1==0=1===0=====0=0==1=0==100=0==1===0==1=1====0==0==10==1=00=
0=1======000=====11=10=1=0=110=====01==1100==0==1=0======0==1=0=======0===10====0====1=01=100101============1=======1=10===1=10===1===010=======0====1===
==0=0==0=1==0=0====00==101========0==10===01==001101====10===10=====01===1===111=1==0=00===0=11===1==0=0===0=1=000===0======1===11=====10=0==0==01=====1==0
10=1=0=1==001====0====1==1====0===1=0101=0==0====0=0110010===========0=11==0==00==0===101=0======0=0==1=====10===0==========1=0=1=01========1100=101==11==0
=1=1=======0==0===0=0===0=0111==0====1=10==00==0=11==0===0=010==0==1===0====00==00=====1=0===1=1=111==01=01==0===1==0=====1====01==10=0==1==00==010==1=====
=1==1=====10======0=11===1=0=0000===0===1=====1=1=0110==11=0=0100=00=0) 48% -14
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Re: Ditto Cheng 4 Re: Stockfish now benefits from hyperthrea
This is a very surprising result.
NPS clearly should not be expected to increase.
With double the threads, there should be greatly increased SMP loss.
There must be some other unaccounted affect here.
I would love to see a logical explanation for it.
NPS clearly should not be expected to increase.
With double the threads, there should be greatly increased SMP loss.
There must be some other unaccounted affect here.
I would love to see a logical explanation for it.
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- Joined: Tue Mar 09, 2010 3:46 pm
- Location: New York
- Full name: Álvaro Begué (RuyDos)
Re: Ditto Cheng 4 Re: Stockfish now benefits from hyperthrea
Why shouldn't NPS increase? The promise of hyper-threading is that you can effectively run up to two threads per core, with some degradation. This degradation has traditionally been too great to compensate for the sub-linear scaling in parallel-search performance with the number of threads. It could be that recent i7 processors are doing hyper-threading so well that it now does compensate. Or perhaps parallel search now scales better with number of threads?Dann Corbit wrote:This is a very surprising result.
NPS clearly should not be expected to increase.
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Re: Ditto Cheng 4 Re: Stockfish now benefits from hyperthrea
Even if the context switch occurs with zero overhead, it is astonishing to imagine that somehow the single core can do more work by simply switching context. That is all that it is doing.