New AMD Ryzen™ Threadripper™ PRO 3995WX (Windows and Multithreading Problem)

[Zerbinati]

Whenever Windows experiences more than 64 threads in a system, it separates those threads into processor groups. The way this is done is very rudimentary: of the enumerated cores and threads, the first 64 go into the first group, the second 64 go into the next group, and so on.
So I can only use 64 Threads of a group.
Would it be possible to insert the "set affinity" statement in the Stockfish code? (To use all 128 Threads)
I can to compile and test any possible solution
Thanks in advance
Marco

[syzygy]

I think Stockfish already does what you want. Did you try running it with >64 threads?

(I assume you want the threads to be spread over groups.)

[Zerbinati]

I think Stockfish already does what you want. Did you try running it with >64 threads?

(I assume you want the threads to be spread over groups.)

Hi Ronald
I would like to use 128 threads
performance
64 threads
CPU 65% only 64 threads 100%
128 threads
CPU 100% 128 threads 100%

but the nodes don't change, any increment from 64 to 128..
surely something is wrong





(also Komodo dragon increases the nodes from 64 to 128)

asmFishW work well

Code: Select all

asmFishW_2017-05-22_popcnt
setoption name LargePages value true
bench 1024 128 26
*** bench hash 1024 threads 128 depth 26 realtime 0 ***
info string hash set to 1024 MB page size 2048 KB
info string node 0 has threads 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 100 102 104 106 108 110 112 114 116 118 120 122 124 126
info string node 1 has threads 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 101 103 105 107 109 111 113 115 117 119 121 123 125 127
1:      nodes:  871890759       138924 knps
2:      nodes:  1257965016      163882 knps
3:      nodes:  45116064        147921 knps
4:      nodes:  281721009       160342 knps
5:      nodes:  988126927       152277 knps
6:      nodes:  938591610       155344 knps
7:      nodes:  808598060       159644 knps
8:      nodes:  2255285591      165343 knps
9:      nodes:  2719681285      160908 knps
10:     nodes:  286490531       153203 knps
11:     nodes:  1585542172      160936 knps
12:     nodes:  2285051692      155065 knps
13:     nodes:  183490910       160394 knps
14:     nodes:  1194475653      159199 knps
15:     nodes:  575648415       149480 knps
16:     nodes:  140110195       162352 knps
17:     nodes:  394245529       161841 knps
18:     nodes:  180578917       148015 knps
19:     nodes:  70444188        142599 knps
20:     nodes:  285230278       159524 knps
21:     nodes:  23366807        139088 knps
22:     nodes:  633262598       160849 knps
23:     nodes:  668759475       149210 knps
24:     nodes:  352861472       137460 knps
25:     nodes:  330373590       170471 knps
26:     nodes:  11280747        154530 knps
27:     nodes:  28608554        133684 knps
28:     nodes:  630739251       165071 knps
29:     nodes:  189345666       136024 knps
30:     nodes:  23231541        158037 knps
31:     nodes:  10492149        104921 knps
32:     nodes:  6425832         110790 knps
33:     nodes:  6739536         110484 knps
34:     nodes:  24009148        131197 knps
35:     nodes:  17176613        115279 knps
36:     nodes:  9533906         125446 knps
37:     nodes:  7785103         144168 knps
===========================
Total time (ms) : 129329
Nodes searched  : 20322276789
Nodes/second    : 157136270

[syzygy]

Does asmFish give higher nps with 128 threads?

[Zerbinati]

You should not use AVX2 on Zen 2 processors.

advisable modern?

[Modern Times]

You should not use AVX2 on Zen 2 processors.

advisable modern?

AVX2 is fine on Zen 2 isn't it, it is just BMI2 that is slow ? I don't have Zen 2 so can't comment from experience.

[Zerbinati]

The main problem is that only with stockfish I have no KN\s increase using SMT

[Zerbinati]

Does asmFish give higher nps with 128 threads?

yes also Dragon by Komodo
only Stockfish has no increment from 64 to 128
and really incomprehensible to me

[Joost Buijs]

You should not use AVX2 on Zen 2 processors.

advisable modern?

AVX2 is fine on Zen 2 isn't it, it is just BMI2 that is slow ? I don't have Zen 2 so can't comment from experience.

I have both Intel 10th gen and AMD Zen-2 and I can confirm that AVX2 speed on Zen2 matches Intel completely.
BMI2 on Zen-2 is unusable, that's why I'm waiting for the Zen-3 Threadripper, when it arrives I will ditch the 3970X.

[syzygy]

You should not use AVX2 on Zen 2 processors.

advisable modern?

AVX2 is fine on Zen 2 isn't it, it is just BMI2 that is slow ? I don't have Zen 2 so can't comment from experience.

Yes, I quickly realised I had mixed up things. But 1 minute of exposure was too long for it to go unnoticed