Syzygy TB extreme performance dropoff.

[rooklift]

I have all 5 man Syzygy rtbw and rtbz installed. The following is a quite shocking speed difference between using them and not (on Lc0 0.25.1, Windows, Cuda)...

uci
setoption name SyzygyPath value C:\Users\Owner\Documents\Misc\Chess\Syzygy
ucinewgame
position fen 8/5b2/8/2N5/6k1/8/8/KR6 w - - 0 1
go nodes 4000

info depth 1 seldepth 2 time 16 nodes 2 score cp 3947 nps 285 tbhits 2 pv a1b2 f7a2
info depth 2 seldepth 3 time 46 nodes 19 score cp 1479 nps 500 tbhits 2 pv a1b2 f7g6 b1g1
info depth 3 seldepth 4 time 68 nodes 31 score cp 2290 nps 516 tbhits 5 pv a1b2 f7g6 b1g1 g4f5
info depth 4 seldepth 5 time 703 nodes 429 score cp 1982 nps 617 tbhits 5 pv a1b2 g4h4 b2c3 h4g4 c3d4
info depth 4 seldepth 6 time 1186 nodes 732 score cp 2455 nps 621 tbhits 18 pv a1b2 g4h4 b2c3 h4g4 c3d4 f7a2
info depth 4 seldepth 7 time 1717 nodes 1062 score cp 2088 nps 621 tbhits 26 pv a1b2 g4g3 b2c3 f7h5 c3d4 g3h3
info depth 4 seldepth 8 time 2956 nodes 1830 score cp 2108 nps 620 tbhits 69 pv a1b2 f7g6 b1g1 g4f5 b2c3 g6h5 c3d4 h5f7
bestmove a1b2 ponder f7g6

(restarted Lc0)

uci
ucinewgame
position fen 8/5b2/8/2N5/6k1/8/8/KR6 w - - 0 1
go nodes 4000

info depth 1 seldepth 2 time 12 nodes 9 score cp 4439 nps 2250 tbhits 0 pv b1b4 g4f5
info depth 2 seldepth 3 time 15 nodes 124 score cp 2397 nps 17714 tbhits 0 pv b1b8 f7c4 a1b2
info depth 3 seldepth 4 time 23 nodes 393 score cp 3156 nps 28071 tbhits 0 pv b1b8 f7d5 a1b2 d5b7
info depth 3 seldepth 5 time 30 nodes 715 score cp 2954 nps 32500 tbhits 0 pv b1b8 g4f5 b8f8 f5f6 a1b2
info depth 4 seldepth 6 time 42 nodes 1303 score cp 2672 nps 38323 tbhits 0 pv a1b2 f7g6 b1d1 g6f5 b2c3
info depth 4 seldepth 7 time 65 nodes 2506 score cp 2600 nps 44750 tbhits 0 pv a1b2 f7a2 b2a2 g4f5 a2b3
info depth 4 seldepth 7 time 94 nodes 4136 score cp 2950 nps 48093 tbhits 0 pv b1b8 f7h5 b8a8 g4h4 a8h8 h4g4
bestmove b1b8 ponder f7h5

Discord user Tinker confirmed seeing the same thing. Lc0 0.24.1 is no better. Crem suggested I file this here.

[brianprichardson]

Looked into this a bit more.
With 4 pieces (no pawns) it is the same speed with and without TBs.

I also tried 6 pieces (removing the knight and adding pawns in front of each king).
Again, it was the same speed.

Not sure if this means anything, but still odd.

[mooskagh]

Do you have any antivirus installed?

[rooklift]

Just whatever comes with Windows 10.

[mooskagh]

Reproduced on Linux.
Have 700nps even on random backend with tablebases on SSD.

[rooklift]

Any chance we get a 0.25.2 for this? :)

[Tilps]

I'll note that I too had seen some strange performance behavior with play during TB positions - sometimes with 6 pieces still on board with TB on SSD. I hadn't managed to track it down as I didn't have a repro scenario as the games went past too fast :P. Thanks for tracking this down.