UCI protocol and engine strength

[Kempelen]

Hi
While doing UCI implementation I have noted my engine has notable ELO loss. I have lost a lot of time trying to figure what could cause this situation, but the implementation seems good and I dont seen any performance bottleneck. Talking to Pedro Castro some time ago he noted similar thing while testing Danasah. Has anybody noted something similar? any ideas?
Regards
Fermín

[brtzsnr]

Hi Fermin!

Given that IO code does very little work, I find this surprising so we need more information to track down the regression.

How did you test the regression? Did you play enough tests? What's the Elo drop? A typical no-regression tests needs about 30k-40k for my engine.

As for sources of Elo loss:
- are you clearing the hash every position?
- does cpu profile shows anything unusual in the new UCI code?


Edit: For Zurichess I remember that printing the PV lines were very time consuming showing something 3-4 Elo drop. Newer versions of the Go compilers fixed that, fortunately.

[mjlef]

Hi
While doing UCI implementation I have noted my engine has notable ELO loss. I have lost a lot of time trying to figure what could cause this situation, but the implementation seems good and I dont seen any performance bottleneck. Talking to Pedro Castro some time ago he noted similar thing while testing Danasah. Has anybody noted something similar? any ideas?
Regards
Fermín

One possibility is time it takes to send information to and from the engine. Most programs do periodic polling or run the I/O in another thread. In Komodo, we have an option to suppress much of the engine output for the first X plies. It just puts out the best move and a few other things, and not each current move notification and long PVs.

[matthewlai]

Hi
While doing UCI implementation I have noted my engine has notable ELO loss. I have lost a lot of time trying to figure what could cause this situation, but the implementation seems good and I dont seen any performance bottleneck. Talking to Pedro Castro some time ago he noted similar thing while testing Danasah. Has anybody noted something similar? any ideas?
Regards
Fermín

Time management bug would be my prime suspect. Does it use reasonable amount of time?

[Ferdy]

Hi
While doing UCI implementation I have noted my engine has notable ELO loss. I have lost a lot of time trying to figure what could cause this situation, but the implementation seems good and I dont seen any performance bottleneck. Talking to Pedro Castro some time ago he noted similar thing while testing Danasah. Has anybody noted something similar? any ideas?
Regards
Fermín

position startpos moves e2e4 e7e5 ... <last move> till move 80 say.

When playing games (even in analysis mode), don't verify the legality of those moves. Verify only the last move sent by the gui. Save those moves incrementally in history, the first time you receive e2e4 save e2e4, you receive e2e4 e5e7, save e7e5 only because e2e4 was already in your move history. When you receive ucinewgame, clear your history. If last move is illegal, setup everything from start.

[whereagles]

Possibly related to this, I noticed a very considerable slow-down from running Stockfish 7 under the ChessX interface on Mac. Using the SF7 Mac app, I get to much higher depths for the same time span.

Perhaps ChessX invokes SF7 from a clear cache whereas the Mac app keeps the cache? (Cache size is the same for both.)