Search found 284 matches
- Mon Dec 28, 2020 12:22 am
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Asynchronous tablebase lookups
- Replies: 9
- Views: 2175
Re: Asynchronous tablebase lookups
An effect I hadn't thought of: It seems that synchronous tablebase lookups also make the “stop” command a bit slower, since there's no way to abort an mmap-induced I/O operation. Of course, with an SSD we're only talking milliseconds, but on rotating media with many threads hammering, you could get ...
- Wed Dec 23, 2020 12:51 am
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Advent of Code 2020
- Replies: 5
- Views: 1522
Re: Advent of Code 2020
Isn't day 13 part 2 just the Chinese remainder theorem? It can be solved by hand if you wish. Or you can use any of the available online CRT calculators, which will find the answer in a split second.
- Tue Dec 22, 2020 11:43 pm
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Position Causes Stockfish and Komodo To Crash
- Replies: 135
- Views: 18635
- Tue Dec 22, 2020 1:17 pm
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Position Causes Stockfish and Komodo To Crash
- Replies: 135
- Views: 18635
Re: Position Causes Stockfish and Komodo To Crash
This just makes me even more convinced you'll need to just brute-force the possible unmoves to see if there are any. 

- Mon Dec 21, 2020 5:34 pm
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Advent of Code 2020
- Replies: 5
- Views: 1522
Re: Advent of Code 2020
If you want to compete for the top spots, you'll either need to live in a “good” timezone or get up really early in the morning. Not worth it. 

- Sun Dec 20, 2020 3:22 pm
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Asynchronous tablebase lookups
- Replies: 9
- Views: 2175
Re: Asynchronous tablebase lookups
I guess it's time for me to look into io_uring ;-) It's surprisingly comfortable! (But do use liburing, not the syscalls directly.) So one approach would be to let the TB probe fail if it the data is not immediately available. This is what the Gaviota probing code can do as well ("soft probes"). Bu...
- Sun Dec 20, 2020 1:24 pm
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Asynchronous tablebase lookups
- Replies: 9
- Views: 2175
Re: Asynchronous tablebase lookups
Not sure about that. The page faults are already happening now anyway. But it may be tricky to roll back the TB probe efficiently. But there's no good reason why they'd need to happen? io_uring will give you I/O without ever transitioning into kernel space. If you can do 1M TB lookups per second, i...
- Sun Dec 20, 2020 1:13 pm
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Position Causes Stockfish and Komodo To Crash
- Replies: 135
- Views: 18635
Re: Position Causes Stockfish and Komodo To Crash
Yeah, I noticed so myself. They didn't appear in preview when I wrote the post, however…
- Sun Dec 20, 2020 11:42 am
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Asynchronous tablebase lookups
- Replies: 9
- Views: 2175
Re: Asynchronous tablebase lookups
TBH I think you have to just abandon mmap to get this kind of performance going. You don't want to be roundtripping through the kernel on every I/O.
- Sun Dec 20, 2020 11:12 am
- Forum: Computer Chess Club: Programming and Technical Discussions
- Topic: Position Causes Stockfish and Komodo To Crash
- Replies: 135
- Views: 18635
Re: Position Causes Stockfish and Komodo To Crash
It seems you don't even need a double-check to make an unreachable position. For instance, how did this happen? [D]k1R5/2p4K/8/pp1ppppp/rnbq1bnr/8/PPPPPPPP/RNBQ1BN1 OTOH, I guess it should be fairly cheap to backwards-generate all moves, captures and promotions and see if any of them are without che...