TCEC resurrection - need to decide between ponder ON or OFF

[hgm]

You proposed "engine A cores 1, 3 and 5, and of engine B to cores 2, 4, 6" and in this proposition engine A gets all the logical cores (1,3,5 are all logical cores) while B all the physical ones (2,4,6).

You have a misconception of how HT works. With HT on there are no physical cores to get, and all a process could ever get is one or more logical cores. One physical core is multiplexed to emulate two fully equivalent logical cores. The odd slots in the re-order buffer will contain the instructions of one logical core, the even slots those of the other.

Now the question is: do you want to manually adjust affinities every time a match is started?

No, you would want the GUI (or Polyglot) to do that.

[Martin Thoresen]

In a 4 CPU cores 0,2,4,6 are the physical ones, 1,3,5,7 the logical. If you want to give only 1 real physical + 2 threads then you must give something like 0,1,3 to one and 2,5,7 to the other. But I think it's better 2 physical + 1 thread.

Thanks for this information.

As far as I know, I can only select priority in ChessGUI, not affinity... so this idea might not work.

edit: If what HG Muller is saying is correct then it doesn't matter; no cores are pre-defined as logical or physical when running HT.

[Lavir]

You have a misconception of how HT works. With HT on there are no physical cores to get, and all a process could ever get is one or more logical cores. One physical core is multiplexed to emulate two fully equivalent logical cores. The odd slots in the re-order buffer will contain the instructions of one logical core, the even slots those of the other.

I don't have a "misconception" about anything. If you use Windows and set affinities manually (or via the "set affinity" hex mask) the 0,2,4,6 (on a 4 CPU PC) are the physical cores, while 1,3,5,7 are the logical cores.

There ARE the physical cores, in HT: 'Hyper-threading works by duplicating certain sections of the processor—those that store the architectural state—but not duplicating the main execution resources. This allows a hyper-threading processor to appear as the usual "physical" processor and an extra "logical" processor to the host operating system' and for the system one is the physical, and the other is the logical.

[Lavir]

Thanks for this information.

As far as I know, I can only select priority in ChessGUI, not affinity... so this idea might not work.

edit: If what HG Muller is saying is correct then it doesn't matter; no cores are pre-defined as logical or physical when running HT.

You have do do it manually (in every case: there are programs that can automate the setting of affinity, but in this case they will not work because how can you anticipate which engine will get one or the other sets?)

What Muller said is wrong. For the OS one is a physical core, the other is the logical one, and it will behave differently in the two cases. With the physical it will behave exactly as without having HT, with the logical it will duplicate the resources.

[hgm]

As far as I know, I can only select priority in ChessGUI, not affinity... so this idea might not work.

edit: If what HG Muller is saying is correct then it doesn't matter; no cores are pre-defined as logical or physical when running HT.

You can run the engines through Polyglot, which does support an "Affinity" option.

[Lavir]

You can run the engines through Polyglot, which does support an "Affinity" option.

I know it, but how can you do it automatically?

How can you anticipate that all engines with automatic setted affinities will work fine against other sets?

For example, you give 4 engines 0,1,2 and the other 4 4,5,6; what it happens when two of the 2nd group meet each other? How can you give an automatic rule that encompass every scenario? You cannot. You have to switch manually to be sure that everything is fine.

[hgm]

I would tell the GUI it should run the first engine with affinity mask 0x155, and the second engine with 0x2AA. (Something like -firstOptions "Polyglot Affinity=155" -secondOptions "Polyglot Affinity=2AA" (or whatever the syntax for this option is) as fixed GUI options, so not installed with any engine.)

I must admit that I have never used this option myself, as I never use Polyglot.

[Lavir]

I would tell the GUI it should run the first engine with affinity mask 0x155, and the second engine with 0x2AA. (Something like -firstOptions "Polyglot Affinity=155" -secondOptions "Polyglot Affinity=2AA" (or whatever the syntax for this option is) as fixed GUI options, so not installed with any engine.)

I must admit that I have never used this option myself, as I never use Polyglot.

Oh well, if that works then it's wonderful. All the programs I knew that automated affinities always acted through the program itself (and inherited on the children) but if with Polyglot it's possible to set affinities indipendently from the exe then it's perfect.

Now it all depends if Martin wants to do something like that (with the uncertainties tied to it, I guess he should test the thing a little) or he prefers more "usual" ways of running the tournament.

[IGarcia]

The purpose of TCEC was not about testing engines and statistic accuracy, it was about chess entertainment and competition. Games have been played one at a time so the spectators can follow, comment, chat etc. It had been a lot of fun.

I wish him the best with that, because I've found that not many spectators tend to chat with each other when they've been watching the live broadcasts I've been running. Fingers crossed.

Hehehe if you see the chat logs in your toms server, you will see some "Ignacio Garcia" login and saying hello in chat to never get a response form several "anonymous" And never see you on chat. After some times you give up, and then, on other reconnection, you never bother to write because you already know nobody will answer.

Most probably is because usesr not looking at chat, few peolple, etc. And Most time you enjoy watching and concentrating in the game, not the chat. In Chessbomb where there is a lot of poeple watching (several games, tournaments, etc) is a different story.

Other Big issue is the time when games are played, can be 3pm in Austalia/NewZeland and ~2am in new york/brasil/argentina/chile and 5am in Madrid.. so Graham is only chatting with the Kangoos

[michiguel]

...and the choices are:

1: 3 cores ponder OFF
2: 1 core ponder ON

The computer that is going to be used is an Intel Core i7 3770k @ 4400 MHz.

With ponder OFF the engines will search faster/deeper with 3 cores as opposed to just 1.

On the other hand, with ponder ON it doesn't matter if the engine is SMP capable or not as all engines have equal terms.

What do you prefer?

[MODERATION]

A new poll has been open.
http://www.talkchess.com/forum/viewtopic.php?t=46734

We are not locking this thread because there is still some exchange going on, but let's try to wrap it up here and move to the other thread, if anybody wants to add a new comment that could easily fit in the new thread.

Thanks,
Miguel