New REBEL's

[Hai]

How to install Rebel Extreme on macOS?

[Jouni]

Rebel still using max 1 threads? Why there is that uci parameter?

[Rebel]

Rebel still using max 1 threads? Why there is that uci parameter?

Activate the number of threads in the GUI you are using.

[Jouni]

Like Pohl writes in ProDeo forum: Multithreading broken in Rebel. In Fritz GUI it always uses only 1 core and has 800 knps speed in opening position. I wonder how CCRL has succeeded in testing Rebel 16.3 64-bit 8CPU!?

[Steve Maughan]

Like Pohl writes in ProDeo forum: Multithreading broken in Rebel. In Fritz GUI it always uses only 1 core and has 800 knps speed in opening position. I wonder how CCRL has succeeded in testing Rebel 16.3 64-bit 8CPU!?

I tested Rebel Extreme in the Shredder GUI on Windows. Indeed, there seems to be a problem. It crashes when I set the threads parameter to 4.

— Steve

[pohl4711]

You have to start Rebel with "poweruser" in the command-line. Then Rebel can use as many threads as the number of physical cores on the PC is, sadly not more. But this works.
When doing this without "poweruser", Rebel still runs in cutechess-cli or cutechess GUI, but the CPU load is only half of the load, compared with poweruser in command-line.
If CCRL tested Rebel with 8 cores, they have to set poweruser in the command-line. Otherwise they loose 50% of speed and the results are just bogus.
Very strange, overall.

[chrisw]

You have to start Rebel with "poweruser" in the command-line. Then Rebel can use as many threads as the number of physical cores on the PC is, sadly not more. But this works.
When doing this without "poweruser", Rebel still runs in cutechess-cli or cutechess GUI, but the CPU load is only half of the load, compared with poweruser in command-line.
If CCRL tested Rebel with 8 cores, they have to set poweruser in the command-line. Otherwise they loose 50% of speed and the results are just bogus.
Very strange, overall.

It's legacy code of mine, designed to stop crazy endusers from setting 128 cores and then complaining the thing crashed. There's always something to complain about, however one tries to work around it.

[Eelco de Groot]

Like Pohl writes in ProDeo forum: Multithreading broken in Rebel. In Fritz GUI it always uses only 1 core and has 800 knps speed in opening position. I wonder how CCRL has succeeded in testing Rebel 16.3 64-bit 8CPU!?

I tested Rebel Extreme in the Shredder GUI on Windows. Indeed, there seems to be a problem. It crashes when I set the threads parameter to 4.

— Steve

I don'think I have tried the 'poweruser' option anywhere yet, if that makes a difference. On my i5 old machine, I can make a Rebel Extreme with two threads. I think I have to navigate to all of the places where Shredder stores some stuff in Windows, there are a lot of those places. Crazy stuff, but using the search function I finally have all the .eng files that you can edit. Is the only way I think to do it unless you can use the command line somehow. Now I can make a SMP version:

My Rebel-EXTREME SMP.eng:

[ENGINE]
Name=Rebel-EXTREME SMP
Author=Ed Schroder and Chris Whittington (C) 2
Filename=C:\Users\Gebruiker\Downloads\REBEL-EXTREME\REBEL-EXTREME.exe
[OPTIONS]
RelaxThreadLimit=1
Threads=4

RelaxThreadLimit=1 was edited with NOTEPAD++ into the .eng file and saved, then Shredder restarted, now at least you should have two threads, on a more powerful CPU version with hyperthreading you may get 4 threads ( ). (Dann was able to get 62 threads I think;

Dann's thread way back on Pro Deo, about his request: https://prodeo.actieforum.com/t1112-pro ... readripper
See also some posts where Chris Whittington asks for people to check 'mem' command to see how much threads CSTal thinks it can safely use:
forum3/viewtopic.php?t=81573&start=110
)

My Shredder on old Dell i5:

CPU0: GenuineIntel Intel64 Family 6 Model 60 Stepping 3 3093 MHz
CPU1: GenuineIntel Intel64 Family 6 Model 60 Stepping 3 3093 MHz
CPU2: GenuineIntel Intel64 Family 6 Model 60 Stepping 3 3093 MHz
CPU3: GenuineIntel Intel64 Family 6 Model 60 Stepping 3 3093 MHz
GUI: Eindspeldatabanken met 0 stukken gevonden! [Buffer: 1 MB + intern 0.00 MB]
GUI: Shredderbases met 0 stukken gevonden (0 MB)
Rebel-EXTREME
(C) Ed Schroder, Chris Whittington 2003-2024
Code Base : Chris Whittington
NNUE development : Ed Schroder
==============================
set Hash to 1024MB
Hash table set to 1024 MB
set Ponder to value true
set RelaxThreadLimit to value true
Instability Warning - at your own risk
set Threads to 4
limiting Threads to 2 cores
Engine: Rebel-EXTREME SMP (1024 MB)
gemaakt door Ed Schroder and Chris Whittington (C) 2

[RubiChess]

It's legacy code of mine, designed to stop crazy endusers from setting 128 cores and then complaining the thing crashed. There's always something to complain about, however one tries to work around it.

If the engine crashes when using more threads than cores available then there's a bug you should fix.

[pohl4711]

It's legacy code of mine, designed to stop crazy endusers from setting 128 cores and then complaining the thing crashed. There's always something to complain about, however one tries to work around it.

If the engine crashes when using more threads than cores available then there's a bug you should fix.

Exactly. I dont know any other engine in the top30 or so, wich has such a bad multithreading. This is not only bad for the users, but for the engine Rebel itself, too: Until the multithreading is as bad as it is, Rebel can never participate in TCEC or in the engine-tournaments on chesscom. What a waste of potential of this great engine. Sad.