Author: Robert Hyatt
Date: 21:31:18 06/19/02
Go up one level in this thread
On June 19, 2002 at 17:43:08, Odd Gunnar Malin wrote: >On June 19, 2002 at 16:07:35, Heiner Marxen wrote: > >>On June 19, 2002 at 14:49:56, Dann Corbit wrote: >> >>>Some engines are far more effective at grabbing CPU cycles than others. For >>>instance, I do not like to run EPD tests on my machine for either Bringer or GLC >>>because they grab so much CPU, I cannot even move the mouse. The machine is >>>completely locked up for the duration of the test. >> >>Shame on the OS! >>Isn't the scheduler expected to prevent such locking? >> >>Cheers, >>Heiner > >There is nothing wrong with the os here. Win32 has 31 (*) levels for priorities >where a programer should stick to the predefined levels. If two engines run with >the same priority level they would get equal cpu usage. > >I have not done too many games with bringer but it seems that he force himself >to the front and therby get a boost if the user have decided that he will give a >boost for foreground programs. > >If I remember right so do glc run the search in another thread than the main >thread so playing a ponder on game on a gui that alter the priority is >pointless. > >Odd Gunnar >(*) From my memory so the number could be slightly different. Maybe. IE for ponder=off matches, there was a famous case where very early ChessMaster programs would use 3/4 of the CPU. They would use 100% while they were thinking (the opponent was not pondering) and then they would use 50% while the opponent was thinking, because the old ChessMaster would enter a tight loop "is there any input? no. Is there any input? no. " which gave it a 2:1 time advantage with ponder=off. Bad design. I assume it was fixed when ported to windows... But that could easily be repeated when someone writes their own GUI by just rolling forever through a message-loop waiting for input.
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