[SOLVED] TProcess — ppRealTime priority does not work
lazarus / 34-Windows

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flowCRANE · 2021-01-21 17:44

I have a strange problem. My program uses one TProcess instance to run
an external program (here: the FCEUX emulator). In addition to
specifying the application path and the ROM file to open in the
emulator, it also sets the priority to the highest possible, i.e.
ppRealTime (it is required):

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
]"]>Blockedlator.InitProcess();begin  FProcess :=
TProcess.Create(nil);   {$IFDEF REGION_PAL}  FProcess.Executable :=
'emulator\pal\fceux64.exe'; 
FProcess.Parameters.Add('emulator\pal\games\Tetris (Europe).nes'); 
{$ELSE}  FProcess.Executable := 'emulator\ntsc\fceux64.exe'; 
FProcess.Parameters.Add('emulator\ntsc\games\Tetris (USA).nes'); 
{$ENDIF}   FProcess.Priority := ppRealTime;  FProcess.Execute();end;
The emulator boots up correctly, but its process priority is set to
High instead of Realtime (see attachment). My program (the one running
the emulator) works with basic permissions, so does the emulator.
System info and Lazarus version in signature.

Does anyone know why this is happening and how to fix it?

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ASerge · 2021-01-21 18:25

By default, the SeIncreaseBasePriorityPrivilege privilege, which is
required to set the realtime priority for processes, is disabled even
for admins. It must be requested explicitly.

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flowCRANE · 2021-01-23 12:05

Ok, thank you very much for the information. I changed the execution
level from asInvoker to requireAdministrator in the project settings
window, and it now works fine. But the problem is that now I'm not
able to run my application in debug mode (using IDE) — every time the
debugger just crash. The solution is to run Lazarus as administrator,
so I have to remember this.

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ASBzone · 2021-01-26 04:02

You should be very careful with the RealTime priority.

https://devblogs.microsoft.com/oldnewthing/20100610-00/?p=13753