HP OpenVMS Systems

Competing with the Null Job for CPU?

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The Question is:

 
Do you have any technical documents that supports the argument that a process
 can use up to 100% of the CPU if it is available and not in conflict with
 other scheduled processes?
 

The Answer is :

 
  The null job (the idle loop) effectively does this on all OpenVMS
  systems.  Many OpenVMS systems running the SETI software package
  are also configured to operate this way.
 
  The following DCL works quite nicely as an empirical test:
 
$ COPY SYS$INPUT: SYS$SYSDEVICE:[000000]X.MAR
  .psect  code,nowrt,exe
  .call_entry     preserve=<>,-
                  max_args=0,-
                  home_args=false,-
                  input=<>,-
                  output=<>,-
                  scratch=<>,-
                  label=<main>
  brb main
  .end main
$ MACRO SYS$SYSDEVICE:[000000]X.MAR/OBJECT=SYS$SYSDEVICE:[000000]X.OBJ
$ LINK SYS$SYSDEVICE:[000000]X.OBJ/EXEC=SYS$SYSDEVICE:[000000]X.EXE
$ RUN/DETACH/PRIORITY=0/PROCESS_NAME="Null Wannabe" SYS$SYSDEVICE:[000000]X
 

  

     

     
answer written or last revised on ( 22-MAY-2000 )
     
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