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Par2: Set Processor Affinity
2007-03-02 -- Bjorn Holm
 
I have added this code to my programs: MAP Module('winapi') SetProcessAffinityMask(UNSIGNED,LONG),LONG,PASCAL,RAW GetCurrentProcess(),LONG,PASCAL,RAW GetSystemInfo(LONG),PASCAL,RAW End End SYSTEM_INFO GROUP,TYPE dwOemId LONG dwPageSize LONG pMinimumApplicationAddress ULONG lpMaximumApplicationAddress ULONG dwActiveProcessorMask LONG dwNumberOfProcessors LONG dwProcessorType LONG dwAllocationGranularity LONG dwReserved LONG wProcessorLevel USHORT wProcessorRevision USHORT wProcessorArchitecture USHORT END SystemInfo LIKE(SYSTEM_INFO),AUTO Loc:ProcCount Long Loc:ProcNo Long GetSystemInfo(ADDRESS(SystemInfo)) Loc:ProcCount = SystemInfo.dwNumberOfProcessors If Loc:ProcCount > 1 Then Loc:ProcNo = Random(1, Loc:ProcCount) A# = SetProcessAffinityMask(GetCurrentProcess(),Loc:ProcNo) End takes care of multiprocessor systems for me. : ) Carl Barnes notes: Your code is wrong if there are more then 2 processores. It's a "bit-mask" and not processor number. So if there are 4 processors and you pick processor 3 you are using a mask of 3 which is 011b and you are assigning your EXE to processors 1 and 2. Or if you pick 4 which is 0100b you are asigning processor 3. You'll never assign to processor 4 since that mask value is 8. Your code should be (untested) BSHIFT long Loc:ProcNo = Random(1, Loc:ProcCount) CPUBM = BSHIFT(1,Loc:ProcNo-1) !or 2^(Loc:ProcNo-1) A# = SetProcessAffinityMask(GetCurrentProcess(),CPUBM) If your going to add runtime affinity code to the EXE that way IMO the right way is to use GetProcessorAffinity() and not GetSystemInfo(). Then select a processor from the affinity mask your Process has been assigned, not the system mask. Assigning processor affinity at runtime from dwNumberOfProcessors will ignore an affinity assigned in the EXE header (by the compiler or ImageCfg.exe) or by the Windows loader that already is a subset of the maximum processors in the system.


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