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HalTranslateBusAddress/MmMapIoSpace memory slow?

OSR_Community_UserOSR_Community_User Member Posts: 110,217
Hello all,

An interesting result...I have set aside a large chunk of memory using
/MAXMEM. I am using HalTranslateBusAdress and MmMapIoSpace to address the
memory. The RtlCopyMemory() is about 4 times slower than copying memory
from within NT normal memory space! It does not seem to matter is
MmMapIoSpaces' Cache is TRUE or FALSE. The test uses a single RAM DIMM
for NT and the extra memory, so it has to do with the way the intel's
cache lines are being tugged around, but is there a solution?

TIA,
John
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