merge vm_version_x86_{32,64}.hpp

Vladimir Kozlov Vladimir.Kozlov at Sun.COM
Mon Feb 23 05:39:42 PST 2009

Christian Thalinger wrote:
> On Mon, 2009-02-23 at 07:29 -0500, Paul Hohensee wrote:
>> Imo, the #ifdef's are ok in this case because they're quite limited.
>> Vladimir set prefetch distances based on experiment.  The difference
>> between 320 and 384 is a single cache line.  It seems to me that 32
>> and 64-bit would be the same because it's the same hardware, except
>> that it may be that 64-bit code is faster than 32-bit code, thus would
>> require a slightly greater prefetch distance.

No, it is because different average allocation object's size (different oop size).

>> 32-bit doesn't use the Prefetchxxx switches because there's no common
>> prefetch instruction for 32-bit that can be used in C++ code.  #ifdef is
>> ok here.

That is correct.

> Paul, thank you for the explanation.  Last question: should I use the
> _LP64 or AMD64 define?
> -- Christian


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