This was accidentally grouped into previous commit.
The destiny of this interface for internal use is still unclear (in context of
utilization in built-in data structures). The interface is enabled by default
on x86, as it is compatible with read-side prefetch* operations and
binary-compatible with 3DNow! extension. Older compilers will waste an
additional byte (they generate 3DNow! variant) on this, but older compilers
waste more on spillage if we encode instruction. Power support is coming soon.
Pointer packing is now disabled by default for x86_64 targets.
Jeffrey M. Birnbaum <jmbny.@...> told me that according to his
discussions with Intel engineers, Haswell will be bumping up
VMA bits to 56 bits from 48.
If you control the hardware that CK is deployed to and don't
envision a migration to 48-bits anytime soon, then you may
enable old behavior (resulting in significant memory savings
for some data structures, namely ck_ht) by passing the
--enable-pointer-packing flag to configure.
Samy Al Bahra
Samy Al Bahra