On Thu, Aug 18, 2011 at 12:22 PM, Alexander Kjeldaas <alexander.kjeld...@gmail.com> wrote: > The Nehalem micro-architecture has made unaligned loads very cheap, as long > as they do not cross a cache line boundary. > I am thinking that this makes it possible for ghc to use 40-bit pointers, > and generally use "packed" structure layout. This again should improve > performance by increasing the effective CPU cache size. > Even given a packed structure layout, the memory allocator could be improved > to ensure that no object field will cross a cache line by moving the object > a few bytes in either direction. > Comments? How hard-coded is the ghc object layout?
I believe there are lots of assumptions about the alignment of heap objects i.e. we use word sized loads which would fail on some architectures if allocated memory wasn't word aligned. -- Johan _______________________________________________ Cvs-ghc mailing list Cvs-ghc@haskell.org http://www.haskell.org/mailman/listinfo/cvs-ghc
