Am I 32-bit, or 64-bit?

[Michael ODonnell]

> I have seen that in 64-bit Linux, 32-bit processes tend to execute
> a bit faster.  I've seen a number of cases where 32-bit apps run
> faster than their 64-bit version, but I've also seen 64-bit apps
> run faster than their 32-bit versions.  

The 1g/3g memory split I mentioned allowed the kernel to "share"
the page tables with every process rather than using a dedicated
supervisor page table, obviating the page table switch (and the
associated TLB flushes, etc) that would otherwise be incurred
with every crossing of the User/Kernel boundary.  Since the x86_64
kernels do use a dedicated supervisor page table I have to assume
that some syscall-intensive 32bit apps do run a bit slower than
they would on an "equivalent" (whatever that means) x86 kernel.