>Does anyone know how to change the TLB size?

Once you wade through all of the smart-ass replies
let me mention the following.

While the "size" of the TLB measured in number of
TLB-entries is cast in silicon, nearly all modern
CPU architectures (including the amd64/x86_64) have
scheme for increasing the effective capacity of the
TLB measured as the total amount of virtual address
space that can be mapped.  This is because modern
TLB designs allow TLB entries to map varying size
windows of virtual address space.

The problem here is one of OS software.  The size
of the window mapped by a TLB entry is intimately
related to the software's page size.  The Linux
kernel is just now beginning to add support for page
sizes larger than 4K.  This is turn ripples back
into file system design, free space management, etc.
Think pages sizes of 64KB or 1MB.  IBM has announced
PPC support for 1GB TLB mappings!  Such architectural
features are designed to support VERY large systems
with lots of memory working with VERY large datasets.

Anyway, it is going to be a while before such support
is available from a conservative release like Gentoo.  

/john


-- 
gentoo-amd64@g.o mailing list