Re: [rfc 37/45] x86_64: Support for fast per cpu operations

H. Peter Anvin
2007-11-20T02:13:35Z

Christoph Lameter wrote:
> Support fast cpu ops in x86_64 by providing a series of functions that
> generate the proper instructions. Define CONFIG_FAST_CPU_OPS so that core code
> can exploit the availability of fast per cpu operations.
>
> Signed-off-by: Christoph Lameter <clameter@sgi.com>

There was, at some point, discussion about using the gcc TLS mechanism,
which should permit even better code to be generated. Unfortunately, it
would require gcc to be able to reference %gs instead of %fs (and vice
versa for i386), which I don't think is available in anything except
maybe the most cutting-edge version of gcc.

However, if we're doing a masssive revampt it would be good to get an
idea of how to migrate to that model eventually, or why it doesn't make
sense at all.

-hpa