Re: CVS commit: src/sys/kern

[Martin Husemann <martin%duskware.de@localhost>]

On Thu, Jun 02, 2011 at 09:21:11PM +0100, David Laight wrote:
> Passing 'l' is a register rename (or copy) so is almost zero cost.
> 
> Recovering curlwp may involve a function call, and is, at best, a real
> memory access of global data (possibly via an asm statement) that will
> be slow and multiple accesses might need caching in a local anyway.

I wonder on what archs we would be able to do the MIPS curlwp optimization
(place curlwp in a reserved register).

Sparc64 and sparc will likely follow this in the near future (needs some audit
and will do some benchmarks first; it closely resembles TLS for userland).

What's the cost on other archs and what optimizations are possible?

Martin