Re: thread-ready ABIs

[Ralf Baechle <ralf@oss.sgi.com>]

On Sat, Jan 19, 2002 at 01:35:38AM +0100, Kevin D. Kissell wrote:

> Thank you for posting this to linux-mips, since I'm not sure 
> that anyone at MIPS is on the GNU_libc_hacker list.
> 
> It would, in principle, be possible to save/restore k0
> or k1 (but not both) if no other clever solution can be found.  
> There are other VM OSes that manage to do so for MIPS, 
> for other outside-the-old-ABI reasons.  It does, of course,
> add some instructions and some memory traffic to the 
> low-level exception handling , and we would have to look 
> at whether we would want to make such a feature standard 
> or specific to a "thread-ready" kernel build.

Changing the kernel for the small number of threaded applications that
exists and taking a performance impact for the kernel itself and anything
that's using threads is an exquisite example for a bad tradeoff.

  Ralf