Re: [RFC][PATCH] _UC_TLSBASE for all ports

[Eduardo Horvath <eeh%NetBSD.org@localhost>]

On Sat, 11 Aug 2012, Matt Thomas wrote:

> On Aug 11, 2012, at 10:35 AM, Thor Lancelot Simon wrote:
> 
> > On Sat, Aug 11, 2012 at 06:45:12AM +0000, Christos Zoulas wrote:
> >> 
> >> It is a slippery slope, but I think in this case it is wise to bend.
> >> If we cannot reach agreement here, consult core.
> > 
> > I see no point bending NetBSD into knots in this case if the resulting
> > performance is as bad as Joerg claims it will be.  Is it actually the
> > case that our *context() functions are almost as heavy as a full
> > kernel-level thread switch?
> 
> I'm wondering if we need a new makecontext which can allocate a new
> private thread-local area.  We can set the stack via uc_stack but
> there isn't a way to allocate a new thread-local area.
> 

I think this whole thing needs a careful redesign.  IMHO the reason we 
never got scheduler activations stable across all architectures is that 
the semantics of the *context() routines were never properly specified.  

If I knew what those routines were supposed to do I might have been able 
to fix them.  But as it was implementation defined functionality....

Eduardo