cgd@broadcom.com wrote:

> At Thu, 4 Jul 2002 22:08:08 +0000 (UTC), "Gregory McGarry" wrote:
> > I will add machdep.llsc sysctl for model-specific library.
> > Unfortunately, static binaries linked against libpthread currently
> > don't work on mips.  Something wrong with _init() not being
> > invoked.  But you do mention another issue to add to the list.
> 
> I'd say this is the wrong way to go about this.
> 
> the default should be something which can work on MP systems, etc.,
> without any special libraries.  The special libraries should be
> considered an optimization, _not_ necessary for correct operation
> under any circumstances.  (RAS can work for certain kernel purposes on
> MP systems, but that's it, right?)
> 
> Further, I'd _like_ to think that the commmon case going forward is
> "cpus which have LL/SC," so that is what should be catered to.
> Certainly, all of the new MIPS32/MIPS64 CPUs which show up will have
> them.
> 
> That said, I believe the default should be ll/sc (emulated by the
> kernel if not present in the HW), with a lib which uses RAS to
> optimize things on older HW.
> 
> For static bins, given the huge performance difference, it's probably
> "the right thing" to have function pointer(s), set on initial use, to
> select the proper locking primitives unless compiling w/ flags that
> narrow things down to a well-known CPU model.  Yeah, it's a bit of
> extra overhead, but it's not that much in the "high-performance" case,
> and it's a huge huge win in the "low-perforance" case.

OK.  I'll do it that way.

	-- Gregory McGarry <g.mcgarry@ieee.org>