On Thu, 6 Jul 2006, Benjamin Herrenschmidt wrote:

| On Thu, 2006-07-06 at 16:34 -0700, Bryan O'Sullivan wrote:
| > On Fri, 2006-07-07 at 08:37 +1000, Benjamin Herrenschmidt wrote:
| > 
| > > > +int ipath_unordered_wc(void)
| > > > +{
| > > > +	return 1;
| > > > +}
| > > 
| > > How is the above providing any kind of serialisation ?
| > 
| > It's not intended to; it tells the *caller* whether to do it.
| 
| Ah ok. What barrier do you use for that ?

on x86_64, the sfence instruction, on others, wmb(), in the kernel.  In user-land,
pretty much the same underlying assembly instructions.

Dave Olson
olson@unixfolk.com
http://www.unixfolk.com/dave