Re: The performance and behaviour of the anti-fragmentation related patches

Christoph Lameter
2007-03-03T03:15:44Z

On Fri, 2 Mar 2007, William Lee Irwin III wrote:

> On Fri, Mar 02, 2007 at 02:22:56PM -0800, Andrew Morton wrote:
> > Opterons seem to be particularly prone to lock starvation where a cacheline
> > gets captured in a single package for ever.
>
> AIUI that phenomenon is universal to NUMA. Maybe it's time we
> reexamined our locking algorithms in the light of fairness
> considerations.

This is a phenomenon that is usually addressed at the cache logic level.
Its a hardware maturation issue. A certain package should not be allowed
to hold onto a cacheline forever and other packages must have a mininum
time when they can operate on that cacheline.