Re: The performance and behaviour of the anti-fragmentation relatedpatches
From: Martin J. Bligh
Date: Sat Mar 03 2007 - 12:20:07 EST
Christoph Lameter wrote:
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.
That'd be nice. Unfortunately we're stuck in the real world with
real hardware, and the situation is likely to remain thus for
quite some time ...
M.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/