Re: Atomic migration chains, balancing fixes.

[Andrew Doran <ad%netbsd.org@localhost>]

On Tue, May 20, 2008 at 02:41:40PM +0100, Mindaugas Rasiukevicius wrote:

> > ... The cost of switching to the idle LWP to do a forced migration is
> > proably small when compared to the penalty that the migrating LWP will
> > suffer because of cache traffic and TLB refill.
> 
> Can you explain (at least shortly, please) your point about cache traffic and
> TLB refill, or how it suffer more than migration via idle LWP?

What I mean is: in comparison to the hardware penalty a thread would pay to
move its cache and VM footprint from one CPU to another, switching to the
local idle loop is likely to be cheap. So it's unlikely to be a large
component of the cost involved in migrating a thread.

Andrew