Re: multi-queue scheduler update

[Andi Kleen]

On Thu, Jan 18, 2001 at 08:00:16PM -0500, Mark Hahn wrote:
> > >                            microseconds/yield
> > > # threads      2.2.16-22           2.4        2.4-multi-queue
> > > ------------   ---------         --------     ---------------
> > > 16               18.740            4.603         1.455
> > 
> > I remeber the O(1) scheduler from Davide Libenzi was beating the mainline O(N)
> 
> isn't the normal case (as in "The Right Case to optimize") 
> where there are close to zero runnable tasks?  what realistic/sane
> scenarios have very large numbers of spinning threads?  all server
> situations I can think of do not.  not volanomark -loopback, surely!

I think the main point of Mike's patch is decreasing locking and cache line
bouncing overhead of multi cpu scheduling, not optimizing lots of runnable tasks.

-Andi