Re: multi-queue scheduler update

[Andi Kleen]

On Fri, Jan 19, 2001 at 02:35:02AM +0100, Andrea Arcangeli wrote:
> 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!
> 
> This is why the numbers with 2/4/8 threads in the runqueue are the most
> interesting ones 8)

With Arjan's patch to use prefetching for the runqueue scan the numbers
will be likely different [at least on cpus that can benefit from prefetching
like p2+ or athlon] 

-Andi