Re: 2.6.19-rc5-mm1 progression

[Nick Piggin]

Peter Zijlstra wrote:
> On Mon, 2006-12-04 at 21:32 -0600, Larry Finger wrote:

> > There are at least two patches in 2.6.19-rc5-mm2 that make my system much more responsive for 
> > interactive jobs. The one that has the majority of the effect is:
> >
> > radix-tree-rcu-lockless-readside.patch
> >
> > I have not been able to isolate the second patch, which has the lesser effect. All I can say is that 
> > it occurred before the above patch in patches/series. This patch was tested against 2.6.19 and fixed 
> > most of the problem on that version.
>
>
> Curious...
>
> This patch introduces the direct pointer optimisation for single element
> radix trees and makes the radix tree safe to read in a lock-less manner
> which is not used -yet-. The only difference that that should have is
> that the elements are freed using rcu callback instead of directly.
>
> /me puzzled how this has a large effect on interactivity.
>
> Nick?

I have already got the direct data optimisation upstream. It might be
possible that it is some interaction with the extra rcu callbacks going
off... I don't know :\

--
SUSE Labs, Novell Inc.
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