2.4/2.6/ppc/powerpc/8245/8347e

Marc Leeman marc.leeman at gmail.com
Tue Jul 10 17:55:29 EST 2007


> > I was expecting a lower DMM performance but wasn't expecting such a
> > drain on kernel/network load.
> 
> OK, to be clear: you seem to be saying that using the SLOB instead
> of the SLAB allocator results in such terrible memory fragmentation
> that network performance is degraded by large factors (2x or 5x or
> something like that, if I remember your earlier emails). Is that right?

Yep, I thought I would at least post my findings after hurracing the
list with my posts.

Well, I don't really know if it is the fragmentation that comes into
play, or if it is simply the implementation of the slob allocator that
much more inefficient in allocating free blocks of memory; but that's
about right.

> I thought I heard about some memory-defrag patches being posted.  
> What happens if these are used together with SLOB? Does one regain the
> lost performance? Perhaps maybe one gets even better performance?

In the ChangeLog of the 2.6.22, I saw something about a slub allocator
that I want to test; I'll give your suggestion a go too, though I would
not expect significant improvements: I suspect it's the slob
implementation that is slower.

But I had a small problem with my flash not being detected anymore when
quickly booting the 2.6.22, I'll look into it today, there was a note in
the ChangeLog for powerpc about this IIRC.

-- 
  greetz, marc
Better wed than dead.
	Crichton - Look at the Princess - A Kiss is Just a Kiss
chiana 2.6.18-4-ixp4xx #1 Tue Mar 27 18:01:56 BST 2007 GNU/Linux
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