Re: [PATCH 4/6] Record how many zones can be safely skipped in the zonelist

From: Mel Gorman
Date: Tue Aug 21 2007 - 04:59:11 EST


On (17/08/07 14:03), Christoph Lameter didst pronounce:
> Is there any performance improvement because of this patch? It looks
> like processing got more expensive since an additional cacheline needs to
> be fetches to get the skip factor.
>

It's a small gain on a few machines. Where I thought it was more likely
to be a win is on x86-64 NUMA machines particularly if the zonelist
ordering was zone order as there would be potentially many nodes to
skip.

Kernbench didn't show up any regressions for the other machines but the
userspace portion of that workload is unlikely to notice the loss of a
cache line.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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