Re: [RFC] do_execve() perf improvement opportunity?

[Rik van Riel]

On Tue, 21 Jun 2005 cutaway@xxxxxxxxxxxxx wrote:

> I'll try to code this up and benchmark it and see if there's anything 
> measurable.  If there is, this sort of simple minded "cache the last 
> one" scheme might be applicable elsewhere too - pipes, maybe net 
> packets, etc. It looks like Slab already sort of "caches the last one" 
> on the different granularities, but it takes a bit more code to get to 
> the point where it finally figures out it can give you back a cached 
> one.

The thing is, that code may well be in cache already, while
a cache miss on a piece of data from another CPU is really
really expensive on SMP systems.

I suspect you may be able to get more performance gains
from inserting prefetches in strategic places than from
cutting out a bit of code.

-- 
The Theory of Escalating Commitment: "The cost of continuing mistakes is
borne by others, while the cost of admitting mistakes is borne by yourself."
  -- Joseph Stiglitz, Nobel Laureate in Economics
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