Re: [v2.6.26] what's brewing in x86.git for v2.6.26
From: Ingo Molnar
Date: Fri Apr 18 2008 - 04:39:01 EST
* Alexander van Heukelum <heukelum@xxxxxxxxxxx> wrote:
> My conclusion would be: the speed of the generic bitmap implementation
> is either better than or at least comparable to the current private
> implementations in i386/x86_64. The generic version is out-of-line,
> while the private implementation of i386 was inlined: this causes a
> regression for very small bitmaps. However, if the bitmap size is a
> constant and fits a long integer, the updated generic code should
> inline an optimized version, like x86_64 currently does it.
>
> I think the change is a good one.
quite so. Your change was promising from the get go and the latest
iteration was definitely a good one and is very much mergable. That it
also helps improve other architectures is the icing on the cake.
Andi will have to prove his points by coming up with competing benchmark
results - you certainly did your fair share to back up your change with
numbers. (and Andi, if/when you do so, please Cc: Alexander too in the
future. Dont you want him to be able to reply to your complaints ASAP?)
I dont really understand the negativism that comes from Andi - he was
very much aware of the various iterations and benchmarks you did when
developing this rather cool feature: he participated in those threads
and was Cc:-ed as well. The "100% bogus benchmark with the most
unrealistic input data set one can imagine" remark from Andi with no Cc:
was a nasty and unprovoked hit below the waistline.
Ingo
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