On Tuesday 08 December 2009 17:15:36 Kevin Grittner wrote:
> Andres Freund <andres@anarazel.de> wrote:
> > Could you show your testcase?
Will hopefully look into this later.
> > I dont see why it could get slower?
> I don't either. The best I can tell, following the pointer from
> orig to any of its elements seems to be way more expensive than I
> would ever have guessed. The only thing that seemed to improve the
> speed was minimizing that by using a local variable to capture any
> element referenced more than once. (Although, there is overlap
> between the timings for the original patch and the one which seemed
> a slight improvement; I would need to do more testing to really rule
> out noise and have complete confidence that my changes actually are
> an improvement on the original patch.)
>
> Perhaps it is some quirk of using 32 bit pointers on the 64 bit AMD
> CPU? (I'm looking forward to testing this today on a 64 bit build
> on an Intel CPU.)
Did you test that with a optimized build?
Andres