[darcs-devel] New performance regression?

[David Roundy]

On Fri, Feb 08, 2008 at 10:53:57AM +0000, Simon Marlow wrote:
> David Roundy wrote:
> > On Thu, Feb 07, 2008 at 03:26:09PM +0000, Simon Marlow wrote:
> >> I just updated my darcs2 to try out the new ByteString changes and see if I 
> >> could reproduce Erik's results, and I'm seeing a bit regression in the 
> >> performance of unpull:
> > 
> > I'll try to take a look at this tomorrow... I've spent my darcs time for
> > the day working out zooko's performance regression.  Who knows, maybe I've
> > fixed yours?  :)
> 
> I just updated and tried again, and now pull has regressed too, by an order 
> of magnitude :-(

Argh.  That's odd, my testing (which is on a --hashed repository) suggests
that pull still hasn't regressed, although I can reproduce your unpull
regression.

> You should be able to reproduce this pretty easily with a darcs2 ghc 
> repository.  I get no progress messages at all from pull for quite a while, 
> and the 400-patch pull now takes over 100s where it previously took 10. 
> Unpull is also taking about 100s on this machine, where previously it took 15.

Oddly enough in my quick darcs2-format test, I don't see the slowdown, but
on the hashed-format test I do.  This may be some sort of hysteresis
effect.  I'll try using your darcs2 repository, but first I want to debug
the darcs get slowness (or at least lack of progress).  :(
-- 
David Roundy
Department of Physics
Oregon State University