[darcs-users] darcs-benchmark 0.1.9 - benchmarking darcs-1

[Eric Kow]

Hi Nathan and Petr:

On Fri, Aug 20, 2010 at 17:09:14 +0200, me at mornfall.net wrote:
> So to break down, it seems to me:
> - whatsnew and pull 1000 are faster with darcs 2
> - record, revert, unrevert are about the same
> - pull 100, check, repair are faster with darcs 1
 
> - darcs 2 full get is slower and lazy get is faster than darcs 1 get

Thanks to Nathan and Petr for their respective benchmarking and
distillation efforts.  I can see four things to attend to from
this thread:

1. benchmark for darcs add (now filed)
2. darcs performance regression
3. darcs-benchmark support for darcs-1.0.9 
4. notion of repository variants

For #2, is the take-home message for me that hashed repositories are
still enough of a performance regression for you to stick with darcs
1.0.9 and old-fashioned?  Or is the picture slightly rosier than that?
If it's a ":-(" for this issue, then I think we should care more about
#3 and #4

For #3, I've filed a couple of tickets in the experimental
darcs-benchmark database, (c3b/159 for 'Prelude.read: no parse'; and
c3b/139 for explicit darcs-1 support).  I realise these bug numbers for
an obscure in-repo tracker aren't exactly useful to you.  I'm mainly
just trying to communicate that your reporting these things has caused
some part of the Darcs development machinery to go "ping!", hopefully in
a useful way.

For #4, Nathan, you asked about repository variants. It's useful to note
that these variants are only created once.  Darcs recognises a
pre-existing variant by their prefix, eg. variant.cap-op and knows not
to re-create it.  So for what we'd want to do, darcs-benchmark would
already see that you have an variant.cap-old directory and not bothering
recreating it.

> Also it seems that darcs 2 is quite memory-hungry compared to darcs 1.
> 
> Could you maybe share the output of "darcs chan --from-tag . --count"? The
> record times seem quite exorbitant to me... Maybe also
> "find -maxdepth 1 -type f | wc -l" and "find -type f | wc -l"

Petr: about #2, does Nathan's reply provide all the information you
could use for now? [I guess I'll just leave #2 in your hands, but since
I was replying anyway...]


-- 
Eric Kow <http://www.nltg.brighton.ac.uk/home/Eric.Kow>
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