[Haskell-cafe] Re: darcs 2.4 release candidate 2

Ben Franksen benjamin.franksen at bessy.de
Fri Feb 19 13:49:26 EST 2010

Hi All

This rc release is still notably slower on some operations than older
releases. My test case is a large project named RTEMS (a real-time OS),
that we wish to import into darcs (at work) to better track our own
additions and modifications.

To repeat, download two adjacent releases, e.g.

wget http://www.rtems.org/ftp/pub/rtems/4.9.0/rtems-4.8.1.tar.bz2
wget http://www.rtems.org/ftp/pub/rtems/4.9.0/rtems-4.9.0.tar.bz2

unpack, initialize darcs and record in the 4.8.1 tree, then copy _darcs to
the 4.9.0 version and try to record -l or whatsnew -l.

I have two darcs versions installed:

ben at sarun[1]: .../rtems/rtems-4.9.0 > /usr/local/bin/darcs --version
2.2.1 (release)
ben at sarun[1]: .../rtems/rtems-4.9.0 > darcs --version (release candidate 2)

ben at sarun[1]: .../rtems/rtems-4.9.0 > time /usr/local/bin/darcs whatsnew -l
# ...long output elided...
/usr/local/bin/darcs whatsnew -l  381,45s user 6,34s system 92% cpu 7:00,90

whereas with it goes

ben at sarun[1]: .../rtems/rtems-4.9.0 > time darcs whatsnew -l

Well, it is still running after 18 minutes! Top reports something like

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND           
 5702 ben       20   0 1112m 933m 3628 R 92.2 28.3  18:26.08 darcs              

One point to notice is that has not yet reported any progress,
whereas 2.2.1 almost immediately starts reporting something about pristine
trees followed by the usual number/number stuff; and the numbers
continually rise.

The situation with record is similar.

I admit that the huge RTEMS tree with over 7000 changes between the two
releases is challenging. However, earlier releases can do it (though it
takes long, much longer than with, say, mercurial). At work I tried it with
2.3.1 (on a fast 4 processor machine) and it recorded all the changes in
about one minute.

I think this regression should be fixed before 2.4 is released.


Reinier Lamers wrote:
> The darcs team would like to announce the immediate availability of darcs
> 2.4 release candidate 2. darcs 2.4 will contain many improvements and
> bugfixes compared to darcs 2.3.1. Highlights are the faster operation of
> record, revert and related commands, and the experimental interactive hunk
> editing. This beta is your chance to test-drive these improvements and
> make darcs even better.

More information about the Haskell-Cafe mailing list