[darcs-users] Size of patches, import performance, HintsAndTips

Stephen J. Turnbull stephen at xemacs.org
Fri Oct 21 02:48:20 UTC 2005


>>>>> "Adam" == Adam Sjøgren <asjo at koldfront.dk> writes:

    Adam> Given that the directory I imported weighs in at 75MB and I imported
    Adam> it as one patch (one 'darcs record'), maybe I should not be surprised
    Adam> that it took more than 5 minutes of cpu-time, taking up 250+MB RAM to
    Adam> push it from one 2GHz Pentium 4-box to another, over a LAN.

    Adam> My question is this: What is the recommended way to import a 75MB
    Adam> directory?

Juliusz knows the technical stuff, but here's a point of reference.

I use darcs to manage my XEmacs trees, which are of the same order of
magnitude (actually, somewhat bigger).  The numbers you give surprise
me; the initial import (ie, darcs initialize; darcs record --all
--look-for-adds) took around 3 minutes wall clock time on a 1GHz
PowerBook G4.  It's actually not all that much slower than the CVS
checkout (and if I'm checking out from the canonical repository over
the net, CVS is slower).  I've done it several times; that time has
been quite consistent.

New branches (darcs get) take around a minute (on that box, but that's
a reasonable comparision since you report CPU time).  My 2.4GHz Athlon
(32-bit) box died a couple weeks ago, but ISTR that did the import in
well under a minute (faster disk, much faster file system), and new
branches in about 15 seconds.

So the short answer is "darcs get".  You'll have to be patient for the
initial record, that's all.  After that things are not at all bad if
you are simply moving bytes.

Where I find darcs to have performance problems is in dealing with
merges, but that's a different topic that I'm not qualified to discuss
other than to mention my feeling about it.

-- 
School of Systems and Information Engineering http://turnbull.sk.tsukuba.ac.jp
University of Tsukuba                    Tennodai 1-1-1 Tsukuba 305-8573 JAPAN
               Ask not how you can "do" free software business;
              ask what your business can "do for" free software.




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