[tahoe-dev] new wiki page about performance and benchmarks

[Zooko O'Whielacronx]

Folks:

I updated this page on the wiki:

http://tahoe-lafs.org/trac/tahoe-lafs/wiki/Performance

to describe and link to various benchmark results on Tahoe-LAFS v1.8.0
release candidates.

If you have any newer benchmark results, better docs or links to
better data, etc., then please update that wiki page! Appended is the
version of that page that I just posted.

Regards,

Zooko

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In late 2010 Kyle Markley did some benchmarking of what were then the
release candidates for Tahoe-LAFS v1.8.0. This helped us catch two
major performance regressions in Brian's New Downloader and helped
make Tahoe-LAFS v1.8.0 into an excellent new release (see epic ticket
#1170 for mind-numbing details). Kyle also contributed code for his
benchmarking scripts (in Perl), but nobody to my knowledge has yet
tried to re-use that script.

    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-July/004776.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-July/004781.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-July/004782.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-July/004838.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-August/004853.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-August/004985.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-August/005007.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-August/005011.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-September/005155.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-September/005162.html

We also experimented with different segment sizes and immutable
uploader pipeline depths, and the results tentatively confirmed that
the current segment size (128 KiB) and immutable uploader pipeline
depth (50,000 B) were better on both of Kyle's networks than any of
the alternatives that Kyle tried.

Along the way Terrell Russell did some benchmarking and contributed a
bash script which I used several times during the process:

    * http://tahoe-lafs.org/trac/tahoe-lafs/ticket/1170#comment:81

At about the same time Nathan Eisenberg of Atlas Networks did a couple
of manual benchmarks:

    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-August/004929.html
    * http://tahoe-lafs.org/pipermail/tahoe-dev/2010-August/004929.html

Also François Deppierraz has run a few benchmarks. (Can't find a link
to his results.)

What we really want, of course, is automated benchmarks that get
executed at regularly scheduled intervals, or whenever a new patch is
committed to revision control, or both. This would ideally run on some
dedicated hardware or at least on some virtualized hardware which had
a fairly consistent load of other tenants, so that the resulting
measurements would not get too much noise from other people's
behavior. You can see on Performance/Old that we used to have such an
automated setup, including graphs of the resulting performance.