usertest notes

[John Arbash Meinel]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Martin Pool wrote:
> On Fri, Sep 26, 2008 at 1:57 PM, Robert Collins
> <robertc at robertcollins.net> wrote:
>> I'd love to see networking ones to aid the stuff andrew is working on.
> 
> Me too; let me sketch out the path to that.
> 
> We need to add some test scenarios (according to
> http://people.ubuntu.com/~ianc/plugins/usertest/doc/usertest-tutorial.html)
> for network operations.
> 
> We also need to choose whether to measure them in real elapsed time or
> by counting roundtrips.  For things inside selftest I think counting
> effort is best; for usertest measuring real time is good.  To use the
> same method as in <http://bazaar-vcs.org/SmartPushAnalysis1.4> we can
> use netem, which must be configured by root, so we need to ask the
> sysadmins to set it up on escudero.   And of course we have to
> actually set up
> 
> <http://www.linuxfoundation.org/en/Net:Netem> shows how we can filter
> based on destination address with something like this:
> 
>   tc qdisc add dev lo root handle 1: prio
>   tc qdisc add dev lo parent 1:3 handle 30: netem delay 500ms
>   tc qdisc add dev lo parent 30:1 handle 60: tbf rate 100kbit buffer
> 1600 limit 3000
>   tc filter add dev lo protocol ip parent 1:0 prio 3 u32 match ip
> dport 4155 0xffff flowid 60:1
> 
> This is not precisely the same as what we were previously using
> because it has a bandwidth limit as well as a delay limit.  (In
> practice I believe the previous delay limit was such that tcp
> windowing stopped it every using the full nearly-infinite bandwidth.)

It might be nice to have a couple of different ports filtered at
different levels. It might also be nice to see the difference between
'bzr+ssh' and raw 'bzr', though I'm not sure if you gain a lot there.

John
=:->

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (Cygwin)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEARECAAYFAkjdXX8ACgkQJdeBCYSNAAMX0wCgh2L+UVJAELvXnrk6FM+/T28F
jL0An0ZaddlfcVUx3LzXRpjJEuhaJQ9c
=402e
-----END PGP SIGNATURE-----