Mesh test at scale

[Javier Cardona]

Brian,

2009/3/5 Brian DeLacey <bdelacey at gmail.com>:
> Is there any command line program / info that will tell average number of
> hops at reception without instrumenting code?

Not directly, but you might be able to infer it from the stats exposed
via debugfs:

debugfs_netdev.c:
        MESHSTATS_ADD(fwded_frames);   <<<<<
        MESHSTATS_ADD(dropped_frames_ttl);
        MESHSTATS_ADD(dropped_frames_no_route);
        MESHSTATS_ADD(estab_plinks);

Cheers,

Javier


> On Thu, Mar 5, 2009 at 12:45 PM, Javier Cardona <javier at cozybit.com> wrote:
>>
>> Hi Brian,
>>
>> 2009/3/5 Brian DeLacey <bdelacey at gmail.com>:
>> > I have an opportunity to install mesh points on 16 - 25 fresh machines
>> > in a
>> > data center (this weekend).
>>
>> That's great!  That's bigger than our testbed, so I'm eager to see your
>> results.
>>
>> > Are tests worth running at this scale? What functionality should the
>> > tests
>> > cover?
>>
>> Certainly.  Some interesting tests (some require some
>> coding/instrumentation, though)
>>
>> 1.  Coverage,RTT as a function of the number of peers.
>>
>> Set the maximum number of peers on each node to N (mesh_max_peer_links), N
>> > 1.
>> Set the mesh ttl (mesh_ttl) to be equal or higher than the total
>> number of nodes in your mesh.
>> Run a script on each node to ping all other nodes in a round robin
>> fashion.
>> Record the  round trip time and losses.
>> Record the avg. number of hops at reception (this requires adding
>> instrumentation code to the stack).
>>
>> As N decreases, longer routes will have to be used between any two
>> nodes in the mesh.  This will stress route discovery.
>>
>> 2.  Path recovery time.
>>
>> Using iw dev mesh station $HW_ADDR set plink_action block, force
>> multi-hop routes through known nodes.
>> Ping through a multihop path.
>> Measure the effects in the RTT of breaking paths.
>>
>> 3.  Throughput as a function of hops.
>>
>> It is easy to create paths of arbitrary length by blocking peers
>> and/or disabling mesh_auto_open_plinks.
>> With iperf, measure the throughput as a number of hops.
>> You should be getting the familiar 1/n curve for single channel mesh.
>>
>> That should keep you busy over the weekend... ;)
>>
>> Cheers,
>>
>> Javier
>>
>>
>> --
>> Javier Cardona
>> cozybit Inc.
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-- 
Javier Cardona
cozybit Inc.