perfSONAR User Q&A and Other Discussion

[Aaron Brown <>]

Hey David,

On May 14, 2014, at 12:54 PM, David A. J. Ripley 
<>
 wrote:

> 
> Hi there; I'm looking at setting up a perfsonar test point that will be 
> used *only* for ad-hoc testing - getting that out there first, because this 
> is (I think) a separate issue from the upcoming unified scheduler:
> 
> Is there a current best practice for having owamp and bwctl available on 
> the same host, while keeping them from stepping on each others toes? (I can 
> use separate NICs for each service, but that creates a different set of 
> challenges.)
> 
> Based on the docs, it would seem that since bwctl 1.5.1, having testers use 
> only the bwctl/bwping clients (rather than iperf/owping etc directly) will 
> take care of things, but I'm just checking to see if there are 
> other/different/better ways.

The two basic options are pretty much what you listed. The only other one I 
can think of would be to try to use tc to do some priority queueing to 
prioritize owamp packets over non-owamp packets. Unfortunately, 
differentiating owamp traffic for these purposes is somewhat awkward. It’d 
probably be feasible to do it via packet marking based on user id (i.e. user 
owamp), but if clients were going to be run on that host too, you’d probably 
need to make owping/powstream setuid so that they’d run as the user ‘owamp’ 
no matter who ran them. As my caveat laden previous statements should imply, 
this has been in no way tried, nor the results verified :)

If you’re going to go the bwctl route, i’d suggest going with 1.5.2 (an -rc 
has currently been released) as that handles ‘owamp’ tests much better.

Cheers,
Aaron

> 
> Thanks!
> 
> D.
>