[openstack-dev] [oslo.messaging] Performance testing. Initial steps.

Gordon Sim gsim at redhat.com
Tue Jan 27 20:26:25 UTC 2015

On 01/27/2015 06:31 PM, Doug Hellmann wrote:
> On Tue, Jan 27, 2015, at 12:28 PM, Denis Makogon wrote:
>> I'd like to build tool that would be able to profile messaging over
>> various deployments. This "tool" would give me an ability to compare
>> results of performance testing produced by native tools and
>> oslo.messaging-based tool, eventually it would lead us into digging into
>> code and trying to figure out where "bad things" are happening (that's
>> the
>> actual place where we would need to profile messaging code). Correct me
>> if
>> i'm wrong.
> It would be interesting to have recommendations for deployment of rabbit
> or qpid based on performance testing with oslo.messaging. It would also
> be interesting to have recommendations for changes to the implementation
> of oslo.messaging based on performance testing. I'm not sure you want to
> do full-stack testing for the latter, though.
> Either way, I think you would be able to start the testing without any
> changes in oslo.messaging.

I agree. I think the first step is to define what to measure and then 
construct an application using olso.messaging that allows the data of 
interest to be captured using different drivers and indeed different 
configurations of a given driver.

I wrote a very simple test application to test one aspect that I felt 
was important, namely the scalability of the RPC mechanism as you 
increase the number of clients and servers involved. The code I used is 
https://github.com/grs/ombt, its probably stale at the moment, I only 
link to it as an example of approach.

Using that test code I was then able to compare performance in this one 
aspect across drivers (the 'rabbit', 'qpid' and new amqp 1.0 based 
drivers _ I wanted to try zmq, but couldn't figure out how to get it 
working at the time), and for different deployment options using a given 
driver (amqp 1.0 using qpidd or qpid dispatch router in either 
standalone or with multiple connected routers).

There are of course several other aspects that I think would be 
important to explore: notifications, more specific variations in the RPC 
'topology' i.e. number of clients on given server number of servers in 
single group etc, and a better tool (or set of tools) would allow all of 
these to be explored.

 From my experimentation, I believe the biggest differences in 
scalability are going to come not from optimising the code in 
oslo.messaging so much as choosing different patterns for communication. 
Those choices may be constrained by other aspects as well of course, 
notably approach to reliability.

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