[openstack-dev] [oslo.messaging] Performance testing. Initial steps.
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
>> actual place where we would need to profile messaging code). Correct me
>> 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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