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["Mark Washenberger" <mark.washenberger@xxxxxxxxxxxxx>]

Yun,

I was working with a very small but fairly realistic setup. In this
case I had only 3 Xen hosts, no more than 10 nova vms up at a time.
And the environment was very nearly "fresh" so I believe the db 
tables were as small as they could be. I believe the utilization
across the board in my setup was very low, and indeed the numbers
were very consistent (I ran a large number of times, but didn't
save all of the data :-(). Also, there were only 2 compute nodes
running, but as the workflow only had rpc casts, I'm not sure that
really mattered very much.

The profile I gave was for vm creation. But I also ran tests for
deletion, listing, and showing vms in the OS API.

Networks were static throughout the process. Volumes were absent.

"Yun Mao" <yunmao@xxxxxxxxx> said:

> Hi Mark,
> 
> what workload and what setup do you have while you are profiling? e.g.
> how many compute nodes do you have, how many VMs do you have, are you
> creating/destroying/migrating VMs, volumes, networks?
> 
> Thanks,
> 
> Yun
> 
> On Fri, Mar 23, 2012 at 4:26 PM, Mark Washenberger
> <mark.washenberger@xxxxxxxxxxxxx> wrote:
>>
>>
>> "Johannes Erdfelt" <johannes@xxxxxxxxxxx> said:
>>
>>>
>>> MySQL isn't exactly slow and Nova doesn't have particularly large
>>> tables. It looks like the slowness is coming from the network and how
>>> many queries are being made.
>>>
>>> Avoiding joins would mean even more queries, which looks like it would
>>> slow it down even further.
>>>
>>
>> This is exactly what I saw in my profiling. More complex queries did
>> still seem to take longer than less complex ones, but it was a second
>> order effect compared to the overall volume of queries.
>>
>> I'm not sure that network was the culprit though, since my ping
>> roundtrip time was small relative to the wall time I measured for each
>> nova.db.api call.
>>
>>
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