Open Stack

On 06/01/17 16:35, Thomas Herve wrote:
> Thanks a lot for the analysis. It's great that things haven't gotten off track.
>
>> I tracked down most of the step changes to identifiable patches:
>>
>> 2016-10-07: 2.44GiB -> 1.64GiB
>>  - https://review.openstack.org/382068/ merged, making ResourceInfo classes
>> more memory-efficient. Judging by the stable branch (where this and the
>> following patch were merged at different times), this was responsible for
>> dropping the memory usage from 2.44GiB -> 1.83GiB. (Which seems like a
>> disproportionately large change?)
> Without wanting to get the credit, I believe
> https://review.openstack.org/377061/ is more likely the reason here.

It *is* possible (and I had, indeed, forgotten about that patch), since 
those two backports merged at around the same time. However, that patch 
merged to master on 30 September, a week before the other two patches, 
and there was no (downwards) change in the memory usage on master until 
the day after the other two merged. So the evidence is definitely not as 
clear-cut as with some of the others.

>>  - https://review.openstack.org/#/c/382377/ merged, so we no longer create
>> multiple yaql contexts. (This was responsible for the drop from 1.83GiB ->
>> 1.64GiB.)
>>
>> 2016-10-17: 1.62GiB -> 0.93GiB
>>  - https://review.openstack.org/#/c/386696/ merged, reducing the number of
>> engine workers on the undercloud to 2.
>>
>> 2016-10-19: 0.93GiB -> 0.73GiB (variance also seemed to drop after this)
>>  - https://review.openstack.org/#/c/386247/ merged (on 2016-10-16), avoiding
>> loading all nested stacks in a single process simultaneously much of the
>> time.
>>  - https://review.openstack.org/#/c/383839/ merged (on 2016-10-16),
>> switching output calculations to RPC to avoid almost all simultaneous
>> loading of all nested stacks.
>>
>> 2016-11-08: 0.76GiB -> 0.70GiB
>>  - This one is a bit of a mystery???
> Possibly https://review.openstack.org/390064/ ? Reducing the
> environment size could have an effect.

Unlikely; stable/newton fell too (a few days later), but that patch was 
never backported. (Also, it merged on master almost a week before the 
change in memory use.)

It's likely a change in another repo, but I checked the obvious 
candidates (heatclient, tripleoclient) without luck.

>> 2016-11-22: 0.69GiB -> 0.50GiB
>>  - https://review.openstack.org/#/c/398476/ merged, improving the efficiency
>> of resource listing?
>>
>> 2016-12-01: 0.49GiB -> 0.88GiB
>>  - https://review.openstack.org/#/c/399619/ merged, returning the number of
>> engine workers on the undercloud to 4.