Re: [PATCH 0 of 3 v5/leftover] Automatic NUMA placement for xl

[David Vrabel <dvrabel@cantab.net>]

On 16/07/12 18:13, Dario Faggioli wrote:
> Hello again,
> 
> This is a new version (fixing a small bug) of this series:
> <patchbomb.1341932613@Solace>, which in turn was a repost of what remained
> un-committed of my NUMA placement series.

Whilst I don't think this should prevent the merging of this series now,
I think there needs to be some sort of unit tests for the placement
algorithm before the 4.2 release.

I think the tests should test a representative sample of common system
configurations, available memory and VM memory requirements.  I'd
suggest you'd be looking at 100s of test cases here for reasonable coverage.

One method would be to start with various 'empty' systems and pile as
many differently sized VMs as will fit.  You may want both fixed test of
reproducible tests and random ones.

Some means of automatically verifying the quality of the result at each
stage would be essential.

Without a comprehensive set of tests, tweaking the algorithm/heuristics
has a high risk of introducing regressions.

Having the ability to specify specific setups so you can (e.g.) run
tests when someone reports sub-optimal performance with their particular
setup would also be useful.

David