[ofw] Disable WSD by default in MSI

[Fab Tillier]

Hefty, Sean wrote on Fri, 1 Oct 2010 at 12:36:18

>> The current default for the OFED MSI packages is to enable WSD by
>> default. We've seen sporadic issues with WSD, and I'd like to see the
>> default be to not enable WSD.  I'd also like to see ND enabled by
>> default.
>> 
>> This way, when someone installs the MSI, they get the most common
>> settings by default, without introducing instability in socket
>> applications and services.
>> 
>> Thoughts?
> 
> I can't think of any negatives to enabling ND by default.  Is there
> evidence showing that WSD provides enough of a performance benefit to
> keep it enabled by default, given the potential downside?
> 
> Personally, I don't install WSD when installing the OFED package,
> mainly because I want to remove that as a variable in my testing.

For MPI use, WSD sadly does not scale, and the performance just isn't there - the latency is too high, and at large scale it becomes unstable.  Since ND is there, WSD does more harm than good, really.  Plus the defaults would cause people using MSMPI to go over WSD rather than ND, which isn't right.

-Fab