DragonFly master now runs on the Threadripper 2990WX

[Freddie Cash]

On Fri, Aug 17, 2018, 9:43 PM Matthew Dillon, <dillon at backplane.com> wrote:

> A few minor commits and DragonFly master is now able to run on the new
> threadripper.  The cpu is a real beast, packing 32 cores and 64 threads.
> It blows away our dual-core Xeon to the tune of being +50% faster in
> concurrent compile tests, and it also blows away our older 4-socket Opteron
> (which we call 'Monster') by about the same margin.  It's an impressive CPU.
>
> For now the new beast is going to be used to help us improve I/O
> performance through the filesystem, further SMP work (but DFly scales
> pretty well to 64 threads already), and perhaps some driver to work to
> support the 10gbe on the mobo.  Fortunately the mobo I have also has two
> 1gig NICs that we already support well).
>
> -Matt
>

Have you done any work on the scheduler to work with the very NUMA nature
of the Threadripper 2 WX models?

16 of the CPU cores have direct access to the memory controller and PCIe
lanes, while the other 16 do not, increasing the latency for any memory/bus
accesses.

Workloads that rely more on CPU resources than memory scale really well on
the 2990WX/2950WX. But those that rely on memory or disk I/O will depend on
the intelligence of the scheduler for their scaling.

This is one of the reasons Windows runs slower than Linux on the
2950WX/2990WX. The Windows scheduler treats all the cores the same and just
does a round-robin to available cores. They've added some basic weighting
to the two types of cores, but haven't done anywhere near the taking the
Linux devs have.

Will be interesting to watch how benchmark scores change after every patch
Tuesday, as the Windows devs tweak the scheduler to work with the different
cores in the TR2.

Cheers,
Freddie

Typos courtesy of my phone's keyboard.

>
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