Tag: intel

Hyper-V CPU Musings

Hyper-V CPU Musings

Recently I had the opportunity arise where I was able to test a few CPU core configurations on an unused host.

My gold here is to see if a CPU virtualization penalty exists and secondarily to see what effect hyperthreading has on CPU performance in a single VM setting.

Specs of the host:  Dual Xeon Gold 6144, 512GB RAM, SSD

HyperV version:  Windows 2016 (long term branch)

To start, here are the Cinebench R15 scores before HyperV was installed:

Hyperthreading enabled got a score of 3427 (left) whereas hyperthreading disabled got a score of 2680:

                            

Next, installed Hyper-V, built a VM running the full GUI of 2012R2, fully updated.

First test, hyperthreading disabled, VM has 16 cores assigned:

Nice!! only 2 points off of the physical.

Now, enable hyperthreading at the host level.  VM still has 16 cores assigned:

Ouch, 1021 points lower (-38%).  Keep in mind all we did was enable hyperthreading on the host.  A 38% penalty just in that setting.

Next test, assign 32 cores to the same VM:

Above 3000 again.  191 points off (-5%) the physical install benchmark above.

And just because, 24 cores assigned to the VM:

Here we have 511 points off the physical host (-15%).

Conclusion:

What did I learn?  With hyperthreading disabled, there is a virtualization penalty, but it barely registers.

It’s when hyperthreading is enabled that one has to be careful.  That large of a hit (-38%) is interesting to say the least.

That being said, with hyperthreading enabled and you assign all available logical cores to the VM, it wasn’t too shabby.

***DISCLAIMER*** I am not responsible for this breaking or damaging any of your stuff.  Copyrights belong to their original owners***

Intel Hyperthreading… worth it?

Intel Hyperthreading… worth it?

In a recent post, I listed a benchmark using Cinebench R15 on a pair of Xeon Gold 6144 CPU’s.  In that post, I mentioned that hyperthreading was enabled.  How much of a difference did that make?

To recap, here’s the full 16 physical/32 logical benchmark:

And now, hyperthreading disabled:

And there we go.  Hyperthreading adds another 747 points, for an increase of nearly 28%.

Oddly, that goes in line with something I read before where hyperthreading can add up to a 25% increase in performance (on physical hardware).  Sadly I can’t remember where I read that, or when.

***DISCLAIMER*** I am not responsible for this breaking or damaging any of your stuff.  Copyrights belong to their original owners***

Upgrading to a current gen Xeon… worth it?

Upgrading to a current gen Xeon… worth it?

Recently I had a chance to introduce a new server into our environment spec’d out to use two CPU’s from Intel’s Xeon Gold family with the same amount of cores as the server it was replacing.  Could their be an increase in CPU performance?

Let’s find out, using a quick and easy way to measure:  Cinebench R15

The old server (Dell R720XD) running two Intel Xeon E5-2667 v2 processors (Ivy Bridge, 8 cores each):

The new server (Dell R740XD) running two Intel Xeon Gold 6144 processors (Skylake-SP, 8 cores each)

BIOS and Power management settings were set to maximum (no power savings, max performance)

So first, 16 cores of Xeon E5-2667v2 (Hyperthreading enabled)

A score of 2464.  No slouch.

Next, 16 cores of Xeon Gold 6144 (Hyperthreading enabled)

Wow, 3427! Almost 1000 points higher, which if my math is right is nearly 40% faster.

Keep in mind this is one benchmark, YMMV, but it’s an easy way of showing the difference you can gain in three generations of CPU’s.

***DISCLAIMER*** I am not responsible for this breaking or damaging any of your stuff.  Copyrights belong to their original owners***