Solved

Non-uniform PCIe Access - are any OSs "NUPA" aware?

Posted on 2012-12-26
5
381 Views
Last Modified: 2016-11-23
Wondering which PCIe slots to use on dual Intel CPU E5 based servers, and whether any operating system know how to load balance to keep PCIe access local to the CPU.

It's well known that modern OSs are NUMA aware and will try to allocate RAM/cores so that memory access is local rather than across the hypertransport/quickpath busses because modern CPUs have inbuilt memory controllers.

What about PCIe cards though now that the PCIe controllers are built into the CPUs rather than on the southbridge? Say for example I have a HP DL380 gen8 or Dell R720 with two CPUs and I put dual port NICs in slots 1 and 4 and teamed them together for 4*1Gb, would the OS be clever enough to know that slot 1 was on CPU1 and slot 4 was on CPU2 and direct the outbound packets to the local NIC or would half of the traffic go over the HT bus in a random manner? Is there any benefit of spreading NICs and FC HBAs over both CPUs inbuilt PCIe controllers?

I'm going to sleep on it and see if anyone knows for sure.
0
Comment
Question by:andyalder
  • 3
  • 2
5 Comments
 
LVL 117

Accepted Solution

by:
Andrew Hancock (VMware vExpert / EE MVE) earned 500 total points
Comment Utility
Andy, it's an excellent question, and we've been asking ourselves the same question and testing with recent large cluster deployments of Dell R720s, and which PCIe slots, to insert quad Broadcom network cards, to network team with Windows 2012 Hyper-V.

at present, after much testing, an high network I/O, and performance monitoring, it's difficult to ascertain, and draw any conclusions, and we have raised this Service Request to our Technical Specialist at Dell!
0
 
LVL 55

Author Comment

by:andyalder
Comment Utility
Did Dell come back with anything? It's really a question for the likes of VMware, MS and the NIC/HBA manufacturers to address rather than the server makers. I think we have to assume there's nothing that uses locality in load balancing at the moment so we might as well just put the cards on any CPU and get average 50% local traffic.

Not sure if there is a heat/turbo gain to spreading the cards over both CPUs, if the processors and airflow were identical then maybe the additional heat from the PCIe controller part of the chip might come into play and slow the CPU on that die down but that would be delving into the 1-2% speed improvements you can get by picking the fastest of a particular chip part number.
0
 
LVL 117

Expert Comment

by:Andrew Hancock (VMware vExpert / EE MVE)
Comment Utility
Dell still sleepy mode over Chrimbo!
0
 
LVL 55

Author Comment

by:andyalder
Comment Utility
EE is chasing as abandoned so I'll close. Guess it doesn't matter much which CPU the peripherals are on at the moment otherwise the manufacturers would be shouting about slight speed improvements from clever drivers.
0
 
LVL 117

Expert Comment

by:Andrew Hancock (VMware vExpert / EE MVE)
Comment Utility
still in Dell Escalation Team, bookmarked the question, so will post back here, or catchmeup through profile!
0

Featured Post

Threat Intelligence Starter Resources

Integrating threat intelligence can be challenging, and not all companies are ready. These resources can help you build awareness and prepare for defense.

Join & Write a Comment

It Is not possible to enable LLDP in vSwitch(at least is not supported by VMware), so in this article we will enable this, and also go trough how to enabled CDP and how to get this information in vSwitches and also in vDS.
HOW TO: Install and Configure VMware vSphere Hypervisor 6.5 (ESXi 6.5), Step by Step Tutorial with screenshots. From Download, Checking Media, to Completed Installation.
Teach the user how to join ESXi hosts to Active Directory domains Open vSphere Client: Join ESXi host to AD domain: Verify ESXi computer account in AD: Configure permissions for domain user in ESXi: Test domain user login to ESXi host:
In this Micro Tutorial viewers will learn how they can get their files copied out from their unbootable system without need to use recovery services. As an example non-bootable Windows 2012R2 installation is used which has boot problems.

772 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

10 Experts available now in Live!

Get 1:1 Help Now