Written by  David J Morse and John Beckett, Solutions Performance Analysis, and Mukund Khatri, Server Advanced Engineering

When most customers think of Dell’s 12th Generation PowerEdge servers, they focus on the impressive advances in core count, memory speed and capacity, I/O capabilities, and enhanced iDRAC management interfaces.   Most of these advances show the greatest benefit in applications where the focus is increased throughput.  However, there are a growing number of customers who evaluate server platforms in a different manner altogether.  These organizations, primarily in financial services industry, are interested not so much in how much total work can be done on a server at any given time, but how quickly individual requests can be sent and received across high speed networks, and how predictable the overall response time of the system is across all the processor cores.

For these customers, the name of the game is low latency.  They are willing to tweak every BIOS knob, research every Operating System service, and optimize their environments to gain even a tiny advantage in overall system latency.  These customers have had great success with Dell’s previous generation of servers, and have eagerly evaluated new Dell 12th Generation PowerEdge offerings to understand the advantages that the new architecture provides to their environments. 

The default values in the Dell BIOS were chosen to provide the best blend of high performance and power efficiency.  These defaults, while appropriate for the vast majority of customers, can be optimized for low latency environments.

In order to assist these customers in making the correct choices, Dell Server Advanced Engineering and System Performance team members have researched all of the BIOS knobs available on 12th Generation servers in order to provide a “best-case” set of tunings for low latency environments.  These optimal BIOS tunings will be a great place to start for these low latency customers, and could save them days of testing to find these combinations on their own.

We approached the testing from two perspectives:  to evaluate impacts on lowest latency ping pong tests over a high speed specialized network adapter, and evaluating response times across all cores to ensure the response times were consistently minimized.  After days of testing and validation, we have rolled our findings into a whitepaper entitled Configuring  Low-Latency Environments on Dell 12th Generation PowerEdge Servers.

Something we are sure will interest these customers is the behavior of Intel Turbo Technology v2.0 , as compared with the previous generation.  The new implementation of Turbo for the Intel Xeon E5-2600 series of processors is considerably more consistent in providing frequency uplift, and the ability to sustain higher frequencies is improved over previous generations.  Although Turbo was beneficial in some of our testing, we still recommend Turbo be disabled, since we can’t know the details of every customer’s thermal environment which may impact the operation of Turbo mode.  We do, however, encourage customers to experiment with Turbo mode for themselves, as we expect there will be some cases where leaving Turbo Mode enabled may provide benefits.

We hope that these customers will take the time to evaluate our whitepaper, and let us know in the comments if it was helpful for their use cases.