White Papers

ManualsBrandsDell ManualsConverged InfrastructureHigh Performance Computing Solution Resources

Impact of Broadwell BIOS

Options On CAE Applications

Authors: Mayura Deshmukh, Ashish K Singh, Neha Kashyap

Last week’s blog on the “Broadwell Performance for HPC” series described the BIOS options and compared

performance across generations of processors for molecular dynamic applications (NAMD) and Weather Research

and Forecasting (WRF). This blog, third in the series, focuses on BIOS options for some HPC CAE applications for

five different Broadwell Intel Xeon E5-2600 v4 series processor models. It aims to answer questions like, which snoop

mode works best for my application and processor? Which BIOS System Profile would give the best performance?

There have been a few changes in the BIOS options for Broadwell as compared with the previous generation

(Haswell). One of the major additions in the Broadwell BIOS is the “Opportunistic Snoop Broadcast” snoop mode in

the Memory settings. This blog discusses performance of the applications for all four snoop modes: Opportunistic

snoop broadcast (OSB), Early snoop (ES), Home snoop (HS) and Cluster on die (COD). For more information on the

new BIOS options and snoop modes check blog one of this series.

The Dell BIOS “System Profile” setting can be set to either of the four pre-configured profiles: Performance Per Watt

(DAPC), Performance Per Watt (OS), Performance (Perf.) and Dense Configuration or set to Custom. In the pre-

configured profiles the Turbo Boost, C States, C1E, CPU Power Management, Memory Frequency, Memory Patrol

Scrub, Memory Refresh Rate, Uncore Frequency are preset whereas for Custom the User can choose values for

these options. For more information on System Profiles check the link. DAPC and OS have shown to perform

similarly in past studies, and Dense Configuration performs lower for HPC workloads, so we will be focusing on

DAPC and Performance Profiles in this study. The DAPC (Dell Active Power Control) Profile relies on a BIOS-centric

power control mechanism. Energy efficient turbo, C States, C1E are enabled with the DAPC Profile. Performance

Profile disables power saving features such as C-states, Energy efficient turbo and C1E. Turbo boost is enabled in

both the System Profiles.

This blog discusses the performance of CAE applications with DAPC and Performance profile for each of the four

snoop modes for five different Intel Xeon E5-2600 v4 series Broadwell processors. Table 1 shows the application and

benchmark details and Table 2 describes the server configuration used for the study.

Table 1 - Applications and benchmarks

Summary of content (8 pages)

PAGE 1
Impact of Broadwell BIOS Options On CAE Applications Authors: Mayura Deshmukh, Ashish K Singh, Neha Kashyap Last week’s blog on the “Broadwell Performance for HPC” series described the BIOS options and compared performance across generations of processors for molecular dynamic applications (NAMD) and Weather Research and Forecasting (WRF). This blog, third in the series, focuses on BIOS options for some HPC CAE applications for five different Broadwell Intel Xeon E5-2600 v4 series processor models.
PAGE 2
Application LS-DYNA® Version 8.0.0 Metric Elapsed time MPI Platform MPI 9.1.0 Benchmark  car2car with endtime=0.02 STARCCM+® 10.04.011 Average Elapsed time Platform MPI 9.1.3          Civil_20m EglinStoreSeparation HlMach10 Kcs Lemans_100m Lemans_17m Reactor9m TurboCharger Vtm ANSYS® Fluent® v16 Solver rating Platform MPI 9.1.2.1      truck_poly_14m combustor_12m combustor_71m exhaust_system_33m ice_2m OpenFOAM 2.4.0 Clock time Open MPI 1.10.
PAGE 3
Logical Processor - Disabled Power Supply Redundant Policy - Not Redundant Power Supply Hot Spare Policy - Disabled I/O Non-Posted Prefetch - Disabled Snoop Mode - Opportunistic Snoop Broadcast (OSB), Early Snoop (ES), Home Snoop (HS), Cluster on Die (COD) BIOS iDRAC Firmware Node interleaving - Disabled 2.0.0 2.30.30.02 LS-DYNA is a general-purpose finite element program from LSTC capable of simulating complex real-world structural mechanics problems. We ran the car2car benchmark with end time set to 0.
PAGE 4
core for 22 core). All the snoop modes with the System Profile set to Performance follow similar pattern as DAPC. As shown in the graph on the right in Figure 1, changing the System Profile from DAPC to Performance can provide up to 2% performance benefit. The COD.Perf is the best option, about 2-4% better compared to OSB.DAPC across all processor models. The total 2-4% improvement with COD.
PAGE 5
across the benchmark cases across all processor models. After COD and OSB, ES option is better for lower core counts and HS for 16, 20 and 22 core processors. As mentioned previously, the system in ES mode starts paying the penalty of having lower request tokens per core for higher core counts compared to the other snoop modes. Figure 3: DAPC vs. Performance with COD snoop mode for STARCCM+ The graph in figure 3 compares the System Profile BIOS options DAPC and Performance.
PAGE 6
Figure 4: Comparing snoop modes for ANSYS Fluent The graph in Figure 4 shows the performance of truck_poly_14m for all the snoop modes compared to the default OSB.DAPC which is shown as the red baseline in the graphs. All the other benchmarks show a similar pattern. COD performs up to 2% better than OSB for truck_poly_14m, combustor_12m and ice_2m. COD is about 5% better for combustor_71m and 6% better for exhaust_33m.
PAGE 7
better for all the processor models for the larger combustor_71m and exhaust_33m benchmark cases. The Performance profile is 1-3% better for the other benchmark cases. OpenFOAM (Open source Field Operation And Manipulation) is a free, open source software for computational fluid dynamics (CFD). OpenFOAM was compiled with -march=native / Broadwell option.
PAGE 8
Figure 7: Comparing snoop modes and BIOS Profiles for OpenFOAM Motorbike 11M benchmark For the openFOAM motorbike 11M benchmark the OSB, COD and the HS snoop modes perform similarly with about 1% variation. The performance for ES is low across all the processor models and it keeps on dropping as the number of cores increase as shown in the left graph of figure 7. The snoop modes with BIOS System Profile set to Performance follow exactly similar trend.