Speed select

[MKang3]

In my understanding, linux should able to adjust individual CPU freq, what's the different that compare to Intel Speed Select ?

[Wanner_G_Intel]

Hello MKang3, Thank you for posting on this Community. Could you please provide more details about what you would like to know about Intel® Speed Select Technology (Intel® SST)? Wanner G. Intel Customer Support Technician Under Contract to Intel Corporation

[MKang3]

Hi Wanner,

According to https://builders.intel.com/docs/networkbuilders/intel-speed-select-technology-base-frequency-enhancing-performance.pdf ( test result, figure 3 ) , we can see not only power efficiency got improved but also performance ( throughput ).

Here are some of my questions:

1. It looks CPU need Speed Select feature to get better performance? What if CPU (all cores) already set to max speed ? ( and turbo feature also enabled ), will SST feature still get better performance ?
2. In my understanding, Linux already can set different cores to different freq, what's the difference compare to speed select?

Thank you.

Mark Kang.

[MKang3]

One more question, according to:

https://software.intel.com/en-us/articles/second-generation-intel-xeon-processor-scalable-family-technical-overview

It looks SST-PP and SST-BF both changed base_frequency, what's their major difference between SST-PP and SST-BF ?

Thank you.

Mark Kang.

[Wanner_G_Intel]

Hello MKang3, Thank you for your response. Also, we would like to know the platform you are using (e.g. Intel® Xeon® xxxxx Processor) and what you are trying to achieve or implement with this information. Wanner G. Intel Customer Support Technician Under Contract to Intel Corporation

[MKang3]

Hello Wanner,

Sorry that I am not actually testing it yet but studying this new technology.

Mark Kang.

[Wanner_G_Intel]

Hello MKang3, Thank you for your response. To better assist you, we will do research about this and get back to you soon. Wanner G. Intel Customer Support Technician Under Contract to Intel Corporation

[JoseH_Intel]

Hello MKang3, The following is the information we received from engineering: "2nd Generation Intel(R) Xeon(R) Scalable Processors are the first to support Intel(R) Speed Select Technology (Intel SST). This is a collection of features targeted for handling server data center workloads and usages. Intel SST allows for granular control over the processor frequency in one of two ways: Intel SST - Performance Profile (Intel SST-PP) and Intel SST - Base Frequency (Intel(R) SST-BF). With Intel SST-PP which is for Server Enterprise Infrastructure and Communication Service Providers, processors (SKUs with model numbers ending with Y) can be run at one of three different operating points where the higher core count has lower base frequency and lower core count has higher base frequency. This can be selected via BIOS, certain APIs or 3rd party software. This is helpful because some server workloads benefit from lower core count. To summarize...with Intel SST-PP, instead of buying 3 different processor SKUs for their different server workloads, a data center customers can buy one SKU that can be configured in one of three different core count and base frequency. With Intel SST-BF which is for Network Function Virtualization or network and virtualization workloads, processors (SKUs with model numbers ending with N) can operate some cores at a higher base frequency and other cores at lower base frequency. This is configurable in the BIOS but dependent on software being able to launch high priority workload on appropriate cores. This feature is helpful because cores with higher base frequency can be used for higher/critical priority workloads (i.e. dealing with network bottlenecks) while cores with lower base frequency can be used for lower priority workloads. Intel SST is very much targeted to server data centers that need the flexibility and ability to control modifying the core count and base frequency for certain data center workloads or to run cores at different base frequencies depending on the data center workloads. The description and figures on the following web site helps to describe Intel SST: https://software.intel.com/en-us/articles/second-generation-intel-xeon-processor-scalable-family-technical-overview#inpage-nav-20" In case you have further questions please let me know Jose A. Intel Customer Support Technician Under Contract to Intel Corporation

[MKang3]

Hi Jose,

Thank you for feedback.

I found a website:

https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-a00063934en_us&docLocale=en_US

Q1. It seems when using SST-PP, some cores will be disabled ?

However, according to your description, both SST-PP and SST-BF set some cores to higher base freq and some core to lower base freq.

Q2. According to a Intel github: https://github.com/intel/CommsPowerManagement

It seems we can set cores to different freq without SST feature ?

Thank you.

Mark Kang.

[JoseH_Intel]

Hello MKang3, Thanks for the feedback provided. Just want to let you know that Intel is not accountable for information found on 3rd party websites or OEM advisories. Been said that we will proceed to engage our engineering department about this questions and will update you as soon as we have a response from them. We will appreciate your patience. Jose A. Intel Customer Support Technician Under Contract to Intel Corporation

[JoseH_Intel]

Hello MKang3, The following is the information we received from engineering: "Regarding Q1: Yes, with Intel SST-PP, some cores will be disabled. This feature allows a higher guaranteed base frequency by reducing the number of active cores (lowering the core count). See Figure 19 in this page: https://software.intel.com/en-us/articles/second-generation-intel-xeon-processor-scalable-family-technical-overview Regarding Q2: While they are similar where some cores can operate at different frequencies, Intel(R) Turbo Boost Technology is a different feature than the Intel(R) Speed Select Technology - Base Frequency. The main difference is that Intel SST-BF is optimized for Networking and Network Function Virtualization (NFV) workloads. Please refer to the information on this page: https://www.intel.com/content/www/us/en/architecture-and-technology/speed-select-technology-article.html" I hope this answer your questions. Jose A. Intel Customer Support Technician Under Contract to Intel Corporation

[MKang3]

Hi Jose,

I got it, thank you for your feedback.

Mark Kang.

[JoseH_Intel]

Hello MKang3, You are very welcome. We will proceed to mark this thread as resolved. If you have further issues or questions just go ahead and create a new topic. Jose A. Intel Customer Support Technician Under Contract to Intel Corporation