Turbo Boost on HP Z class workstations

[MAitc]

Hi there,

I'm trying to get some stats / telemetry off our workstations to determine processor frequencies and if our machines are using turbo boost or not.

At present, we're running unbuntu 16.04 with a 4.9.5 kernel.

I've been doing a bit of reading on this - found that I can't rely on the contents of /proc/cpuinfo, as that only shows non-turbo freq information.

I found this 3rd party tool (which may or may not be accurate for Xeons): http://manpages.ubuntu.com/manpages/xenial/man1/i7z.1.html Ubuntu Manpage: i7z - A better i7 (and now i3, i5) reporting tool for Linux.

plus other tools like https://github.com/cyring/CoreFreq GitHub - cyring/CoreFreq: CoreFreq is a CPU monitoring software designed for the 64-bits Processors.

but I wondered if there were any intel issued linux based CPU statistical tools?

I also have some other questions.

How many cores can turbo? (ie, my crude understanding was that some cores had to be more or less idle, in order to let turbo boost 'overclock' the other cores - but maybe thats not quite correct? I know power/heat is a factor also.)

Does hyperthreading change the behaviour of turbo mode?

It appears that turbo boost v2 is all CPU, so OS agnostic, but v3 appears to currently only support windows as its more of a driver / application thing. Will this be release for linux also?

Cheers

[idata]

Hello, keyman26. Thank you very much for contacting the Intel Communities Team.

In this case, the only tool available to check or manage the CPU stats is the https://downloadcenter.intel.com/download/24075/Intel-Extreme-Tuning-Utility-Intel-XTU- Intel® Extreme Tuning Utility nonetheless, is only available for Windows* OS. Furthermore, the Turbo Boost Technology will automatically detect how many cores should be boosted but not all the cores will be boosted at the same time or, they will not reach its maximum frequency simultaneously. Then, the https://www.intel.com/content/www/us/en/architecture-and-technology/hyper-threading/hyper-threading-technology.html Hyper-Threading Technology will not change the behavior of the turbo mode. Finally, the Turbo Boost Technology V3 will come with the processor but the software is only for Windows* OS. I recommend you to get in touch with the support group of your Linux version to double check if they are planning to develop this type of software for this technology.Antony S.

[MAitc]

Thanks for the prompt response Antony,

Very helpful. I noted that Intel Extreme Tuning Utility only appears to support a range of i3 through to i9 CPUs. Does it also support Xeon cpus, or can we not rely on it to give accurate results on Xeon architecture?

one more question - though this may not be easily answerable - but roughly how many cores could I expect to run at maximum turbo boost speed? eg, if I have a 6 core Xeon E5-1650 v4, is it possible to achieve having 2 of those cores running at the 4GHz speed (at least until the temp makes that untenable)

[CCOUR4]

Hello,

You will get turbo ratios by 1, by 2 etc by reading register

MSR_TURBO_RATIO_LIMIT

Linux provides the kernel module msr.ko for such query; msr hexa values are given into the msr-index.h

CoreFreq will provide you the same but with bit values decoded for human.

I have a chance to test a few range of Xeon. However you can boot its live CD to spare you FS in case of crash.

[MAitc]

I've installed turbostat and thats given me the info I was after - able to observe cores going into turbo mode when apps push them hard enough.

interesting to see most of the cores idling along at 1.2Ghz (way below the listed 'base' speed of 3Ghz.. but then surging up to 3.7Ghz.

I found a little tool that is very mean to CPUs, and ran it about 6 times, and 6 of my 24 cores dutifully ramped up to 3.7GHz, which was nice to see. Not sure how many cores I can push that hard before thermal protections kick in.

[CCOUR4]

Indeed with SpeedStep EIST and Turbo activated, Core Frequency fluctuates from the minimum operating ratio up to the the highest turbo turbo.

A few msr registers provide those ratios.

The Linux governor (ondemand, performance,...) can also makes the difference when system is idling.

Like turbostat, CoreFreq provides an estimation of the core frequency over an interval of time (1 second)

CoreFreq driver allows you to decrease the interval down to 100 ms and will display a red HOT indicator whenever the throttling bit is set.

You can experiment the deactivation of Turbo and EIST in the "Technology" window then in the "Tool" window, choose a stress function such as random or round robin turbo to find your appropriate performance settings while monitoring core temperature and throttling in the "Frequency" view.