[CentOS] Intel turbo mode

[Stephen John Smoogen]

On 3 October 2017 at 13:01, hw <hw at adminart.net> wrote:
> Stephen John Smoogen <smooge at gmail.com> writes:
>
>> On 1 October 2017 at 11:34, hw <hw at adminart.net> wrote:
>>> Hi,
>>>
>>> is there a way in Centos to find out if the Intel turbo mode will be
>>> used?
>>>
>>> Using the 'stress' utility and checking the frequency with cpupower
>>> tells me that a CPU is running at it´s maximum frequency as reported by
>>> cpupower --- and this frequency is less than the frequency it would run
>>> at if it used the turbo mode.  All the other CPUs are at their minimum
>>> frequency.  I have verified that turbo mode is enabled in the BIOS.
>>>
>>> Is cpupower unable to report frequencies used in turbo mode despite it
>>> always says it gets its information from the hardware?
>>>
>>
>> It would seem that there are multiple ways to get the information you
>> are looking for. I expect you have seen this already
>>
>> https://haypo.github.io/intel-cpus.html
>>
>> but I figured I would pass it on for others. They found that cpupower
>> is less reliable in how it reports the data because of the values it
>> gets them from.
>
> Thanks, I didn´t see that one yet.  At least I noticed that cpupower
> says that turbo mode is available, and turbostat seems to indicate that
> CPUs sometimes run at higher frequencies like they would when in turbo
> mode.
>
> It´s strange that there is no tool to definitely figure this out,
> especially since RH seems to have done a lot of research into improving
> performance.
>

My limited understanding is that it isn't very reliable to show it and
the Windows ones distort reality a lot (aka say you are in it when you
aren't actually in it) because they do a moving average to show what
is going on so it doesn't look as jagged as it really is. It is also
not all that useful for general software needs. The CPU is going to be
waiting a lot longer now for memory and io to catch up for most
transactions.

-- 
Stephen J Smoogen.