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Configuring RAPL limits in Sandy Bridge Xeon processors

Nobin_M_
Beginner
3,227 Views

Hi,

I am trying to set RAPL limits, so my question is for setting some power limits, do I need to go to each core and set the limits or just set limits in core 0 in a socket. each core I meant writing all the /dev/cpu/<N>/msr nodes in that socket?

Can we set different values in each of the cores in a socket.

-Nobin

0 Kudos
27 Replies
Martin_D_Intel1
Employee
216 Views

ok. I updated the tool to support your cpuid. I will email to you as well. 

thanks

Martin

Nobin_M_
Beginner
216 Views

Hi Martin,

Thanks for the power_gov.

I am using a Ivy Bridge server chip which has 10 cores ( I work for some company).

my RAPL understanding lacks some fundamental knowledge, can you answer the below question.

Lets think only about PKG domain.

We have two power limits in MSR_PKG_POWER_LIMIT register for PKG domain, say power_limit1/time_window1 and power_limit2/time_window2.

We just go ahead and set values in MSR_PKG_POWER_LIMIT register, after it is upto the system to determine how to use it(i.e. when/which limit).

How system is going to use it?

After enabling(with clamping) both, system power consumption will be limited between power_limit1 and power_limi2?

What is the importance time_window1 and time_window2? how it is used?

-Nobin

MSR_PKG_POWER_LIMIT

Nobin_M_
Beginner
216 Views

Processor family datasheets are much more helpfull, than system programmers manuals. Processor family datasheets has much clear documentation about RAPL.

Bernard
Black Belt
216 Views

Nobin M. wrote:

Processor family datasheets are much more helpfull, than system programmers manuals. Processor family datasheets has much clear documentation about RAPL.

Can you point to some datasheets?

Thank you in advance

Nobin_M_
Beginner
216 Views

Intel® Xeon® Processor E5-1600/E5-2600/E5-4600 Product Families Datasheets Volume One

http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e5-1600-2600-vol-1-datas...

Bernard
Black Belt
216 Views

Thank you Nobin:)

Vasileios_T_
Beginner
216 Views

Hello Martin,

I am trying to use the power governor tool on an Ivy Bridge server (Intel(R) Xeon(R) CPU E5-2680 v2), but I get:

PKG_0,Core_0,Graphics_0,Uncore_0,PKG_1,Core_1,Graphics_1,Uncore_1,
*** Error in `./power_gov': free(): invalid next size (normal): 0x0000000001d25770 ***

when I try to start the power meter.

Any ideas what could it be?

Thanks,

Vasileios.

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