Xeon Phi COREFREQ register

[Yuji_S_]

Hi,

I tried to read a SBox MMIO register of COREFREQ (address offset = 0x4100) to get current CPU frequency of Xeon Phi and the value obtained was 0x80010416. How can I  get current CPU frequency from the value of COREFREQ register?

[Loc_N_Intel]

Hello,

Let me investigate your question and get back to you soon. Thank you.

[Loc_N_Intel]

Hello Yuji,

If you want to retrieve the information of the Intel(R) Xeon Phi(TM), you may use the MicAccessAPI interface. See Section 5.2 of the document "Intel(R) Xeon Phi(TM) Coprocessor System Software Developers Guide" (go to http://software.intel.com/mic-developer and click on "PROGRAMMING" tab . Among these APIs, there is one API called MicGetFrequency allows user to get the current frequency for either the CORE or the GDDR.

MicAccessAPI can be found in /opt/intel/mic/sysmgmt. Examples on using MicAccessAPI can be found in /opt/intel/mic/sysmgmt/sdk/Examples/Usage.

Thank you.

[Yuji_S_]

Thank you.

MicAccessAPI can be used in HOST according to figure 5-2 in the System Software Developers Guide. Can I provide software on Xeon Phi with the current CORE frequency directly (without using MPSS if possible)?

[Loc_N_Intel]

Hi Yuji,

On Xeon Phi(TM), you just simply read the value associated with the "cpu MHz" field in the file /proc/cpuinfo .  

[Sameer_A_]

loc-nguyen (Intel) wrote:

Hello Yuji,

If you want to retrieve the information of the Intel(R) Xeon Phi(TM), you may use the MicAccessAPI interface. See Section 5.2 of the document "Intel(R) Xeon Phi(TM) Coprocessor System Software Developers Guide" (go to http://software.intel.com/mic-developer and click on "PROGRAMMING" tab . Among these APIs, there is one API called MicGetFrequency allows user to get the current frequency for either the CORE or the GDDR.

MicAccessAPI can be found in /opt/intel/mic/sysmgmt. Examples on using MicAccessAPI can be found in /opt/intel/mic/sysmgmt/sdk/Examples/Usage.

Thank you.

Is there a specific package separate from MPSS I need to install to get the micmgmt/sdk installed? I don't have the directory 
/opt/intel/mic/sysmgmt in my installation . 

[JJK]

According to the "Intel(R) Xeon Phi(TM) Coprocessor System Software Developers Guide":

The MIC Management Library (libmicmgmt) supersedes MicAccessAPI which was available with previous releases of the software stack. MicAccessAPI is deprecated on Linux as of MPSS 2.1.6720 and on Windows as of MPSS 3.2.
Libmicmgmt is a C/C++ library that exposes a set of APIs for applications to monitor and configure several metrics of the Intel® Xeon Phi™ coprocessor platform.

Thus, you need to have the libmgmt packages installed, most notably glibc2.12.2pkg-libmicmgmt-doc-3.4.4-1.glibc2.12.2.x86_64.rpm . There's an example installed with that package in /usr/share/doc/micmgmt/examples/examples.c which should provide you with all the right info (NOTE: this sample code needs to be run as root!)

[Sameer_A_]

JJK wrote:

According to the "Intel(R) Xeon Phi(TM) Coprocessor System Software Developers Guide":

The MIC Management Library (libmicmgmt) supersedes MicAccessAPI which was available with previous releases of the software stack. MicAccessAPI is deprecated on Linux as of MPSS 2.1.6720 and on Windows as of MPSS 3.2.
Libmicmgmt is a C/C++ library that exposes a set of APIs for applications to monitor and configure several metrics of the Intel® Xeon Phi™ coprocessor platform.

Thus, you need to have the libmgmt packages installed, most notably glibc2.12.2pkg-libmicmgmt-doc-3.4.4-1.glibc2.12.2.x86_64.rpm . There's an example installed with that package in /usr/share/doc/micmgmt/examples/examples.c which should provide you with all the right info (NOTE: this sample code needs to be run as root!

Thank you for the timely response. That explains why I had that directory before but not after I updated my MPSS then. I am surprised the PAPI still uses the MICAccessSDK in their 5.4.1 implementation that shipped March 2015. 

Thanks!

[Sameer_A_]

JJK, 

Any idea why the library libMicAccessSDK is still present and ships with newer MPSS versions?

The programming guide lists it in a diagram page 46, I just don't understand how programmers can compile for it if the  header files are not present.

[JJK]

I'm not the expert here, nor an Intel representative but my guess is that the old libMicAccessSDK.so files are still shipped to ensure that programs compiled using the now deprecated mpss 2.1 stack continue to function.

As for PAPI: my bet is that the PAPI developers are not (yet) aware that they need to update their code to use the newer library.

Hopefully someone from Intel will correct me if I am wrong :)