Community
cancel
Showing results for 
Search instead for 
Did you mean: 
raoufeh
Beginner
46 Views

Intel PCM and CPU hotplug Issue

Hi all,

I was using the Intel PCM in an 8 core (SMT-16thread) Intel server and it was doing fine. Recently, I needed to run my experiments while diableing some cores using CPU hotplug capability of Linux (http://www.cyberciti.biz/faq/debian-rhel-centos-redhat-suse-hotplug-cpu/)

But when I try to run the PCM while some of the cores are disabled I get the following error:

Can not access CPUs Model Specific Registers (MSRs).
Try to execute 'modprobe msr' as root user and then
you also must have read and write permissions for /dev/cpu/*/msr devices (the 'chown' command can help).

Nothing has changed in the system in terms of permission and the msr module is added using modprobe. So I guess PCM tries to access the folders for diabled cores in /dev/cpu/* and since hotplug removes the folder for the diabled cores, this error is generated.

I was wondering if there is a way to solve this problem? or if the developers are aware of this issue?


Thanks,
Cheers,
RSH
0 Kudos
1 Reply
Roman_D_Intel
Employee
46 Views

Hi RSH,

thanks for reporting this. So far we did not look at the systems with cores disabled by OS. We shouldfind outhow we can prioritize this requestto find a simple solution for such configurations.

Thanks,
Roman