perf_event_paranoid setting

[youn__kihang]

Hi all,

I have got a  warning message in vtune profiling.
"amplxe: Warning: Only user space will be profiled due to credentials lack. Consider changing /proc/sys/kernel/perf_event_paranoid file for enabling kernel space profiling."
and current "perf_event_paranoid" is 2.

I would like to use the options including hotspots and hpc-performance in Vtune profiler, Advisor and Tracer.
In the current situation, Are there any methods to use the profiler without changing the "perf_event_paranoid" file?
Because I am not an administrator of whole systems, I can't modify the files.
To ask the administrator, I need solid evidence to modify the file. Is there any document containing the recommended option about "perf_event_paranoid".
Also, In my case, what is the recommended value (0 or 1)?

Thank you in advance.

[ChithraJ_Intel · Accepted solution]

Hi,

Thanks for reaching out to us. 
Perf-based driverless collection can be used for running Advanced Hotspots, General Exploration and Custom event-based sampling analysis types on Linux and Android OS. If the uncore events support is available on the system, the VTune Amplifier may also use the Perf collection for Memory Access, HPC Performance Characterization and General Exploration analysis types with the Analyze memory bandwidth option enabled.To enable the Perf driverless collection to match all the hardware profiling functionality provided with Intel drivers, you will need administrative privileges to configure system options.So, in your case, you can try setting /proc/sys/kernel/perf_event_paranoid value equal to 1 for getting kernel profiling data.

VTune Amplifier can use the driverless Perf-based collection if the following requirements are satisfied:

• Your system is based on kernel 2.6.32 or higher, which exports CPU PMU programming details over /sys/bus/event_source/devices/cpu/format file system.
• Perf utility is available on the system and enabled in the kernel.
• Uncore events support is available on your system. To check, make sure uncore_* devices are available in the /sys/bus/event_source/devices folder.

For more information on perf driverless collection, refer to:

https://software.intel.com/content/www/us/en/develop/documentation/vtune-cookbook/top/configuration-recipes/profiling-hardware-without-sampling-drivers.html

https://scc.ustc.edu.cn/zlsc/tc4600/intel/2017.0.098/vtune_amplifier_xe/help/GUID-FA9ECB1B-C58E-47DF-9684-0E644DAD0CA9.html

Please refer to https://www.kernel.org/doc/html/latest/admin-guide/perf-security.html for getting more about perf_event_paranoid setting.

[youn__kihang]

Hi Chithra,

Thank you for your answer.
As you said, setting perf_event_paranoid value equal to 1 works well.
If I have any other questions, I will contact the forum.

Best Regrads,
Kihang

[ChithraJ_Intel]

Hi Kihang,

Glad to know that the solution worked for you.

We are closing the case now. Please feel free to reach out to us if you have any issues.

Thanks.