topic Hi Alex, in Intel® oneAPI Math Kernel Library

Linux setcap and MKL

Barry__Alex — Fri, 11 Aug 2017 17:16:23 GMT

I have a program using MKL on Linux (Centos 7.3 1611) that runs fine without any setcap capabilities. I would like to adjust thread priorities, so I added CAP_SYS_NICE using setcap. When I run the program, it starts fine. As soon as it tries to run any MKL functions, it fails with an error saying it failed to load mkl_loader. The program runs fine as root with CAP_SYS_NICE set. I have googled around, and have not found a solution that works yet.

"error saying it failed to

Gennady_F_Intel — Sat, 12 Aug 2017 05:09:04 GMT

"error saying it failed to load mkl_loader". Alex, what is the full message do you see?

Hi Alex,

Evarist_F_Intel — Sat, 12 Aug 2017 05:29:10 GMT

Hi Alex,

I second Gennady's question.

If I understand things right you run the application with root privileges. Could you please confirm the application works fine if you simply run it with root privileges, but w/o any setcap stuff?

If yes, could you please try running your application with

LD_DEBUG=libs

and look for a hint why it can't load mkl_loader or put the trace here?

Sorry to put this question on

Barry__Alex — Thu, 31 May 2018 22:53:32 GMT

Sorry to put this question on hold for so long, but project priorities changed...

The exact error message I get is:

Intel MKL FATAL ERROR: Cannot load <mkl-loader>.

I get this when I run the program (linked to MKL, Linux, x64) as a standard user with CAP_SYS_NICE set. With CAP_SYS_NICE not set, a call to change the scheduler priority (to SCHED_FIFO in a different thread) and policy fails, but MKL still loads. The goal is to get it to run as a standard user, be able to change priority and use MKL.

The kernel version was 3.10.0-514.6.1.el7.x86_64. I tried this exact same program on a Fedora 27 install using a 4.13 kernel, and I had no problems loading MKL, with or without CAP_SYS_NICE set.

Running the program as root allows the program to run with CAP_SYS_NICE set. It is not desirable to run as root permanently.