OpenMP Segmentation Fault when Targeting XE GPU

[lamb]

I am trying to find the cause of a segmentation fault when running several of the SPEC Accel OpenMP benchmarks. Specifically, I have been working with the 552.ep (embarrassingly parallel) benchmark.

OS: x86_64 GNU/Linux
CPU: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz
Accelerator: Intel Iris Xe MAX
Toolkit: Intel(R) oneAPI DPC++ Compiler 2021.1.2 (2020.10.0.1214)

Compilation commands:

$ ulimit -s unlimited
$ export IGC_EnableDPEmulation=1
$ export OverrideDefaultFP64Settings=1
$ source /opt/intel/oneapi/setvars.sh

$ icx -g -Wall -O3 -I. -fiopenmp -fopenmp-targets=spir64 *.c -o ep -lm
$ gdb ./ep

Here is the result of running gdb (run). I can install the missing debuginfos and update the question if that would help in finding a solution.

(gdb) run
Starting program: /552.pep/src/ep 
Missing separate debuginfos, use: yum debuginfo-install glibc-2.28-127.el8.x86_64
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
warning: Loadable section ".note.gnu.property" outside of ELF segments
warning: Loadable section ".note.gnu.property" outside of ELF segments
warning: Loadable section ".note.gnu.property" outside of ELF segments
[New Thread 0x155550008700 (LWP 811436)]
warning: Loadable section ".note.gnu.property" outside of ELF segments
warning: Loadable section ".note.gnu.property" outside of ELF segments
warning: Loadable section ".note.gnu.property" outside of ELF segments
warning: Loadable section ".note.gnu.property" outside of ELF segments
[New Thread 0x15554d9ac700 (LWP 811437)]
 Reading from input file ep.input


 NAS Parallel Benchmarks (NPB3.3-OPENMP-C) - EP Benchmark

 Number of random numbers generated:        67108864

Thread 1 "ep" received signal SIGSEGV, Segmentation fault.
0x000015553f455bca in vISA::G4_SrcRegRegion::computeLeftBound() () from /lib64/libigc.so.1
Missing separate debuginfos, use: yum debuginfo-install intel-gmmlib-20.4.1-i482.el8.x86_64 intel-igc-core-1.0.6410-i509.el8.x86_64 intel-igc-opencl-1.0.6410-i509.el8.x86_64 libedit-3.1-23.20170329cvs.el8.x86_64 libgcc-8.3.1-5.1.el8.x86_64 libstdc++-8.3.1-5.1.el8.x86_64 libxml2-2.9.7-8.el8.x86_64 ncurses-libs-6.1-7.20180224.el8.x86_64 xz-libs-5.2.4-3.el8.x86_64

Also, I'm intending to use the level0 backend, but I see "OpenCLProgramContext" in the gdb output. Does this mean I may be using the OpenCL backend by mistake?

Thank you!

[Vinutha_SV]

Hi,

Can you try this export setting for L0. export SYCL_DEVICE_FILTER=level_zero if you are using 2021.2 compiler. For older compiler export SYCL_BE=level_zero?

[Vinutha_SV]

Hi,

I hope your issue is resolved. We will stop monitoring this thread.