add gcc support to offload to Intel Xeon Phi #26
Description
Using GCC on Ubuntu (Linux):
GCC (GNU Compiler Collection) does not natively support Xeon Phi in the sense of having built-in optimizations or SIMD (Single Instruction, Multiple Data) instructions specific to Xeon Phi architecture out-of-the-box. However, there are tools and compiler flags that can enable basic support for Xeon Phi processors.
How to Use Xeon Phi with GCC:
Targeting Xeon Phi (via offload): To take advantage of Xeon Phi on Ubuntu/Linux, you'll need to use the offload feature of GCC, which allows you to offload computation from the host processor (CPU) to the Xeon Phi.
The Xeon Phi supports the MIC (Many Integrated Core) architecture, which can be used via OpenMP offloading or Intel-specific compiler extensions (e.g., -xMIC-AVX512 for targeting the Xeon Phi 5100 series).
To compile programs for the Xeon Phi, you can use flags like:
-mmic: This flag tells GCC to generate code for the Xeon Phi (targeting the MIC architecture).
-march=mic: Specifies that you want to compile code for the Xeon Phi architecture.
Example:
gcc -mmic -o my_program my_program.c
This compiles my_program.c and targets it for the Xeon Phi processor.
Offload via OpenMP: You can also use OpenMP for offloading parallel workloads to the Xeon Phi. This requires using GCC with OpenMP offloading support.
Example with OpenMP:
gcc -fopenmp -mmic -o my_program my_program.c
In this case, your OpenMP parallel regions will be offloaded to the Xeon Phi, utilizing its many cores for computation.
Compiling with AVX512: The Xeon Phi 5110P supports AVX512 instructions. You can compile your code with AVX512 optimizations by using -xMIC-AVX512 (specific to the Xeon Phi architecture).
Example:
gcc -march=mic -xMIC-AVX512 -o my_program my_program.c
Limitations:
- The GCC offload model is more limited compared to Intel's tools and compilers (such as the Intel oneAPI suite).
- Performance optimizations may not be as advanced as those in Intel's own compilers (Intel ICC or oneAPI).