OpenCL Instructions for Spack

docs/spack_instructions.md

@@ -27,7 +27,7 @@
 | cuda_arch     |- List of supported compute capabilities are provided [here](https://github.com/spack/spack/blob/0f271883831bec6da3fc64c92eb1805c39a9f09a/lib/spack/spack/build_systems/cuda.py#LL19C1-L47C6) <br />- Useful [link](https://arnon.dk/matching-sm-architectures-arch-and-gencode-for-various-nvidia-cards/) for matching CUDA gencodes with NVIDIA architectures| 
 |amdgpu_target| List of supported architectures are provided [here](https://github.com/spack/spack/blob/0f271883831bec6da3fc64c92eb1805c39a9f09a/lib/spack/spack/build_systems/rocm.py#LL93C1-L125C19) | 
 
-Example Commandss
+
 ```shell
 # Example 1: for Intel offload
  $ spack install babelstream%oneapi +omp 
@@ -39,3 +39,28 @@ Example Commandss
  $ spack install babelstream +omp amdgpu_target=gfx701 
 ```
 
+
+## OpenCL
+
+* There are 4 different backend options for OpenCL : AMD,CUDA,INTEL, POCL 
+* No need to specify `amdgpu_target` or `cuda_arch` here since we are using AMD and CUDA as backend respectively.
+
+
+| Flag        | Definition                      | 
+|-----------| ----------------------------------|
+| backend     | 4 different backend options: <br />- cuda <br />- amd <br />- intel <br />- pocl | 
+
+
+```shell
+# Example 1:  CUDA backend
+ $ spack install babelstream%gcc +ocl backend=cuda
+
+# Example 2:  AMD backend 
+ $ spack install babelstream%gcc +ocl backend=amd
+ 
+# Example 3:  Intel backend
+ $ spack install babelstream%gcc +ocl backend=intel
+
+# Example 4:  POCL backend
+ $ spack install babelstream%gcc +ocl backend=pocl
+```