update perf_train_cpu_many doc (#19151)

Signed-off-by: Wang, Yi A <yi.a.wang@intel.com>
Signed-off-by: Wang, Yi A <yi.a.wang@intel.com>

docs/source/en/perf_train_cpu_many.mdx

@@ -38,16 +38,30 @@ where `{pytorch_version}` should be your PyTorch version, for instance 1.12.0.
 Check more approaches for [oneccl_bind_pt installation](https://github.com/intel/torch-ccl).
 Versions of oneCCL and PyTorch must match.
 
+<Tip warning={true}>
+
+oneccl_bindings_for_pytorch 1.12.0 prebuilt wheel does not work with PyTorch 1.12.1 (it is for PyTorch 1.12.0)
+
+</Tip>
+
 ## Intel® MPI library
 Use this standards-based MPI implementation to deliver flexible, efficient, scalable cluster messaging on Intel® architecture. This component is part of the Intel® oneAPI HPC Toolkit.
-It can be installed via [MPI](https://www.intel.com/content/www/us/en/developer/articles/tool/oneapi-standalone-components.html#mpi).
 
-Please set the environment by following command before using it.
+oneccl_bindings_for_pytorch is installed along with the MPI tool set. Need to source the environment before using it.
 
+for Intel® oneCCL 1.12.0
 ```
-source /opt/intel/oneapi/setvars.sh
+oneccl_bindings_for_pytorch_path=$(python -c "from oneccl_bindings_for_pytorch import cwd; print(cwd)")
+source $oneccl_bindings_for_pytorch_path/env/setvars.sh
 ```
 
+for Intel® oneCCL whose version < 1.12.0
+```
+torch_ccl_path=$(python -c "import torch; import torch_ccl; import os;  print(os.path.abspath(os.path.dirname(torch_ccl.__file__)))")
+source $torch_ccl_path/env/setvars.sh
+```
+
+
 The following "Usage in Trainer" takes mpirun in Intel® MPI library as an example.