More readme

Author: fschlimb

examples/mlp-mpi/README.md

@@ -1,4 +1,10 @@
-# Computing a MLP sigmoid(A@B)@C on multiple ranks using MPI through MLIR
+# Computing an MLP sigmoid(A@B)@C on multiple ranks using MPI through MLIR
+
+This example shows how MLIR's sharding infrastructure can be used to distribute data and computation across multiple nodes with non-shared memory.
+
+Currently, only the lower part of the sharding pipeline is used: `shard-partition`, `convert-shard-to-mpi`, and lowering to LLVM. Therefore, the ingress MLIR is fully annotated.
+
+The example implements a "single MLP", following a 1D/2D weight-stationary partition strategy as described in figures 2a and 2b of https://arxiv.org/pdf/2211.05102.
 
 ## Prerequisites