update README

Author: vchuravy

README.md

@@ -1 +1,32 @@
-# LIKWID.jl
+LIKWID.jl
+=========
+*Like I Knew What I am Doing*
+
+LIKWID.jl is a Julia wrapper for [LIKWID](https://github.com/RRZE-HPC/likwid).
+
+Installation
+------------
+
+First install `likwid` following https://github.com/RRZE-HPC/likwid#download-build-and-install,
+and then use the Julia package manger to install `]add https://github.com/JuliaPerf/LIKWID.jl`.
+
+Example
+-------
+
+```julia
+using LIKWID
+using LinearAlgebra
+
+A = rand(128, 64)
+B = rand(64, 128)
+C = zeros(128, 128)
+
+LIKWID.Marker.startregion("matmul")
+mul!(C, A, B)
+LIKWID.Marker.stopregion("matmul")
+```
+
+License
+-------
+
+LIKWID.jl is licensed under the [MIT license](LICENSE).