Compiling Julia with MKL on macOS

This was written with assumption that MKL is provided via conda. However, the same should work for standalone MKL installations with some minor tweaks.

Compiling

Create a new conda environment with mkl and set environment variables.

$ conda create -n mkl mkl -c intel
$ export MKLROOT=/usr/local/conda/envs/mkl

Clone julia repo

$ git clone https://github.com/julialang/julia

Create a Make.user file with the following contents:

USE_INTEL_MKL = 1
USE_INTEL_MKL_FFT = 1
MKLLIB = $(MKLROOT)/lib
USE_INTEL_LIBM ?= 0
USE_INTEL_JITEVENTS ?= 0
USEICC ?= 0
USEIFC ?= 0

Start compiling

make

The build will likely break with an error like

make[1]: *** [/Users/hjkim/Downloads/julia/usr/lib/julia/libmkl_rt.dylib] Error 1

Bypass this by making symlink from $MKLROOT/lib/libmkl.rt to ./usr/lib/julia

ln -s $MKLROOT/lib/libmkl.rt usr/lib/julia

Packaging

Run the Makefile under ./contrib/mac/app. To make it actually distributable, replace the symlink with a copy instead. Compiling with MARCH=haswell for my computers will help.

Issues

You may encounter an issue with Distributions.jl with something like

[ Info: Precompiling Distributions [31c24e10-a181-5473-b8eb-7969acd0382f]
ERROR: LoadError: LoadError: InitError: could not load library "/Users/hjkim/.julia/artifacts/7c9ef733699a1d86b8a6073ed08a4457e3e790f7/lib/libgfortran.5.dylib"
dlopen(/Users/hjkim/.julia/artifacts/7c9ef733699a1d86b8a6073ed08a4457e3e790f7/lib/libgfortran.5.dylib, 1): Library not loaded: @rpath/libquadmath.0.dylib
  Referenced from: /Users/hjkim/.julia/artifacts/7c9ef733699a1d86b8a6073ed08a4457e3e790f7/lib/libgfortran.5.dylib
  Reason: image not found
Stacktrace:
...

I fixed it by symlinking from my system libgfortran. /usr/local/Cellar/gcc/9.3.0_1/lib/gcc/9/libquadmath.dylib