git clone https://github.com/mmtk/mmtk-julia
git clone https://github.com/mmtk/julia
(cd julia && git checkout dev && echo 'WITH_MMTK=1' > Make.user)
export JULIA_PATH=`pwd`/julia
export MMTK_JULIA_DIR=`pwd`/mmtk-julia
(cd mmtk-julia/mmtk && cargo build --features immix --release)   # or drop "--release" for a debug build
MMTK_PLAN=Immix MMTK_BUILD=release MMTK_JULIA_DIR=`pwd`/mmtk-julia make -C julia  # or "MMTK_BUILD=debug"

If you would like debugging information in your release build of MMTk, add debug = true under [profile.release] in mmtk/Cargo.toml.

Besides checking out the binding (this repository), it is also necessary to checkout a fork containing a modified version of the Julia repository (https://github.com/mmtk/julia). Use the dev branch of the Julia repository. For example, we check out the fork as a sibling of mmtk-julia. For step-by-step instructions, read the section "Quick Building Guide".

The directory structure should look like the diagram below:

Your working directory/
├─ mmtk-julia/
│  ├─ julia/
│  └─ mmtk/
├─ julia/ (should be cloned manually)
└─ mmtk-core/ (optional)

Before building Julia, build the binding in mmtk-julia/mmtk. You must have already checked out Julia, set JULIA_PATH to point to the checkout (remember to check out the dev branch!) and set MMTK_JULIA_DIR to the binding's top-level directory.

In mmtk-core we currently support either Immix or StickyImmix implementations. Build it with cargo build --features immix or cargo build --features stickyimmix. Add --release at the end if you would like to have a release build, otherwise it is a debug build. For a release build with debugging information, first add debug = true under [profile.release] in mmtk/Cargo.toml.

To build Julia with MMTk, first ensure you have the prerequisites for building both Julia and MMTk.

Next create a Make.user file in the top-level directory of the Julia repository consisting of the line WITH_MMTK=1.

Finally, set the following environment variables:

export MMTK_BUILD=release # or debug depending on how you build the Julia binding in Rust
export MMTK_JULIA_DIR=<path-to-mmtk-julia>

... and run make.

Alternatively you can set the environment variables in your Make.user

export MMTK_BUILD := release
export MMTK_JULIA_DIR := <path-to-mmtk-julia>
export MMTK_PLAN := Immix

Currently MMTk supports a fixed heap limit or variable heap within an interval. The default is a variable heap with the minimum heap size set to Julia's default_collection_interval and the maximum size set to 70% of the free memory available. To change these values set the environment variables MMTK_MIN_HSIZE and MMTK_MAX_HSIZE to set the mininum and maximum size in megabytes, or MMTK_MIN_HSIZE_G and MMTK_MAX_HSIZE_G to set the size in gigabytes. If both environment variables are set, MMTk will use the size in megabytes. To set a fixed heap size, simply set only the variables MMTK_MAX_HSIZE or MMTK_MAX_HSIZE_G, or set MMTK_MIN_HSIZE or MMTK_MIN_HSIZE_G to 0. Note that these values can be decimal numbers, e.g. MMTK_MAX_HSIZE_G=1.5.

These environment variables are set during julia initialization time, so they can be set per-julia process.

More about MMTk: https://github.com/mmtk/mmtk-core

More about Julia: https://github.com/JuliaLang/julia