MLton 20210117

# RunningOnNetBSD

MLton runs fine on NetBSD.

## Installing the correct packages for NetBSD

The NetBSD system installs 3rd party packages by a mechanism known as pkgsrc. This is a tree of Makefiles which when invoked downloads the source code, builds a package and installs it on the system. In order to run MLton on NetBSD, you will have to install several packages for it to work:

- shells/bash

- devel/gmp

- devel/gmake

In order to get graphical call-graphs of profiling information, you will need the additional package

- graphics/graphviz

To build the documentation for MLton, you will need the addtional package

- textproc/asciidoc.

## Tips for compiling and using MLton on NetBSD

MLton can be a memory-hog on computers with little memory. While 640Mb of RAM ought to be enough to self-compile MLton one might want to do some tuning to the NetBSD VM subsystem in order to succeed. The notes presented here is what JesperLouisAndersen uses for compiling MLton on his laptop.

### The NetBSD VM subsystem

NetBSD uses a VM subsystem named UVM. Tuning the VM system can be done via the sysctl(8)-interface with the "VM" MIB set.

### Tuning the NetBSD VM subsystem for MLton

MLton uses a lot of anonymous pages when it is running. Thus, we will need to tune up the default of 80 for anonymous pages. Setting

    sysctl -w vm.anonmax=95
    sysctl -w vm.anonmin=50
    sysctl -w vm.filemin=2
    sysctl -w vm.execmin=2
    sysctl -w vm.filemax=4
    sysctl -w vm.execmax=4

makes it less likely for the VM system to swap out anonymous pages. For a full explanation of the above flags, see the documentation.

The result is that my laptop goes from a MLton compile where it swaps a lot to a MLton compile with no swapping.