komake

Komake is a wrapper of make(1) that limits the concurrency of makes being recursively spawned.

Synopsis

$ komake                   # runs `make all`
$ komake -j4 myproj        # options are passsed to `make`
$ MAKE=my-make komake      # use my favorite make, wrapped by komake

Description

While working on large projects, in order to reduce build time, it is generally preferable to use the -j option so that make (1) spawns multiple sub-processes concurrently. When there are sub-projects, the main Makefile is typically written so that sub-processes, each running make (1), will be spawned for building each of those sub-projects.

The problem is that there might be a diamond dependency between those sub-projects (e.g., sub-project-1 and sub-project-2 depending on sub-project-3), and that make (1) does not have the capability to prevent the sub-project from being built simultanenously (i.e. make sub-project-3 invoked more than once). When race happens, the result of the build process becomes unpredictable, often ending up in an error.

Komake is a wrapper for make (1) that resolves this problem, by limiting the concurrency of make (1) building sub-projects to exactly one.

Setting Concurrency

In order to achieve the necessary concurrency, users are advised to set the argument of -j option to the number of CPU cores plus the number of make (1) processes that may be invoked. This is because make (1) processes being delayed due to the concurrency limitation counts towards the concurrency as well.

Notes

While komake is meant to work, Japanese users should not assume that komake is the path to victory. Read the name carefully.