ninja-problem.md

nocc with ninja problem (and a workaround)

If you use ninja instead of make on a huge project with nocc, you would probably face an annoying problem.

As you know, the first nocc invocation starts nocc-daemon. A daemon dies in 15 seconds after nocc stops connecting (it's a heuristic that a build process has finished).

Whyever, building with ninja behaves like this:

# ninja -j 200
nocc g++ 1.cpp ...    <- starts a daemon
nocc g++ 2.cpp ...
...
nocc g++ 200.cpp ...  <- 200 parallel jobs

# !!! whyever, ninja hangs, and continues only after a daemon quits
nocc g++ 201.cpp ...  <- starts a daemon again
...
nocc g++ 400.cpp      <- 200 more parallel jobs

# ninja waits for a daemon to quit again, and so on

I don't know the actual reason. There is no similar problem with make. Probably, ninja waits not only for direct child processes (a bunch of nocc) but also for their children (nocc-daemon launched by the first nocc).

Anyway, there is a workaround: start nocc-daemon manually in advance, so that all nocc launched by ninja would connect to it.

A command-line for starting a daemon is (the same as the first nocc does):

/path/to/nocc start

and then launch your build:

ninja -j 200

If you find an easier workaround, or if you don't encounter such a problem at all, please, let me know.