Default to the number of CPU cores, which seems about optimal
on my laptop. Using one more saves me 2 seconds actually.
Better packing of workers improves speed significantly.
In 2 tests runs, I saw segfaulting workers despite my attempt
to work around that issue. So detect when a worker does, and re-run it.
Removed installSignalHandlers again, because I was seeing an
error "lost signal due to full pipe", which I guess was somehow caused
by using it.
Sponsored-by: Dartmouth College's Datalad project
Using concurrent-output this is easy. Just have to check if tasty has
color enabled, and propagate it into the worker processes, some of which
will be run without a controlling console.
Also added a call to installSignalHandlers; I noticed that interrupting
the test suite could leave the console in a bad state and this fixes
that.
The ansi-terminal dependency is free, since tasty also depends on it.
Sponsored-by: Dartmouth College's Datalad project
Unit tests are the main bulk of runtime, so splitting them into 2 or 3
parts should help.
For now, the number of parts is still 1, because on my 4 core laptop,
2 was a little bit slower, and 3 slower yet. However, this probably does
vary based on the number of cores, so needs to be revisited, and perhaps
made dynamic.
Since each test mode gets split into the specified number of parts,
plus property and remote tests, 2 gives 8 parts, and 3 gives 11 parts.
Load went to maybe 18, so there was probably contention slowing things
down.
So probably it needs to start N workers with some parts, and when a
worker finishes, run it with the next part, until all parts are
processed.
Sponsored-by: Dartmouth College's Datalad project
Note the very weird workaround for what appears to be some kind of tasty
bug, which causes a segfault. This is not new to this modification,
I was seeing a segfault before at least intermittently when limiting
git-annex test -p to only run a single test group.
Also, the path from one test repo to a remote test repo used to be
"../../foo", which somehow broke when moving the test repos from .t to
.t/N. I don't actually quite understand how it used to work, but
"../foo" seems correct and works in the new situation.
Test output from the concurrent processes is not yet serialized.
Should be easy to do using concurrent-output.
More test groups will probably make the speedup larger. It would
probably be best to have a larger number of test groups and divvy them
amoung subprocesses numbered based on the number of CPU cores, perhaps
times 2 or 3.
Sponsored-by: Dartmouth College's Datalad project
