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
2fc46e1871 broke running ./git-annex test
when git-annex-shell is not in PATH from another install, and also
caused the wrong git-annex-shell to be tested.
Using a symlink made programPath return the .cabal/ directory where the
git-annex binary is, but git-annex-shell is not in that directory.
Changing to a hard link avoids that problem.
Sponsored-by: Dartmouth College's Datalad project
