gecko-dev/python/mozlint
Andrew Halberstadt 529aad2e2c Bug 1430825 - [mozlint] Split work up by paths instead of by linters, r=standard8
The initial motivation for this patch, was to prevent command lines that are
too long on Windows. To that end, there is a cap to the number of paths that
can be run per job. For now that cap is set to 50. This will allow for an
average path length of 160 characters, which should be sufficient with room to
spare.

But another big benefit of this patch is that we are running more things in
parallel. Previously, mozlint ran each linter in its own subprocess, but that's
it. If running eslint is 90% of the work, it'll still only get a single
process. This means we are wasting cores as soon as the other linters are
finished.

This patch chunks the number of specified paths such that there will be N*L
jobs where 'N' is the number of cores and 'L' is the number of linters.  This
means even when there's a dominant linter, we'll be making better use of our
resources. This isn't perfect of course, as some paths might contain a small
number of files, and some will contain a very large number of files.  But it's
a start

A limitation to this approach is that if there are fewer paths specified than
there are cores, we won't schedule enough jobs per linter to use those extra
cores. One idea might be to expand specified directories and individually list
all the paths under the directory. But this has some hairy edge cases that
would be tough to catch. Doing this in a non-hacky way would also require a
medium scale refactor.

So I propose further parallelization efforts be destined for follow-ups.

MozReview-Commit-ID: JRRu13AFaii

--HG--
extra : rebase_source : 242fb71fe0af8bd2a981bd10a7216bb897fe00ac
2018-01-16 16:01:20 -05:00
..
mozlint Bug 1430825 - [mozlint] Split work up by paths instead of by linters, r=standard8 2018-01-16 16:01:20 -05:00
test Bug 1430825 - [mozlint] Split work up by paths instead of by linters, r=standard8 2018-01-16 16:01:20 -05:00
setup.py Bug 1397423 - Enable py2 linter on python/mozlint. r=ahal 2017-09-06 22:52:46 -04:00