On Thu, Jul 20, 2017 at 9:33 AM, James Graham <ja...@hoppipolla.co.uk> wrote:
> Bug 1341078 and dependencies just landed on inbound, which means we now > have the W3C/web-platform-tests CSS tests in-tree and running in > automation. This adds about 12,000 reftests for CSS features to the > web-platform-tests suite. They are currently enabled in CI, but only on > linux*, due to limited capacity on OSX, and issues with the harness on > Windows. The tests will be enabled on other platforms once these problems > are resolved. > > Servo was already running many of these tests in their automation, so this > landing plugs a gap in the stylo testing vs upstream. > > Note that, as usual with wpt landings, these tests have been vetted for > stability, but not for the actual results. > > Changes to the css tests in this directory will be upstreamed to > web-platform-tests in the same way as for any other web-platform-test. Note > that the reftest harness versions of the Mozilla submitted tests are still > running, so if you want to edit or add to those it is recommended to use > the copy in layout/reftests/w3c-css/submitted/ since that will be > correctly synchronised and currently runs on more platforms in CI. > > The number of tests and nature of reftests means that this change added a > large number of files to the repository (around 37,000). Apologies for any > inconvenience caused by such a large changeset. I'm told that narrow clones > are just around the corner and may make this kind of thing more tolerable > in the future. > "Around the corner" is a bit optimistic. Mercurial 4.3 has experimental support for sparse checkouts via an extension. (The feature has been part of a Facebook extension for years.) I plan to leverage this in automation to speed up VCS interactions. But end-user support will likely be experimental until the feature stabilizes upstream, hopefully in 4.4 in 3 months. In the mean time, be sure to install Watchman (https://facebook.github.io/ watchman/) and the fsmonitor Mercurial extension to make operations faster. `mach mercurial-setup` should help with this. Git doesn't yet have filesystem watcher integration, so you are pretty much at the mercy of your filesystem and I/O subsystem. However, an engineer at Twitter is currently trying to land Watchman support into the upstream Git project! The first version of the patches was emailed in March. The 14th iteration was emailed last week. But there still appears to be active discussion on some high-level details of the patch series. So I'm not holding my breath waiting for it to land. For reference, the best timings I could obtain are as follows. These are under ideal conditions with as much as possible already in filesystem caches. If you actually need to perform I/O due to a cache miss (which is pretty common because common build system activity touches tons of files and tends to cause cache eviction), the differences with Watchman are even more pronounced. So it isn't uncommon for Watchman to save a second or two for random operations. <before CSS WPT landing> Linux $ hg status no watchman: ~1.00s w/ watchman: ~0.11s $ git status ~0.28s MacOS $ hg status no watchman: ~1.78s w/ watchman: ~0.23s Windows $ hg status no watchman: ~2.31s w/ watchman: ~0.35s <after CSS WPT landing> Linux $ hg status no watchman: ~1.16s w/ watchman: ~0.12s $ git status ~0.33s MacOS $ hg status no watchman: ~2.04s w/ watchman: ~0.26s Windows $ hg status no watchman: ~2.56s w/ watchman: ~0.40s _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
