On Thu, Aug 22, 2019 at 06:48:03PM -0700, Chris M. wrote: > On Mon, Aug 19, 2019 at 10:32 PM Kris Maglione <kmagli...@mozilla.com> > wrote: > > > On Tue, Aug 20, 2019 at 02:23:06PM +0900, ISHIKAWA,chiaki wrote: > > >On 2019/08/20 9:11, Dave Townsend wrote: > > >>Thanks to a tip I've tracked this down. This seems to only be the case > > when > > >>I have sccache enabled. Disabling it gives me nice quick incremental > > builds > > >>again. Of course that isn't an ideal solution but it will do for now. > > >> > > >>On Mon, Aug 19, 2019 at 1:55 PM Dave Townsend <dtowns...@mozilla.com> > > wrote: > > >> > > >>>For a couple of weeks now I've seen that any attempt to build Firefox, > > >>>even incremental builds seem to rebuild an awful lot of rust code. I > > found > > >>>this in the source which seems to suggest why: > > >>> > > https://searchfox.org/mozilla-central/source/config/makefiles/rust.mk#238. > > >>>But, this means that now an incremental build with a couple of code > > change > > >>>that have no impact on rust is taking upwards of 4 minutes to complete > > in > > >>>comparison to around 40 seconds, and the log file is full of cargo > > output. > > >>>I've heard similar comments from other developers. > > >>> > > >>>This is a pretty big increase in the time to compile and test and is > > >>>really slowing down my work. Is there any way we can avoid this? > > >>> > > >>____________________________________________ > > > > > > > > >I am using linux for local development and noticed something similar. > > > > > >So I should disable sccache (!?). > > > > For what it's worth, Rust is now configured to use incremental > > compilation, which has its own cache which isn't cleared after > > clobber, so sccache isn't actually needed anymore. Ordinary > > ccache should be sufficient. > > > sccache will still cache dependencies from crates.io. From a quick check > building the rust in the tree on my laptop, a full cache hit for rust with > sccache produces a significant speedup (2x) versus incremental alone.
I had a similar experience on a 36-core machine earlier today. It seems incremental is not working properly for the style crate: incremental is supposed to have the same effect as sccache, but it still takes a long time to compile style. I'm told mw is going to look into this in the coming weeks. In the meanwhile, as discussed on irc, it seems fair to disable CARGO_INCREMENTAL when building with sccache. Mike _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
