On Tue, Jun 25, 2013 at 11:52:03AM -0700, Gregory Szorc wrote: > tl;dr You may experience a change in behavior in build performance > > In bug 884587, we just changed how file purging occurs during builds. > > Due to historical reasons (notably bad build dependencies and to > prevent old files from leaking into the distribution package), we > wipe out large parts of objdir/dist at the beginning of a top-level > build [1]. > > Until recently, we simply did a |rm -r| because there was no way for > the build system to know which files should or shouldn't be > retained. > The moz.build transition has given us a "whole world view" that now > allows us to identify which files should or should not belong. > Instead of performing |rm -r|, we now read in manifest files, scan > directories being purged, and selectively delete files that are > unaccounted for. > > An unfortunate side-effect of this change is that we need to walk > parts of objdir at the top of the build, which may be slow, > especially if this directory isn't in the filesystem/stat cache. > This may result in a multi-second "jank" at the beginning of the > build. Hopefully, this jank is offset by the build performing less > work (deleting fewer files at the top of the build means fewer files > need to be restored during the build). > > If you notice "unacceptable" jank during purging and you aren't > building on an SSD, please buy an SSD (if you can). I'll say it > again: *please build Firefox on an SSD if you can*. If you have an > SSD, I will be very interested in investigating further. File a new > bug that depends on bug 884587 and we'll look into things.
Alternatively, if you have plenty of RAM, build in a RAM disk. Mike _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
