On Mon, Jun 22, 2015 at 09:48:41AM -0700, Nicholas Alexander wrote: > On Sat, Jun 20, 2015 at 10:01 PM, Gregory Szorc <gsz...@mozilla.com> wrote: > > > > > > > > On Jun 20, 2015, at 20:55, Mike Hommey <m...@glandium.org> wrote: > > > > > >> On Sat, Jun 20, 2015 at 02:36:26PM -0600, Aaron Klotz wrote: > > >>> On 6/20/2015 10:20 AM, Philip Chee wrote: > > >>> Anyone want to try the same with Firefox nightly? > > >> > > >> > > >> Already did it and subsequently filed bug 873638. We can do it if we > > modify > > >> the encoding of the JS source at omnijar build time. > > >> > > >> I did some measurements last year at the 2014 JS workweek and it turns > > out > > >> that the cost of converting the omnijar's JS source to jschars during > > >> parsing is equivalent to the benefits we gain from StartupCache. > > Assuming > > >> that nothing has changed in SM with respect to the time required to do > > the > > >> conversion, if we eliminate that conversion step, we can eliminate > > >> XDR-encoded JS from the StartupCache. > > > > > > Would encoding the js files in UTF-16 eliminate the conversion step? If > > > so, we can easily do that at packaging time, although local builds would > > > not benefit from that. > > > > We could have local builds install a re-encoded file instead of doing a > > simple copy/preprocess/symlink. Might add overhead to builds and break some > > workflows where people rely on symlinks to avoid rebuilds though. I argue > > most JS developers don't care about startupcache most of the time. So no > > net win? > > > > On Android, every developer build (roughly, !MOZILLA_OFFICIAL) purges the > startup cache every time Gecko is started. See [1]. It avoids > understanding a chain of delicate dependencies from the build ID and makes > everyone's life easier. It has bitten developers trying to profile > start-up time -- we warn loudly in the logcat but it's easy to miss.
Desktop local builds do that too. Search for PURGECACHES_FILES in config/rules.mk. Mike _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
