On Wed, Oct 17, 2012 at 06:55:57PM -0700, Dave Mandelin wrote: > Following the recent discussion about PGO, I really wanted to understand what > benefits PGO gives Firefox on Windows, if any--I was skeptical. Rafael (IIRC) > posted some Talos numbers, but I didn't know how to interpret them. So I > decided to try a few simple experiments to try to falsify the hypothesis that > "PGO has user-perceivable benefits". > > Experimental setup: Windows builds from > http://hg.mozilla.org/mozilla-central/rev/5f4a6a474455 on a Windows 7 Xeon. I > took opt and pgo builds from the tbpl links. > > Experiment 1: cold startup time > > I used a camera to measure time from pressing enter on a > a command line until the Fx window was completely shown. > > results: > opt: 3.025 seconds > pgo: 1.841 > > - A clear win for PGO. I'm told that there is a startup > time optimization that orders omni.ja that only runs > in PGO builds. So it's not necessarily from the PGO > itself, but at least it means the current PGO builds > really are better.
If you copy omni.ja from the PGO build to the opt build, you'll be able to see if everything comes from that. We're planning to make that currently PGO-only optimization run on all builds. (bug 773171) Mike _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
