On 2013-01-30 11:03 PM, Ehsan Akhgari wrote:
We then tried to get a sense of how much of a win the PGO optimizations are. Thanks to a series of measurements by dmandelin, we know that disabling PGO/LTCG will result in a regression of about 10-20% on benchmarks which examine DOM and layout performance such as Dromaeo and guimark2 (and 40% in one case), but no significant regressions in the startup time, and gmail interactions. Thanks to a series of telemetry measurements performed by Vladan on a Nightly build we did last week which had PGO/LTCG disabled, there are no telemetry probes which show a significant regression on builds without PGO/LTCG. Vladan is going to try to get this data out of a Tp5 run tomorrow as well, but we don't have any evidence to believe that the results of that experiments will be any different.
Vladan performed the analysis on telemetry measures reported out of a Tp5 run and the results seem to indicate that the performance of several things such as GC and CC, image decoding, page loading, session restore, search service initialization, etc. are heavily affected by turning off PGO. Please see <https://bugzilla.mozilla.org/show_bug.cgi?id=834003#c8> for the details of the measurements, but this is new evidence in favor of options #2 and #3, which unfortunately makes this a harder decision to make.
Cheers, Ehsan _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
