999650 - 3% TART regression on WinXP|Linux64 on Inbound (Fx31) from bug 990336

Status: RESOLVED WONTFIX

(Core :: JavaScript Engine, defect)

Description

[Joel Maher ( :jmaher ) (UTC -8)]

on April 17th we have a TART regression on Linux64 (3.22%) and WinXP (3.64%) from the landing of this changeset:
http://hg.mozilla.org/integration/mozilla-inbound/rev/7340e1b5c7e1

Here is a graph for winxp:
http://graphs.mozilla.org/graph.html#tests=[[293,131,37]]&sel=1397665160000,1397837960000&displayrange=7&datatype=running

here is a view on tbpl to ensure it was this changeset and retriggers to ensure there isn't noise:
https://tbpl.mozilla.org/?tree=Mozilla-Inbound&fromchange=76e1244494ef&tochange=f854b5d978b5&jobname=Windows%20XP%2032-bit%20mozilla-inbound%20talos%20svgr

Here is more information about the test:
https://wiki.mozilla.org/Buildbot/Talos/Tests#TART.2FCART

Comment 1

[Joel Maher ( :jmaher ) (UTC -8)]

Terrence, can you look at this?

Comment 2

[Terrence Cole [:terrence]]

This is a backout of the same patch that caused a throughput regression last week. There is a direct tradeoff here between throughput and latency: you can't have both. I think we should take this regression instead of the other: the code that's getting removed is quick ugly and we're doing strictly less work without it.