All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=702246

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9Nje9QgM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9LCUtAkM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9Oz6kAoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9JfeogoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9OKypQoM,agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg9OW1yAoM


Bot(s) for this bug's original alert(s):

Atom_x64
Haswell_x64
x64

The following revision refers to this bug:
  https://chromium.googlesource.com/v8/v8.git/+/338257509d7f5ec8ea0a16ba3eb263265efa06f9

commit 338257509d7f5ec8ea0a16ba3eb263265efa06f9
Author: jgruber <jgruber@chromium.org>
Date: Fri Mar 17 12:19:29 2017

[string] Optimize ToDirectStringAssembler for sequential strings

ToDirectStringAssembler is used in StringCharCodeAt and SubString
(which uses StringCharCodeAt internally). SubString is used all over the
place (e.g. RegExp result construction), and is critical for benchmark
performance.

The CL introducing ToDirectStringAssembler caused a couple of
regressions which this is intended to fix by adding a fast path for
sequential strings.

BUG= chromium:702246 

Review-Url: https://codereview.chromium.org/2754933003
Cr-Commit-Position: refs/heads/master@{#43897}

[modify] https://crrev.com/338257509d7f5ec8ea0a16ba3eb263265efa06f9/src/code-stub-assembler.cc

This seems to have mostly recovered. Atom_x64/JetStream/base64 is still down, will keep an eye on this.