All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=738839

Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?keys=agxzfmNocm9tZXBlcmZyFAsSB0Fub21hbHkYgIDg1vbAuQkM


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

webrtc-linux-large-tests

https://chromium.googlesource.com/external/webrtc/+/36b1a5fcec6270ec4a5bea87b33a49b418a3cb29 seems to be a culprit. 

all the alerts for a bug: https://chromeperf.appspot.com/group_report?bug_id=738839

Updated  crbug.com/738852 , most likely same cause.

The following revision refers to this bug:
  https://chromium.googlesource.com/external/webrtc.git/+/3ffa72d0f03b75812c0ce367c1958ff9a80a6aeb

commit 3ffa72d0f03b75812c0ce367c1958ff9a80a6aeb
Author: Jonathan Yu <yujo@chromium.org>
Date: Sat Jul 08 23:36:26 2017

Add AudioFrame::ResetWithoutMuting() to address performance regression.

Prior to https://codereview.webrtc.org/2750783004/ Reset() intentionally
did not zero out the buffer. After that change, callers calling Reset()
and then mutable_data() were performing a wasteful zeroing.

This change adds ResetWithoutMuting() to match the old behavior and
switches the sole non-test caller of Reset() to use ResetWithoutMuting()
instead.

Prior to this change (optimized, Linux):
$ out/Default/webrtc_perf_tests --gtest_filter=NetEqPerformanceTest.Run* \
  --gtest_repeat=10 | grep neteq_performance
*RESULT neteq_performance: 10_pl_10_drift= 4051 ms
*RESULT neteq_performance: 0_pl_0_drift= 1768 ms
*RESULT neteq_performance: 10_pl_10_drift= 3666 ms
*RESULT neteq_performance: 0_pl_0_drift= 1690 ms
*RESULT neteq_performance: 10_pl_10_drift= 3685 ms
*RESULT neteq_performance: 0_pl_0_drift= 1693 ms
*RESULT neteq_performance: 10_pl_10_drift= 3720 ms
*RESULT neteq_performance: 0_pl_0_drift= 1690 ms
*RESULT neteq_performance: 10_pl_10_drift= 3780 ms
*RESULT neteq_performance: 0_pl_0_drift= 1728 ms
*RESULT neteq_performance: 10_pl_10_drift= 3733 ms
*RESULT neteq_performance: 0_pl_0_drift= 1737 ms
*RESULT neteq_performance: 10_pl_10_drift= 3781 ms
*RESULT neteq_performance: 0_pl_0_drift= 1744 ms
*RESULT neteq_performance: 10_pl_10_drift= 3712 ms
*RESULT neteq_performance: 0_pl_0_drift= 1731 ms
*RESULT neteq_performance: 10_pl_10_drift= 3681 ms
*RESULT neteq_performance: 0_pl_0_drift= 1691 ms
*RESULT neteq_performance: 10_pl_10_drift= 3681 ms
*RESULT neteq_performance: 0_pl_0_drift= 1690 ms

With this change:
$ out/Default/webrtc_perf_tests --gtest_filter=NetEqPerformanceTest.Run* \
  --gtest_repeat=10 | grep neteq_performance
*RESULT neteq_performance: 10_pl_10_drift= 3824 ms
*RESULT neteq_performance: 0_pl_0_drift= 1632 ms
*RESULT neteq_performance: 10_pl_10_drift= 3502 ms
*RESULT neteq_performance: 0_pl_0_drift= 1521 ms
*RESULT neteq_performance: 10_pl_10_drift= 3520 ms
*RESULT neteq_performance: 0_pl_0_drift= 1534 ms
*RESULT neteq_performance: 10_pl_10_drift= 3517 ms
*RESULT neteq_performance: 0_pl_0_drift= 1530 ms
*RESULT neteq_performance: 10_pl_10_drift= 3521 ms
*RESULT neteq_performance: 0_pl_0_drift= 1527 ms
*RESULT neteq_performance: 10_pl_10_drift= 3511 ms
*RESULT neteq_performance: 0_pl_0_drift= 1533 ms
*RESULT neteq_performance: 10_pl_10_drift= 3518 ms
*RESULT neteq_performance: 0_pl_0_drift= 1523 ms
*RESULT neteq_performance: 10_pl_10_drift= 3503 ms
*RESULT neteq_performance: 0_pl_0_drift= 1524 ms
*RESULT neteq_performance: 10_pl_10_drift= 3514 ms
*RESULT neteq_performance: 0_pl_0_drift= 1534 ms
*RESULT neteq_performance: 10_pl_10_drift= 3501 ms
*RESULT neteq_performance: 0_pl_0_drift= 1530 ms

BUG= webrtc:7343 , chromium:738852 , chromium:738839 

Change-Id: Idcbb276ca0ed27fff95164a73f1c1fa310175ee5
Reviewed-on: https://chromium-review.googlesource.com/563021
Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org>
Reviewed-by: Olga Sharonova <olka@webrtc.org>
Reviewed-by: Tommi <tommi@webrtc.org>
Commit-Queue: Tommi <tommi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#18939}
[modify] https://crrev.com/3ffa72d0f03b75812c0ce367c1958ff9a80a6aeb/webrtc/modules/audio_coding/neteq/sync_buffer.cc
[modify] https://crrev.com/3ffa72d0f03b75812c0ce367c1958ff9a80a6aeb/webrtc/modules/include/module_common_types.h

Graphs are back down to prior levels, marking fixed

\o/ thanks!