All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=830658

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=1e9dee393108b74876e4ff8f4ffd87f46927ff64e8059c9d4787ae0c816e8bc4


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

chromium-rel-mac11-pro
chromium-rel-mac12
chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia
chromium-rel-win7-x64-dual
chromium-rel-win8-dual
linux-release

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/12f5012cc40000

📍 Found significant differences after each of 2 commits.
https://pinpoint-dot-chromeperf.appspot.com/job/12f5012cc40000

[runtime] Do some more StringTable shrinking by cbruni@chromium.org
https://chromium.googlesource.com/v8/v8/+/6823c0a496a75161e3a82eefc759180b547077e2

[reland] [in-place weak refs] Replace the WeakCell potentially in Map::raw_transitions_. by marja@chromium.org
https://chromium.googlesource.com/v8/v8/+/ceaf02d6138e329560e831265a4391deb7bea7df

Understanding performance regressions:
  http://g.co/ChromePerformanceRegressions

The main regression point is the stringtable commit from cbruni@.

Looking at this:

https://chromeperf.appspot.com/group_report?sid=1e9dee393108b74876e4ff8f4ffd87f46927ff64e8059c9d4787ae0c816e8bc4

it's still too early to say whether the revert fixed (nearly) all of the performance issue and how much remains. For most graphs, the new value is within the noise compared to the old values (before cbruni@'s orig commit).

I'll check the situation again once we get a couple of more runs.

Checked some graphs (there are too much to go through by hand):

Bounced back (at least based on visual inspection):

https://chromeperf.appspot.com/report?sid=8d105dc27749aabc0afa5b9e71b5ed93de86690d00a0a11c13c3be75d51c8c75&rev=548689

https://chromeperf.appspot.com/report?sid=c5bbbacc4419e0ac97818220ee7aa388aa18b4ee97aa473eb22cdbd3c03b08bf&rev=548702

https://chromeperf.appspot.com/report?sid=2d27d38df2a96d61404c179c0b91c35d7bdc03c23b7c6421506b87414c4dd784&rev=548702

https://chromeperf.appspot.com/report?sid=9acee8e72c5a8695b3261c71f2947f7588121f7e6e1411bb4a14635b624be945&rev=548702

https://chromeperf.appspot.com/report?sid=accf6fdd4de2d725a393974ee021d45a864d0dd0a8960bb29dc171a2cf669c2f&rev=548689


Based on unscientific extrapolating, assuming the revert indeed fixed everything, mostly, and my commit is not relevant.