All graphs for this bug:
  https://chromeperf.appspot.com/group_report?bug_id=785578

(For debugging:) Original alerts at time of bug-filing:
  https://chromeperf.appspot.com/group_report?sid=1da0b6b2d4cd15e39e37bbaed58f23f5bd7912b4c8033d71939060c8a3886e15


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

android-nexus5X
android-nexus6
android-webview-nexus5X
android-webview-nexus6
chromium-rel-mac-retina
chromium-rel-mac11
chromium-rel-mac11-air
chromium-rel-mac11-pro
chromium-rel-win10
chromium-rel-win7-dual
chromium-rel-win7-gpu-ati
chromium-rel-win7-gpu-intel
chromium-rel-win7-gpu-nvidia
chromium-rel-win7-x64-dual
chromium-rel-win8-dual
linux-release
win-high-dpi

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14f556c5f80000

📍 Couldn't reproduce a difference.
https://pinpoint-dot-chromeperf.appspot.com/job/14f556c5f80000

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8962733454617451488

=== BISECT JOB RESULTS ===
Perf regression found but unable to continue

Bisect was stopped because a commit couldn't be classified as either
good or bad.


Bisect Details
  Configuration: winx64nvidia_perf_bisect
  Benchmark    : blink_perf.owp_storage
  Metric       : idb-load-docs/idb-load-docs


Please refer to the following doc on diagnosing blink_perf regressions:
  https://chromium.googlesource.com/chromium/src/+/master/docs/speed/benchmark_harnesses/blink_perf.md

To Run This Test
  src/tools/perf/run_benchmark -v --browser=release_x64 --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.owp_storage

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8962733454617451488


For feedback, file a bug with component Speed>Bisection

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/14dbbf35f80000

📍 Couldn't reproduce a difference.
https://pinpoint-dot-chromeperf.appspot.com/job/14dbbf35f80000

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8962277794315989520

=== BISECT JOB RESULTS ===
Bisect failed for unknown reasons

Please contact the team (see below) and report the error.


Bisect Details
  Configuration: android_nexus5_perf_bisect
  Benchmark    : blink_perf.owp_storage
  Metric       : IndexedDBTransaction::lifetime/IndexedDBTransaction::lifetime


Please refer to the following doc on diagnosing blink_perf regressions:
  https://chromium.googlesource.com/chromium/src/+/master/docs/speed/benchmark_harnesses/blink_perf.md

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-chromium --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.owp_storage

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8962277794315989520


For feedback, file a bug with component Speed>Bisection

📍 Pinpoint job started.
https://pinpoint-dot-chromeperf.appspot.com/job/12aff8cff80000

📍 Couldn't reproduce a difference.
https://pinpoint-dot-chromeperf.appspot.com/job/12aff8cff80000

Started bisect job https://chromeperf.appspot.com/buildbucket_job_status/8960846494338790544

=== Auto-CCing suspected CL author pwnall@chromium.org ===

Hi pwnall@chromium.org, the bisect results pointed to your CL, please take a look at the
results.


=== BISECT JOB RESULTS ===
Perf regression found with culprit

Suspected Commit
  Author : Victor Costan
  Commit : 564f38984a515998699c7a522f9721a22933630c
  Date   : Tue Nov 14 00:59:39 2017
  Subject: IndexedDB: Re-enable special handling of large values.

Bisect Details
  Configuration: android_webview_nexus6_aosp_perf_bisect
  Benchmark    : blink_perf.owp_storage
  Metric       : IndexedDBTransaction::lifetime/IndexedDBTransaction::lifetime
  Change       : 20.87% | 118.488116667 -> 143.2114

Revision             Result                  N
chromium@516042      118.488 +- 8.84004      6      good
chromium@516118      119.978 +- 6.60365      6      good
chromium@516123      121.131 +- 5.95058      6      good
chromium@516125      120.486 +- 5.71296      6      good
chromium@516126      144.36 +- 7.23389       6      bad       <--
chromium@516128      142.234 +- 4.06589      6      bad
chromium@516137      144.473 +- 2.13771      6      bad
chromium@516156      140.773 +- 3.57576      6      bad
chromium@516193      143.211 +- 5.71864      6      bad

Please refer to the following doc on diagnosing blink_perf regressions:
  https://chromium.googlesource.com/chromium/src/+/master/docs/speed/benchmark_harnesses/blink_perf.md

To Run This Test
  src/tools/perf/run_benchmark -v --browser=android-webview --output-format=chartjson --upload-results --pageset-repeat=1 --also-run-disabled-tests blink_perf.owp_storage

More information on addressing performance regressions:
  http://g.co/ChromePerformanceRegressions

Debug information about this bisect:
  https://chromeperf.appspot.com/buildbucket_job_status/8960846494338790544


For feedback, file a bug with component Speed>Bisection

I don't really know what to say here.  Issue 759589  claimed a performance regression when large value wrapping got disabled in https://crrev.com/c/621394

This issue points to https://crrev.com/c/765057 which is effectively a revert of https://crrev.com/c/621394 -- I probably should've called it just that.

Either the perf tests are unreliable, or Blob handling has changed significantly (mojofication?) between https://crrev.com/c/621394 (#496648 on master) and https://crrev.com/c/765057 (#516126 on master).

dmurph@, jsbell@: cc-ed you in case you have any opinions on this.