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Issue 794718 link

Starred by 1 user
Status: Fixed
Owner:
xingliu@chromium.org
Closed: Jan 2018
Cc:
qin...@chromium.org
dtrainor@chromium.org
Components:
EstimatedDays: ----
NextAction: ----
OS: Android
Pri: 3
Type: Bug


Participants' hotlists:
Parallel-Download-Follow-Ups


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Parallel download Finch experiment group may compare different sample sets.

Project Member Reported by xingliu@chromium.org, Dec 13 2017 
Currently we have an issue that the Control group always read the
default configuration of parallel download defined in the code.

However, when tweaking the server config, we can use different slice
size, which will result in experiment groups comparing different sample
sets and undermine the credibility of metrics.

For example, ThreeRequestEnabled group use 1.33MB as min slice size, then it compares with control group which read default min slice size of 2MB from code. Then files from 1.33MB to 2MB is not in control group but belongs to ThreeRequestEnabled group.

We can add a finch parameter to disable parallel download while the feature is enabled. In this way, we can create a control group that enabled the feature and get the configuration and disable parallel download in the same time.
Project Member

Comment 1 by bugdroid1@chromium.org, Dec 14 2017 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/d4a6ed24f0e825eef903ecfc6b2fd673eb710f96

commit d4a6ed24f0e825eef903ecfc6b2fd673eb710f96
Author: Xing Liu <xingliu@chromium.org>
Date: Thu Dec 14 17:52:01 2017

Parallel download: Add a Finch parameter for future experiment.

Currently we have an issue that the Control group always read the
default configuration of parallel download defined in the code.

However, when tweaking the server config, we can use different slice
size, which will result in experiment groups comparing different sample
sets.

This CL adds a Finch parameter to alternatively disable parallel
download in an enable experiment group, and also read configs from
the server.


Bug:  794718 
Change-Id: I9cf91233cbaf3dd22917af2e026c736803bd8e19
Reviewed-on: https://chromium-review.googlesource.com/825984
Commit-Queue: Xing Liu <xingliu@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Cr-Commit-Position: refs/heads/master@{#524109}
[modify] https://crrev.com/d4a6ed24f0e825eef903ecfc6b2fd673eb710f96/content/browser/download/parallel_download_utils.cc
[modify] https://crrev.com/d4a6ed24f0e825eef903ecfc6b2fd673eb710f96/content/browser/download/parallel_download_utils.h
[modify] https://crrev.com/d4a6ed24f0e825eef903ecfc6b2fd673eb710f96/content/browser/download/parallel_download_utils_unittest.cc

Comment 2 by xingliu@chromium.org, Jan 10 2018 

This may need a new finch experiment on M65, probably on beta channel only where we can have fairly large number of users.

Comment 3 by xingliu@chromium.org, Jan 16 2018

Status: Fixed (was: Assigned)
The config for experiment on M65 is merged.
►

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