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Issue metadata

Status: WontFix
Owner: ----
Closed: Nov 15
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Windows
Pri: 2
Type: Bug



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Chrome Extensions API Message Passing Time Lag on First Response to Message from Content Script

Reported by thomasga...@gmail.com, Oct 26

Issue description

UserAgent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36

Steps to reproduce the problem:
1. Set up a basic extension with background page and content script.
2. Have the content script be loaded at document_start and get the content script to send a basic 'hello world' text message to the background page and wait for a response.
3. Add performance timing measurements to see how long it takes for the first content script message to receive a 'hello back' text response from the background page.

What is the expected behavior?
I would expect the messaging functions to be consistent, whether it is the first message sent or one of many. I understand that the extensions API needs time to establish a connection to the content script but the performance is bad. Performance of subsequent messages after the first is good, about 30-40 ms to get a basic response, no matter what the other workload of the background page might be.

What went wrong?
On average. the first message sent by the content script takes 150-200 ms to receive a response. This kind of lag makes it very difficult to manage operations that require co-ordination between the content script and the background page when interacting with a fast moving web page. Later messages are, without exception, fast (30-40 ms).  

Did this work before? N/A 

Does this work in other browsers? N/A

Chrome version: 69.0.3497.100  Channel: n/a
OS Version: 6.1 (Windows 7, Windows Server 2008 R2)
Flash Version:
 
By the way, this lag is present on synchronous and asynchronous responses.
Without an actual extension and detailed steps-to-reproduce the obvious guesses would be:
* you're using an event page (a non-persistent background page) which takes at least 100ms to wake up.
* the web page process is busy doing something - for example if the content script loads at document_start, the page is being loaded and constructed so the content script can't receive a message during that time.

Also, 30-40ms seems too long for the subsequent comm cycles - should be just a few ms for small message payloads.
Hi thanks for getting back.

I'm not using a non-persistent background page.

That's a good guess about the content script being unable to process the response because the web page process has got so much going on. I was getting those timings from a React JS page which is obviously working hard to construct the HTML. I've check on other pages and the response time drops to a much more manageable 40ms.

Thanks for the typical comms cycle info.
Labels: Needs-Triage-M69
Cc: swarnasree.mukkala@chromium.org
Labels: Triaged-ET Needs-Feedback
Thanks for filing the issue.

@reporter: Could you please provide a sample file of extension or URL that reproduces the issue so that it would be really helpful for triaging the issue.

I think you should close this bug report. The helpful comments from  woxxom@gmail.com helped me get to the bottom of what was going on. Thanks.
Project Member

Comment 7 by sheriffbot@chromium.org, Oct 30

Labels: -Needs-Feedback
Thank you for providing more feedback. Adding the requester to the cc list.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Cc: viswa.karala@chromium.org
Status: WontFix (was: Unconfirmed)
As per comment# 6 from the reporter, closing this issue and marking it as Won't fix.

Thanks!

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