isherman: For debugging the over triggering part, when you feel it is over triggering, can you send a feedback report by going to "Help" and "Report an issue". That report will attach the system logs and histogram metrics which would be useful for debugging. I would obviously need the URL to the feedback report. Thanks.

For more context, we are currently triggering intervention when we think that connection is slower than 3G which maps to an RTT of >= ~275 msec. 

I just filed feedback after hitting this again during local development.  How do I get a URL to the report?  I landed at https://support.google.com/chrome/answer/186850?visit_id=1-636409725634835979-1429306010&p=feedback_confirmation&rd=1 -- is the visit_id sufficient to find the feedback report?

Removed RVG label after removing some of the comments.  Issue 765378  tracks the overtriggering bug.

Thank you for investigation.

So, unexpected intervention triggering are discussed at  Issue 765378 , but I have another question about the ~1000 lines warnings. Do you really have ~1000 WebFonts entries in the page?

I'm wondering if I could omit the repeated warnings on the same WebFont URL. But if URL are different, I think it's still useful for developers who open the console.

A recent case that I saw has 585 lines, attached.  I believe that I saw closer to ~1000 in a previous case; but regardless, it's quite a lot ;-)

Deleted: console_spam.txt 97.9 KB

console_spam.txt 97.9 KB View Download

Looks like we're reporting this for every @font-face rule, regardless of whether it's used or not.
Maybe we should report it when the font started to load, in RemoteFontFaceSource::BeginLoadIfNeeded().

Thanks!

I will adopt what ksakamoto suggests. That would help to minimize the number of warnings.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/667294139c3c90290ad5297f5bb90cfa82f0d2cd

commit 667294139c3c90290ad5297f5bb90cfa82f0d2cd
Author: Takashi Toyoshima <toyoshim@chromium.org>
Date: Wed Sep 20 00:31:19 2017

WebFonts intervention: show a warning on actually making a request

Before this change, warnings are shown for all font-face rules.
This will spam the console if specified css files contain many
unused rules.

With this change, warnings are shown on making actual font loading
requests, or when fonts are requested to use in the page rendering.

Bug:  764204 
Change-Id: I6b3e6627a5c6d5b92e36408ef5ff0951e7903bc7
Reviewed-on: https://chromium-review.googlesource.com/672178
Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Reviewed-by: Kinuko Yasuda (slow) <kinuko@chromium.org>
Commit-Queue: Takashi Toyoshima <toyoshim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503006}
[modify] https://crrev.com/667294139c3c90290ad5297f5bb90cfa82f0d2cd/third_party/WebKit/Source/core/css/RemoteFontFaceSource.cpp

One possible fix was landed.
Warnings should be shown only for actually used WebFonts. I hope this can improve users' experience.

Ilya, could you check if this change helps your case?

Intervention false trigger would not happen on POSIX ports as far as I heard from tbansal. So you can check it on HEAD/Canary for Mac or Windows, I think.

If it does not work, please reopen this bug again.

Thanks!  I'll test this once the Canary version updates to include the fix.

I can confirm that the mitigation is working well.  I now only see a single line logged to the console, which is much more manageable.