1495537 - Drop TRR timeout from 3 seconds to something close to 1 sec

Status: RESOLVED FIXED

(Core :: Networking: DNS, enhancement, P1)

Description

[Jason Duell]

Right now we wait for 3 seconds for TRR before marking requests failed and falling back to regular DNS.  

Proper fix is bug 1495523 but meanwhile we should drop the timeout to something that gets hit <1% of the time, but is still shorter than 3 Sec.  98% of Cloudflare TRR requests take <1sec, so Daniel and I are thinking dropping the timeout to 1.5 seconds would make sense here. 

Should be a one-liner--let's land and uplift to beta if possible.

Comment 1

[Daniel Stenberg [:bagder]]

Attachment: bug 1495537 - lower the default trr request-timeout to 1500 ms

99.15% of all TRR requests are done within 1.56 seconds (in beta 63) and
1500 milliseconds is already a very long time to wait for a resolve to
fail... The median is 44 ms and 95th percentile is at 471 ms.

MozReview-Commit-ID: CICBAA0cEBd

Comment 2

[Dragana Damjanovic [:dragana]]

Comment on attachment 9013427 [details]
bug 1495537 - lower the default trr request-timeout to 1500 ms

Dragana Damjanovic [:dragana] has approved the revision.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/26d8702b46cd
lower the default trr request-timeout to 1500 ms r=dragana

Comment 4

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/26d8702b46cd

Comment 5

[Daniel Stenberg [:bagder]]

Comment on attachment 9013427 [details]
bug 1495537 - lower the default trr request-timeout to 1500 ms

[Beta/Release Uplift Approval Request]

Feature/Bug causing the regression: Bug 1495537

User impact if declined: For TRR-users with crappy connections or bad DoH server, a less nimble browser.

Is this code covered by automated tests?: No

Has the fix been verified in Nightly?: Yes

Needs manual test from QE?: No

If yes, steps to reproduce: 

List of other uplifts needed: None

Risk to taking this patch: Low

Why is the change risky/not risky? (and alternatives if risky): It's just a pref change

String changes made/needed: none

Comment 6

[Pascal Chevrel:pascalc (PTO until April 26)]

Comment on attachment 9013427 [details]
bug 1495537 - lower the default trr request-timeout to 1500 ms

Pref change to fix a bug in a 63 feature, uplift approved for 63 beta 12, thanks.

Comment 7

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/releases/mozilla-beta/rev/aa5533acaf04