1366224 - Turn on RCWN for a few days on Nightly

Status: RESOLVED FIXED

(Core :: Networking, enhancement)

Description

[Valentin Gosu [:valentin] (he/him)]

For the past month I have been running my nightly with RCWN enabled, and the racing thresholds set very low (value of 1).
I think it would be very useful to get some preliminary data back on Nightly. I propose we turn on the pref, maybe also lowering the default thresholds, and see what happens. It would be great to see a spike in telemetry (in the right direction), and hopefully no new crash reports or regressions.

Comment 1

[Honza Bambas (:mayhemer)]

+1

Comment 2

[Valentin Gosu [:valentin] (he/him)]

Attachment: Bug 1366224 - Turn on RCWN (Race cache with network) for a few days on nightly

Review commit: https://reviewboard.mozilla.org/r/141568/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/141568/

Comment 3

[Valentin Gosu [:valentin] (he/him)]

Attachment: Bug 1366224 - Change RCWN thresholds to race more often

The previous limits were chosen a bit arbitrarily, and didn't trigger racing too often. These limits are also quite arbitrary, but should cause us to race more.
These limits can be removed once we implement bug 1325331 and we can make a fair approximation regarding the cache latency.

Review commit: https://reviewboard.mozilla.org/r/141570/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/141570/

Comment 4

[Patrick McManus [:mcmanus]]

Comment on attachment 8870088 [details]
Bug 1366224 - Change RCWN thresholds to race more often

https://reviewboard.mozilla.org/r/141570/#review145680

Comment 5

[Patrick McManus [:mcmanus]]

I think you can just land the reviewed code from comment 4 without worrying about pref-off.

Comment 6

[Patrick McManus [:mcmanus]]

yes, this data we need to meet our 57 goals.

As for turning on the feature, I'm going to suggest a 1 day trial - get it into one nightly and then pref it off before you even know what the data is. you ought to be able to use the buildID to look at the telemetry, even though ime it won't come in for a couple days afterwards.

also make sure you're familiar with the "nightly soft code freeze" memo ritu sent to dev-platform a week ago.

I'll also ni ritu here just for his fyi.

Comment 7

[Patrick McManus [:mcmanus]]

Comment on attachment 8870087 [details]
Bug 1366224 - Turn on RCWN (Race cache with network) for a few days on nightly

https://reviewboard.mozilla.org/r/141568/#review145682

for 1 build, r+

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0452d9bf6369
Turn on RCWN (Race cache with network) for a few days on nightly r=mcmanus
https://hg.mozilla.org/integration/autoland/rev/31c081e5277b
Change RCWN thresholds to race more often r=mcmanus

Comment 9

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

Thanks for the heads-up. Marcia and Philipp who monitor Nightly crash rates are also aware of this now.

Comment 10

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/0452d9bf6369
https://hg.mozilla.org/mozilla-central/rev/31c081e5277b

Comment 11

[Marcia Knous [:marcia]]

Valentin: We are seeing a pretty big crash spike - Bug 1367742#c2 which is now the #2 top crash suggests it might be attributed to this being turned on. How long will we leave this turned on?