1007959 - Reduce HTTP Idle connection timeout on FxOS and Android for conservative battery use

Status: RESOLVED FIXED

(Core :: Networking, defect)

Description

[Steve Workman [:sworkman] (INACTIVE)]

It was recently noticed that HTTP Idle connections on FxOS and Android time out at 10 minutes, versus 115 seconds on desktop (Bug 444328 comment #53). We would like to change this to bring our mobile platforms inline with desktop. There are two main reasons:

1. In the same comment referenced above, Pat notes that he has "old desktop data that shows diminishing returns on the idle persistent connections over 2 minutes". While this data is desktop-centric, it still suggests to us that there isn't a lot of value in having a 10 minute timeout on mobile to keep idle connections alive for reuse, versus 115s.

2. TCP Keepalive pings were enabled in Bug 444328 in order to improve connection reliability. Given that pings are sent every 10s on HTTP Idle connections, the radio may be up and active for a longer period in scenarios involving Idle connections. This, of course, raises a concern about battery use. Note: We're not aware of any hard data that shows that TCP keepalives have had an adverse effect of battery usage. Nonetheless, the potential is there, especially with 10 min timeouts.

Without other data at present, we think reducing the timeout to 115s (or thereabouts) is the right preemptive step to take for now. It would seem that this might strike a balance between reusing idle connections, connection reliability and battery usage.

Comment 1

[Steve Workman [:sworkman] (INACTIVE)]

Attachment: v1.0 Reduce HTTP Idle connection timeout on FxOS and Android for conservative battery use

Pat, as you suggested via email, I have set this to avoid a keepalive cycle. Rather than 110s though, I set it to 109s to avoid an 11th keepalive ping (of course, that's in cases where the keepalive timer isn't reset because of a failed ping or two.

I can set it to 110s if 109 looks too ugly ;)

Comment 2

[Steve Workman [:sworkman] (INACTIVE)]

Thanks Pat!

Pushed to try on Friday, just to be safe - looks good:
https://tbpl.mozilla.org/?tree=Try&rev=730af4ddfabe

Pushed to inbound just now:
https://hg.mozilla.org/integration/mozilla-inbound/rev/7863e387bf4f

Comment 3

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/7863e387bf4f