How many speculative connections is enough (or too many?)

[Jason Duell]

So right now we'll launch a new speculative TCP connection (up to 6) for
each call to the speculative connect API:

https://bugzilla.mozilla.org/show_bug.cgi?id=1383299#c14

(For HTTP/2, presumably they get merged into one socket once we figure out
we're doing H/2, but we won't know that till we actually issue an HTTP
request IIUC).

1) Are we happy with this as the default behavior? I'm not sure we want
to open this many speculative sockets to the same host.

2) In this bug we're talking about possibly calling the speculative API
multiple times for the same logical channel (once when the user gets close
to a link with the mouse, once when they click down on it, etc, and
possibly also in some central location(s) in the parent before we send off
a URIload notice to the child):

https://bugzilla.mozilla.org/show_bug.cgi?id=1383299#c14

I'm thinking we should add a "no-dupe" version of speculative connect for
this behavior (i.e. it wouldn't start a new speculative connection if
there's one to that origin already). Any other ideas?

3) For the case where they want to call the speculative API in the parent
when we actually know 100% that we'll be navigating there (i.e the only
reason for the call is to launch the socket immediately without having to
wait for the parent to notify the child about the load), would we want to
do the same thing we do for regular channels (open 2 sockets in staggered
succession)?

Jason

[Patrick McManus]

in general connection costs are low in bandwidth and low in cpu but high in
latency.. so neither end really minds if we make too many. perhaps the
constant 6 is wrong, but I think any adjustment should be based on data
unless there is a firm problem beig reacted to.

determining h2 does not require http, but it does require tls to be
complete.. this info is cached.

> --
> You received this message because you are subscribed to the Google Groups
> "Necko" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to necko+un...@mozilla.com.
> To post to this group, send email to ne...@mozilla.com.
> To view this discussion on the web visit https://groups.google.com/a/
> mozilla.com/d/msgid/necko/CAL0FBF-9Ueg8kFXJaaYDAHAxDWxZ3fTj4-
> GmwafShEBYKaHVug%40mail.gmail.com
> <https://groups.google.com/a/mozilla.com/d/msgid/necko/CAL0FBF-9Ueg8kFXJaaYDAHAxDWxZ3fTj4-GmwafShEBYKaHVug%40mail.gmail.com?utm_medium=email&utm_source=footer>
> .
>