1512210 - Consider reporting network timing information even before the request completes

Status: NEW

(Core :: Gecko Profiler, defect, P3)

Description

[Markus Stange [:mstange]]

Consider these two profiles:
 1. Captured in the middle of loading: https://perfht.ml/2SAVR5x
 2. Captured after the end of loading: https://perfht.ml/2SAVCHF

For many of the loads, data had already started arriving from the server at the time the first profile was captured. But the profile does not contain any information about this. It would be nice to find a way to put this information into the profile.

Comment 1

[Julien Wajsberg [:julienw]]

Probably we'll want to send one marker between each phase (when one phase starts and another ends). Or maybe that's not run in sequence and then we might want to have one marker start and one marker end for each phase.

Comment 2

[Honza Bambas (:mayhemer)]

We have the initial timing information from the nsHttpTransaction in nsHttpChannel::OnStartRequest (or its equivalent "http-on-examine-response", or "..-examine-merged-response" for validated responses, or "-examine-cached-response" for cache reads). I don't think it makes sense to do this earlier because DNS/TCP/TLS are racing and there is no good point prior this one to look for that information.

Does that answer the questions here?

Comment 3

[Julien Wajsberg [:julienw]]

Thanks for the pointers.
We won't have time to look at this very soon anyway, but now we have some information for when we'll want to revisit the network marker implementation.