W3C

Web Performance

29 Apr 2015

Agenda

Attendees

Present
Yoav, Ilya, Plh, Todd, Michael
Regrets
Chair
plh
Scribe
plh

Contents


new draft for Performance Observer

Ilya: how do we want to proceed to land it in performance timeline description?
... I'd like to be more thorough on how events are recorded

https://github.com/w3c/performance-timeline/pull/10

scribe: when do we emit the records?
... ie, initialize the entries, append it to the buffer, ..., and then deliver it to the observer once it's finalized

plh: that means the NT record would be submitted after the loadevent is completed

Todd: agree that entries should only appear once they're completed
... RT and NT entries appear before their entries are filled. was it intentional or not?

Ilya: by product of implementation
... suspect we can't change it

Yoav: also use cases to estimate network performance
... earlier is better

Ilya: we shouldn't make promises that these entries are synchronous. we want to move the devs away that should rely on delivrance of the entries
... no guarantee it will be after the delivery of the resource

Yoav: use case is network estimation
... hard time to expose network information to developers
... having that info early on will allow to do bandwidth estimates
... and use different loading logic based on result
... not sure if it's the best tool to do that
... if it relies on implementation details, I agree we shouldn't expose it

Ilya: next step? merge the PR and iterate?

Todd: agreed

Ilya: I'll merge the PR and start a new one then

Plh: can we publish and get more eye balls?

Resolved: ok to publish a FPWD for Performance Timeline 2

clarifying behavior around failed fetches in Resource Timing

https://github.com/w3c/resource-timing/pull/19

Ilya: current spec doesn't say anything on failed fetches
... we should surface them
... if http server broke, dns would be there but remaining empty

todd: Edge surfaces most of them, just a couple of exception

Plh: ok to merge?

Todd: yes

Yoav: what about redirect?

Ilya: I'll open an issue on resource timing then

https://github.com/w3c/navigation-timing/issues/11

Todd: I'll take that one

Ilya: can we have guidelines for editing the html in webperf?

Plh&Todd: sure

Refactoring Preload and Resource Hints to remove "loadpolicy"

Ilya: resource hints: removed loadpolicy and have prefetch/prerender
... we're now adding optional attributes
... the probability attribute

https://github.com/w3c/resource-hints/pull/27

Ilya: can we merge this one?

All: ok

https://github.com/w3c/preload/pull/17

Ilya: one issue with fetch at the moment. the as attribute will be passed to fetch

Yoav: not sure why why the response has to be tainted in the context
... what's blocking this from having as set a context that is different from the fetch context?

Ilya: if there is a CSP policy with "only img from host", you shouldn't be able to circumvent the policy
... we're stuck on the appropriate header and other settings
... for preload, we could block on that
... or put some clause in the spec and merge

Yoav: we don't have to block in terms of implemetations
... for preload, as can do whatever we think it's right
... I don't think the circumvention applies to preload

Ilya: preload just do a cache thing and then it gets enforced when used by other elements

Yoav: ok we can put a place holder in the spec

Ilya: I'll clarify that
... and then merge 17

Resolved: FPWD for preload

"grouping" of performance entries

https://github.com/w3c/performance-timeline/pull/9

Ilya: thinking we can ignore that one. original proposal was to have a common id
... but folks would like to see a more general purpose mechanism
... ie group by properties
... e.g. getEntries(site, value)

Todd: make sense, looking at the use cases

Ilya: for frame timing, we have a source frame number
... for things like redirect, we'll have to create a fetch id

Plh: did you talk to Anne about the idea of fetch id?

Ilya: nope
... that's pseudo-code
... same return value as getEntriesByType

plh: how about getEntries({type: entryType})
... getEntries({type: entryType, name: entryName})

Todd getEntries({type: 'resource'}) to get resource timings

plh: what about getEntries({foo: "bar", type:"resource"}) ?

Ilya: would return empty list
... I'll close PR9 and open a new one

Issues

http://www.w3.org/2010/webperf/board/

plh: we're not making progress on our backlog of issues. let's elect issues in upcoming calls so we can move forward.

Frame Timing

Ilya: talked to Hixie about adding some mechanism and he is ok if we can get a +1

<igrigorik> https://lists.w3.org/Archives/Public/public-web-perf/2015Apr/0005.html

Todd: I'll go talk to Travis and see if we can +1 this

Next meeting

Plh: next one in two weeks

Summary of Action Items

[End of minutes]

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$Date: 2015/04/29 20:07:12 $