Re: Is a faithful HTTP/2 response scheduler necessarily O(n) in the worst case?
Amos Jeffries <squid3@treenet.co.nz> Thu, 26 January 2017 09:54 UTC
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From: Amos Jeffries <squid3@treenet.co.nz>
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Date: Thu, 26 Jan 2017 22:51:18 +1300
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Subject: Re: Is a faithful HTTP/2 response scheduler necessarily O(n) in the worst case?
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On 25/01/2017 12:20 p.m., Patrick McManus wrote: > media frames are another really good use case for linear orders. These, and > Tom's cases, were all cited as use cases during standardization. > Gateways translating for HTTP/1 clients also need their responses to be as linear as possible to match the 1.1 sequence. Otherwise they will be forced to either spend RAM caching response data with a blocked pipeline, or forgoe the h2 multiplexing and PUSH benefits. > I think the discussion about how to process that organization is germane > and interesting (chair hat!), and we should do that cognizant that this is > an expected use of the priority feature. > > On Wed, Jan 25, 2017 at 8:09 AM, Tom Bergan <tombergan@chromium.org> wrote: > >> On Tue, Jan 24, 2017 at 2:55 PM, Kazu Yamamoto <kazu@iij.ad.jp> wrote: >> >>> Hi Tom, >>> >>>>> http://www.mew.org/~kazu/material/2015-http2-priority2.pdf >>>>> http://www.mew.org/~kazu/doc/paper/http2-haskell-2016.pdf >>>> >>>> Thanks. IIUC, the algorithms described in both links are still at least >>>> O(depth), which can be O(n) for dependency trees generated by certain >>>> clients such as Chrome. >>> >>> Yes. Your understanding is correct. >>> >>> If a browser creates a list-like tree, I think it is misuse of priority. >>> And servers should limit the depth of trees. >> >> >> Why is that a misuse of priority? It seems entirely reasonable for a >> client to specify a mostly-linear order. There is a very good reason for >> this: inside HTML pages, CSS links and synchronous scripts must be >> evaluated in the order they appear in the HTML file. This implies that the >> server should send those resources in a linear order. This is exactly the >> rationale behind Chrome using mostly-linear orders. (This is not to say >> that mostly-linear orders are not occasionally problematic -- they are >> <https://bugs.chromium.org/p/chromium/issues/detail?id=651538#c1> -- but >> there are good reasons to linear orders at least some of the time.) >> >> (sorry for the duplicate message, replied from the wrong address) >> >
- Is a faithful HTTP/2 response scheduler necessari… Tom Bergan
- Re: Is a faithful HTTP/2 response scheduler neces… Kazuho Oku
- Re: Is a faithful HTTP/2 response scheduler neces… Kazu Yamamoto ( 山本和彦 )
- Re: Is a faithful HTTP/2 response scheduler neces… Stefan Eissing
- Re: Is a faithful HTTP/2 response scheduler neces… Tom Bergan
- Re: Is a faithful HTTP/2 response scheduler neces… Kazu Yamamoto ( 山本和彦 )
- Re: Is a faithful HTTP/2 response scheduler neces… Tom Bergan
- Re: Is a faithful HTTP/2 response scheduler neces… Patrick McManus
- Re: Is a faithful HTTP/2 response scheduler neces… Kazuho Oku
- Re: Is a faithful HTTP/2 response scheduler neces… Tatsuhiro Tsujikawa
- Re: Is a faithful HTTP/2 response scheduler neces… Kazu Yamamoto ( 山本和彦 )
- Re: Is a faithful HTTP/2 response scheduler neces… Cory Benfield
- Re: Is a faithful HTTP/2 response scheduler neces… Stefan Eissing
- Re: Is a faithful HTTP/2 response scheduler neces… Amos Jeffries