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Re: HEADERS and flow control

From: Matthew Kerwin <matthew@kerwin.net.au>
Date: Fri, 23 May 2014 10:28:48 +1000
Message-ID: <CACweHNDqWN9Y7BObrN_yGw_AhfXwb4F0pLXKpuddY1mBESORDQ@mail.gmail.com>
To: Greg Wilkins <gregw@intalio.com>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
On 23 May 2014 04:08, Greg Wilkins <gregw@intalio.com> wrote:

>
> I think the hpack tail is really wagging this protocol dog!
>
> Currently hpack is forcing this protocol to have a user accessible non
> flow controlled un-segmentable size unlimited meta data streams that has
> strict ordering criteria resulting in significant parallel slow down.
>
>
​It's also the single most complex part of the spec​ to implement. My
side-project implementation has hiccupped and stalled every time it's
bumped into continuation frames and hpack. I've currently stopped all work
on it until I have time to go through and read in much more detail the
hpack draft, and some related archived conversations on the list, and
Canonical prefix encodings and Huffman coding, etc.

If I could negotiate not using HPACK I could probably have the rest of my
implementation up to some sort of interop testing by now.


​
​

>
> ​
> Our experience with SPDY is that the vast majority of the speed up comes
> from avoiding round trips rather than compression.    This means you need
> good multiplexing and good push mechanisms.  Compression is worthwhile, but
> I suspect that 90% of the gains can be achieved with a far simpler
> algorithm that does not impose such onerous constraints on the framing.​
> ​​
>
>
>


-- 
  Matthew Kerwin
  http://matthew.kerwin.net.au/
Received on Friday, 23 May 2014 00:29:17 UTC

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