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Re: Call for Consensus: Remove "reference set" from HPACK (to address #552)

From: Tatsuhiro Tsujikawa <tatsuhiro.t@gmail.com>
Date: Wed, 16 Jul 2014 22:30:38 +0900
Message-ID: <CAPyZ6=KFvJTb5-mLKJmfWvGOeoQSHQ9jTJAM2YvfzXbSUSoA6A@mail.gmail.com>
To: Greg Wilkins <gregw@intalio.com>
Cc: HTTP Working Group <ietf-http-wg@w3.org>
On Wed, Jul 16, 2014 at 11:13 AM, Greg Wilkins <gregw@intalio.com> wrote:

> I ran the hpack test data through the various options being discussed for
> several different header table sizes:
>
> HPACK/HEADER TABLE 010244096 16384h2-12 64.22%47.06%42.18% 41.82%
> h2-12-noRefSet64.22% 47.39%42.57%42.44% h2-12-noRefSet-noCopy64.22%47.16%
> 42.50%42.67%h2-12-noRefSet-noCopy-static1 64.22%47.18%42.36% 40.97%
>
> There is actually very little variation in results +/- 1% which is likely
> to be below the variation due to different data sets.       So on that
> basis we should go for the simplest mechanism, which is either
> h2-12-noRefSet-noCopy  or h2-12-noRefSet-noCopy-static1
>
> But if we trust that data set, then the best compression was achieved with
> h2-12-noRefSet-noCopy-static1 and a large header table.    Also
> h2-12-noRefSet-noCopy-static1 was better than h2-12-noRefSet-noCopy for all
> but the 1024 table size.
>
> So on this data we should go with h2-12-noRefSet-noCopy-static1
>
> h2-12 == the HPACK used by draft 12 of HTTP
> noRefSet == no Reference Set
> noCopy == Do not copy static fields to the header table
> static1 == Static indexes are 1-61, dynamic are 62-...
>
>
​Thank you for the experimentation.​

​From the table, h2-12 shows best efficiency to me.
Also the result depends on the encoder algorithm and data set.
If someone does the same tests with their own implementation, the result
may vary.

Best regards,
Tatsuhiro Tsujikawa
​




>
> cheers
>
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> On 16 July 2014 11:01, James M Snell <jasnell@gmail.com> wrote:
>
>> On Tue, Jul 15, 2014 at 1:21 PM, Martin Thomson
>> <martin.thomson@gmail.com> wrote:
>> > On 15 July 2014 12:14, Jason Greene <jason.greene@redhat.com> wrote:
>> >> Whatever happened with this idea? Searching my archives I couldn’t
>> find it getting rejected. I also don’t see an issue filed for it.
>> >
>> > Search for "typed codecs" and variations on the same.
>> >
>> > Also: http://tools.ietf.org/html/draft-snell-httpbis-bohe-13  (note
>> > the version number)
>> >
>>
>> Note also that the version number is reflective only of my own
>> editing/publishing style and not of any particular amount of
>> consideration from the WG
>>
>> - James
>>
>
>
>
> --
> Greg Wilkins <gregw@intalio.com>
> http://eclipse.org/jetty HTTP, SPDY, Websocket server and client that
> scales
> http://www.webtide.com  advice and support for jetty and cometd.
>
Received on Wednesday, 16 July 2014 13:31:25 UTC

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