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Re: Stuck in a train -- reading HTTP/2 draft.

From: Matthew Kerwin <matthew@kerwin.net.au>
Date: Thu, 19 Jun 2014 08:03:17 +1000
Message-ID: <CACweHNC3Y85ZSjiP1gXtXZijWakjH3Qvo3euAdk++8467RhnPQ@mail.gmail.com>
To: James M Snell <jasnell@gmail.com>
Cc: Poul-Henning Kamp <phk@phk.freebsd.dk>, Mark Nottingham <mnot@mnot.net>, Jason Greene <jason.greene@redhat.com>, Greg Wilkins <gregw@intalio.com>, HTTP Working Group <ietf-http-wg@w3.org>, Martin Thomson <martin.thomson@gmail.com>
Date is used to calculate Age. I imagine it's actually in use by caches (?)

Coding it into the headers frame makes sense, but is there a rule
about it being set in requests?

On 19/06/2014, James M Snell <jasnell@gmail.com> wrote:
> Yep. Using a variable length encoding 5 bytes is the max we would need for
> all practical purposes.
>
> I'm all for dropping Date entirely, tho. That doesn't help us with the
> other date headers, but it helps. Last-Modified and If-Modified-Since are
> both great candidates for five-byte encoding.
>
> It's too bad the WG didn't pick up on such an obvious improvement but, oh
> well I guess.
>
> - James
> On Jun 18, 2014 1:36 PM, "Poul-Henning Kamp" <phk@phk.freebsd.dk> wrote:
>
>> In message <
>> CABkgnnVT8zGSiU8fDqNtiaL+f2ziBytyP_SUGyPSL2anZf546Q@mail.gmail.com>
>> , Martin Thomson writes:
>> >On 18 June 2014 13:17, Poul-Henning Kamp <phk@phk.freebsd.dk> wrote:
>> >> In that case we should transfer the time as a POSIX time_t in the
>> >> HEADERS frame.  Wasting time huffman encoding dates and still
>> >> using 24 bytes where 8 would be plenty is just plain stupid.
>> >
>> >Yeah, that was discussed and rejected, though not permanently.  I
>> >think that James worked out that 5 bytes was enough in the short term
>> >with a little epoch tweaking.
>> >
>> >And yes, we are plain stupid.  Think of the cost of parsing that stuff
>> >as opposed to doing ntohl().
>>
>> Indeed.  Ascii Timestamps amount for about 30% if Varnish CPU load :-/
>>
>> --
>> Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
>> phk@FreeBSD.ORG         | TCP/IP since RFC 956
>> FreeBSD committer       | BSD since 4.3-tahoe
>> Never attribute to malice what can adequately be explained by
>> incompetence.
>>
>>
>


-- 
  Matthew Kerwin, B.Sc (CompSci) (Hons)
  http://matthew.kerwin.net.au/
Received on Wednesday, 18 June 2014 22:03:45 UTC

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