- From: Willy Tarreau <w@1wt.eu>
- Date: Tue, 21 Oct 2014 11:40:33 +0200
- To: Roberto Peon <grmocg@gmail.com>
- Cc: Mark Nottingham <mnot@mnot.net>, RUELLAN Herve <Herve.Ruellan@crf.canon.fr>, Amos Jeffries <squid3@treenet.co.nz>, Greg Wilkins <gregw@intalio.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
On Tue, Oct 21, 2014 at 11:25:05AM +0200, Willy Tarreau wrote: > Hi Roberto, > > On Tue, Oct 21, 2014 at 12:01:19AM -0700, Roberto Peon wrote: > > While I prefer the indexing scheme of the previous draft, this proposal > > would be better than what is currently drafted. > > Thanks. Do you know how the following representations are ordered in > terms of frequency/probability ? > > - Indexed Header Field Representation > - Literal Header Field with Incremental Indexing > - Literal Header Field without Indexing > - Literal Header Field never Indexed > > I would guess they should appear in the order above, though that's not > obvious to me. And I'm still sad at the idea of leaving many encoding > values unused (eg: static header values above 16). Thus, we'll typically > have 48 possible values out of 256 for the first byte that will never be > emitted just for the indexed headers alone, that's a 20% waste, and I > really think we can do better without making anything more complex. I > just need to ensure I don't propose something stupid. For example something like this (CCing Greg who also has concerns about all this), which supports a single-byte encoding for : - 14 or the 16 static headers with values - all 62 static headers for literals - 62 dynamic headers for literals +---+---+----------------------+ | 1 | D | index 6+ | literal with incremetal indexing +---+---+----------------------+ +---+---+----------------------+ | 0 | 1 | index 6+ | indexed dynamic header +---+---+----------------------+ +---+---+---+---+--------------+ | 0 | 0 | 1 | 1 | index 4+ | indexed static header +---+---+---+---+--------------+ +---+---+---+---+--------------+ | 0 | 0 | 1 | 0 | size 4+ | max dynamic table size change +---+---+---+---+--------------+ +---+---+---+---+---+----------+ | 0 | 0 | 0 | 0 | D | index 3+ | literal without indexing +---+---+---+---+---+----------+ +---+---+---+---+---+----------+ | 0 | 0 | 0 | 1 | D | index 3+ | literal never indexed +---+---+---+---+---+----------+ Willy
Received on Tuesday, 21 October 2014 09:42:13 UTC