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Re: Review: http://www.ietf.org/id/draft-mbelshe-httpbis-spdy-00.txt

From: Patrick McManus <pmcmanus@mozilla.com>
Date: Wed, 29 Feb 2012 13:46:54 -0500
To: Willy Tarreau <w@1wt.eu>
Cc: Amos Jeffries <squid3@treenet.co.nz>, ietf-http-wg@w3.org
Message-ID: <1330541214.2182.305.camel@ds9>
On Wed, 2012-02-29 at 19:03 +0100, Willy Tarreau wrote:

> > To bring this back to compression - I just took a set of 100 compressed
> > real headers, and passed them through a decompress/recompress filter
> > 1000 times in 350 milliseconds on one core of a rather unimpressive i5.
> > Spdy would do it faster because it tends to window things smaller than
> > the default gzip. So that's a cpu overhead of .35ms per set of 100. The
> > headers were reduced from 44KB (for the set of 100) to about ~4KB.
> > That's probably a reduction from 31 packets to 3. IW=4 means that's a
> > difference of 3 rtt's of delay to send 31 packets uncompressed vs 0
> > delay to send 3 compressed. 
> That's precisely what worries me a lot. You were able to compress "only"
> 3000 requests per second on an i5, 

3000 sets of 100 http transactions per second on 1 core of an i5 with a
lame implementation. So that's 300,000 http transactions per second per
core on a chip that costs ~$50 a core. not a big factor.

> which means only 1500 request+response
> per second for a proxy or gateway. 

150,000 per second.

I'll also note that it's not a moral failing if we specify a protocol
that's good for the Internet that can be gatewayed to one that is better
for back offices, although I don't think that has to happen. I think the
work of the Internet protocol is the more important work of the IETF. 
Received on Wednesday, 29 February 2012 18:47:39 UTC

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