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RE: HTTP 2.0 and a Faster, more Mobile-friendly web

From: Henrik Frystyk Nielsen <henrikn@microsoft.com>
Date: Mon, 30 Jul 2012 06:32:07 +0000
To: Martin Nilsson <nilsson@opera.com>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
CC: Jitu Padhye <padhye@microsoft.com>
Message-ID: <299d3e3339e34be8b233df2a4b5d698b@CH1PR03MB622.namprd03.prod.outlook.com>
Martin,

What scenarios do you have in mind where pipelining does not work? Obviously it only works for GET so for web sites using lots of non-GET requests it won't work but GET is the predominant method on most sites.

We took some pretty normal sites so I do think they represent reasonable data. We'd be happy to expand the sites but the whole point was to show differences in relatively common sites. It is correct that we didn't use cookies. Cookie and UA-header sizes can indeed vary a lot but that is a much more isolated problem to solve that can be done in any number of ways.

As for video (assuming you use TCP) the bottleneck is likely going to be set by TCP throughput. The overhead of HTTP headers will be negligible due to the size of the payload. We'd be happy to do some tests but all things being equal I can say based on experience that adding a credit-based session layer such as SPDY will not perform as well as running straight over TCP for large payloads. The reason is that the credit scheme by its very purpose acts as a throttle so that one session doesn't take the entire bandwidth.

As for minification, the intention is not to do those unbeknownst to the website designer -- it is something that is an integral part of the design of a web site so there is no reason why this isn't a valid optimization.

Thanks,

Henrik

-----Original Message-----
From: Martin Nilsson [mailto:nilsson@opera.com] 
Sent: Sunday, July 29, 2012 3:17 PM
To: ietf-http-wg@w3.org
Subject: Re: HTTP 2.0 and a Faster, more Mobile-friendly web

On Sun, 29 Jul 2012 22:14:02 +0200, Henrik Frystyk Nielsen <henrikn@microsoft.com> wrote:

>
> To compare the performance of SPDY with HTTP/1.1 we have run tests  
> comparing download times of several public web sites using a controlled  
> tested study. The test uses publically available software run with  
> mostly default configurations while applying all the currently available  
> optimizations to HTTP/1.1. You can find a preliminary report on the test  
> results here: http://research.microsoft.com/apps/pubs/?id=170059.

This is an interesting demonstration of a use case HTTP was made for, and  
where HTTP works well. The issues we are facing are non-working pipelining  
in HTTP/1, increase in HTTP header size from things like cookies and  
ua-prof-diff, and streaming of video. It doesn't appear that you are  
testing these issues, so it makes sense that the performance difference  
isn't that great. It would be preferable if HTTP/2 would always win over  
HTTP/1 though.

Since your minify-tests performs non-reversible content modifications, I  
would be very careful to use those results.

/Martin Nilsson

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Received on Monday, 30 July 2012 06:32:52 GMT

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