Re: [tcpm] TCP Tuning for HTTP - update

Willy Tarreau <> Wed, 17 August 2016 06:51 UTC

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Date: Wed, 17 Aug 2016 08:45:45 +0200
From: Willy Tarreau <>
To: Joe Touch <>
Cc: Mark Nottingham <>,, HTTP Working Group <>, Patrick McManus <>, Daniel Stenberg <>
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Subject: Re: [tcpm] TCP Tuning for HTTP - update
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Hi Joe,

On Tue, Aug 16, 2016 at 10:23:01PM -0700, Joe Touch wrote:
> > Other people in the HTTP *and* TCP communities have commented that such a
> > document would be very useful, whether or not it's something "new that
> > wasn't known 20 years ago". 
> We don't need to issue new documents for people who don't read old ones.

I've just checked the two documents you referenced. They seem to be very
well detailed but they are *scientific* research. What Daniel created are
configuration advises for people who need to configure their servers. Yes
as you mentionned they look like man pages precisely because the purpose
is to ensure they're easily understood by people who are just seeking some
help to improve their configuration. You cannot expect a server admin to
read scientific papers explaining some TCP models with some formulas to
know what to do on their servers.

Also, I don't know if there have been any update, but these documents use
SunOS 4.1.3 running on a sparc 20 as a reference. While I used to love
working on such systems 20 years ago, they predate the web era and systems
have evolved a lot since to deal with high traffic. I remember by then I
used to be impressed when seeing a server sustain 50 connections per second.
Now when someone tells me he's limited to 100000 connections per second on
a single server, I ask how they bound their interrupts to see if there's
some headroom to go further.

So you need to expect that only researchers and maybe TCP stack developers
will find your work useful these days, server admins can hardly use this
anymore. However it is very possible that some TCP stacks have taken benefit
of your work to reach the level of performance they achieve right now, I
don't know. Thus I think that Daniel's work completes quite well what you've
done in that it directly addresses people's concerns without requiring the
scientific background.