Date: Wed, 10 Jul 1996 14:45:38 -0700 (PDT)
From: Alexei Kosut <akosut@organic.com>
To: new-httpd@hyperreal.com
Subject: Re: performance ``bugs'' in apache-1.1b4's P-HTTP
In-Reply-To: <199607102050.NAA00578@dash.isi.edu>
Message-ID: <Pine.SOL.3.93.960710144003.27865A-100000@acidik.organic.com>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: owner-new-httpd@apache.org
Precedence: bulk
Reply-To: new-httpd@hyperreal.com

On Wed, 10 Jul 1996, John Heidemann wrote:

> I've found a couple of interactions between Apache-1.1b4's P-HTTP and
> SunOS TCP that significantly reduce performance.  A web page
> summarizing the problems and containing patches resolving them is now
> available at
> <http://www.isi.edu/lsam/publications/phttp_tcp_interactions/>.  (The
> abstract of the web page is attached below.
> 
> I encourage the Apache core team to look at these problems and
> proposed solutions.  If you agree with the analysis,
> then the patches (or their equivalents) should be added to a future
> Apache release.

Wow... this looks useful. We'll certainly look into this.

One note, though: The first problem you note, which has to do with Apache
sending its headers as a seperate segment, cannot unfortunately just be
removed. Unfortunately, Netscape Navigator has a rather serious bug in its
Keep-Alive implementation - if the end of the file is in the same read as
the headers, it will not recognize properly that it is dealing with a
persistent connection, and the connection will hang, waiting for a close.
So we added the fflush() to the code to make sure that it reads the body
seperate from the headers.

Obviously, we'd perfer not to do this, but Netscape makes up 60%-80% of
the market (depending on who you ask), so it really wasn't feasible. One
option is, I suppose, to only do the fflush() for files less than whatever
Netscape's read buffer size is (I tested for this a couple month ago when
I first wrote the keep-alive code, but I now forget - it was 256 or
1024 bytes, or something of the sort).

Thanks.

-- Alexei Kosut <akosut@organic.com>            The Apache HTTP Server 
   http://www.nueva.pvt.k12.ca.us/~akosut/      http://www.apache.org/