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From Cliff Skolnick <cl...@organic.com>
Subject Re: performance ``bugs'' in apache-1.1b4's P-HTTP
Date Thu, 11 Jul 1996 02:44:47 GMT
On Wed, 10 Jul 1996, Chuck Murcko wrote:

> Robert S. Thau liltingly intones:
> > 
> >   Wow... this looks useful. We'll certainly look into this.
> > 
> > One thing which it would be helpful to know is how much the second
> > tweak to the server (disabling the Nagle algorithm) helps on its own
> > (and whether it does anything at all, perhaps by allowing the window
> > to open up a bit wider, to cure the effects of problem one, the MIME
> > header partial packet --- probably not, I know, but perhaps it's worth
> > asking).
> > 

Using writev() instead of a whole series of write() calls is a big
perfomance win.  Sun's internet engineering guys have been trying to
convince me this is a really good thing.  They have the data to back it
up, but this is not a small effort.

Turning off the nagle algorithm is nto a good idea.  We ran with this off
at Organic for a while and we ended up increasing our packet count
measurably and burning lots more of our lines because of this.  From my
experience this is not a good thing, and the TCP/IP gurus who say use
writev() very strongly also say very strongly not to do this.

BTW anyone running solaris 2.5 will notice a real nasty TCP/IP bug that
causes lots of retransmittions.  Sun is almost ready with the latest patch
for this.  I'll post details when I get my hands on this :)

Cliff

--
Cliff Skolnick, CIO      http://www.organic.com/     cliff@organic.com
Organic Online, Inc.       ** we're hiring **           (415) 278-5650
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety." -- Benjamin Franklin, 1759


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