Date: Sat, 1 Mar 1997 19:49:54 -0500 From: "David S. Miller" <davem@jenolan.rutgers.edu> To: bakul@chai.plexuscom.com Cc: dennis@etinc.com, dg@root.com, proff@iq.org, hackers@FreeBSD.ORG Subject: Re: optimised ip_input Message-ID: <199703020049.TAA09426@jenolan.caipgeneral> In-Reply-To: <199703012242.RAA04265@chai.plexuscom.com> (message from Bakul Shah on Sat, 01 Mar 1997 17:42:33 -0500)
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Date: Sat, 01 Mar 1997 17:42:33 -0500
From: Bakul Shah <bakul@chai.plexuscom.com>
2) Profiling the networking code in a production environment ought
to point out the `hot spots' where much of the time is spent
under various conditions. Measure various costs by changing data
structure sizes and feeding similar traffic. Find out *why* the
hot spots are the way they are; gain a deeper understanding of
the structure and behavior of the networking code.
Just a heads up, and this is from my own experience profiling this
stuff. For freely running connections (ie. application at receiving
end or sending end is continually filling a healthy pipe which is
being kept reasonably full) the kernel spends a significant portion of
time in soreceive() and sosend(). Unfortunatly, last time I checked,
those are not fun functions to hack on and optimize due to their
complexity.
---------------------------------------------////
Yow! 11.26 MB/s remote host TCP bandwidth & ////
199 usec remote TCP latency over 100Mb/s ////
ethernet. Beat that! ////
-----------------------------------------////__________ o
David S. Miller, davem@caip.rutgers.edu /_____________/ / // /_/ ><
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