CPU load due to IP networking

From: jbl (levinjb_at_gmail.com)
Date: 06/22/05

  • Next message: hiwa: "A host denying server role" 
    Date: 21 Jun 2005 16:33:07 -0700

    I've been looking for some information on the web, in white papers and
    even on Usenet, but if it exists I can't seem to put together a search
    that finds it. I'm asking here if anyone knows of something along
    these lines and can point me to it.

    I'm looking for some data on the approximate resource cost,
    particularly CPU usage cost, of doing networking in a typical system,
    in particular a Unix-like system (linux is a suitable example) and
    vxworks (hence the crossposting).

    I'm not looking for bandwidth / capacity type data (e.g., N kpkts/sec
    or M MB/sec); these measures are fairly common and there are lots of
    examples on the web. Rather I'm looking for an approximate cycle or
    instruction count list, like this: I'd like to know that the CPU will
    expend A instructions (or cycles) per IP packet in, B cycles per IP
    packet out, C cycles per TCP packet in, D cycles per TCP packet out,
    etc.; and T cycles per connection per second, and U cycles per second
    for background processing, etc. Then using these numbers loosely as
    rules of thumb, and given a traffic model and a CPU of a certain type
    and speed, I could compute a rough estimate of what portion of the CPU
    capacity would be consumed by networking activities. I'd also like to
    include not only TCP/IP but UDP and some other router-like protocols
    (e.g. BGP or OSPF routing) and layer 2 activity (such as implied by
    ethernet connections.

    I hope it's clear enough what kind of data I'm looking for, and that I
    only need rough numbers. If anyone knows of something of this sort
    that's been published, for any operating system, actually, I'd
    appreciate a pointer.

    Thanks / JBL

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