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    SubjectRe: 2.2.18Pre Lan Performance Rocks!
    On Tue, Oct 31, 2000 at 02:52:11PM -0700, Jeff V. Merkey wrote:

    > Ingo Molnar wrote:
    > >
    > > On Tue, 31 Oct 2000, Pavel Machek wrote:
    > >
    > > > > Excuse me, 857,000,000 instructions executed and 460,000,000
    > > > > context switches a second -- on a PII system at 350 Mhz. [...]
    > >
    > > > That's more than one context switch per clock. I do not think so.
    > > > Really go and check those numbers.
    > >
    > > yep, you cannot have 460 million context switches on that system,
    > > unless you have some Clintonesque definition for 'context switch' ;-)

    > The numbers don't lie. You know where the code is. You notice that
    > there is a version of
    > the kernel hand coded in assembly language. You'l also noticed that
    > it's SMP and takes ZERO LOCKS during context switching, in fact, most of
    > the design is completely lockless.

    Ah ha ha ha!!!! Sure they do! You're just quoting statistics
    measured under whatever conditions you imposed.

    Numbers lying? I think the famous line has been variously
    attributed to either Mark Twain or Disraeli (don't know which really
    coined the phrase) but it's been said that there are three kinds of
    lies "Lies, Damn Lies, and Statistics". Yes numbers do lie. Sometimes
    it's the GIGO law and sometimes its just the fact that if you abuse
    statistics long enough they will tell you ANYTHING. Sometimes it merely
    the person manipulating^H^H^H^H^H^H^H^H^H^H^H^Hproviding the numbers.

    BTW... I was going to stay OUT of this rat trap, but since I'm
    in for a dime, I might as well be in for a dolar...

    <Minor Rant>

    Comparisons have been made between the performance of Linux with
    early (3.x, 4.x) versions of Novell. ANYONE who wants to compare Linux
    with that bug ridden, unreliable swamp of headaches and security holes
    (somewhere in my archives I have the virus launcher that BYPASSES the
    3.x login program) should be beaten about the head with a good textbook
    on reliable coding techniques. Novell made its hayday by beating the
    bejesus out of TCP/IP and others primarily by disabling checksumming,
    memory protection, and other reliability techniques. Yes, they got
    better performance on low performace processors, but at what cost? Now
    we cover their performance with reliability and superior hardware. I
    remember one misguided soul wanting to run IPX over SLIP pleading for help
    on the Novell mailing list years ago. Let's see... SLIP eliminates the
    MAC layer checksumming and IPX eliminates the error checking on the next
    layer up... Yup... There was a receipe for random acts of terrorism.
    Now we have PPP (this was in the days BEFORE PPP) and you could do it.
    IPX depended on the lower layers for data integrity and and SLIP depended
    on the layer above it. Ooooppppssss....

    Then we had the Novel 5.x NFS server that allow you to create
    scripts that were SUID to root just by making them read only to the
    Novell workstations (ok - that's not performace related - I just think
    that security should be given a LITTLE thought). I worked at an outfit
    (Syntrex) that saw themselves as becoming the "K-Mart of Novell" and I
    was told that Novell was the be all and end all of networking and there
    was really no future in this antiquated TCP/IP stuff. I was laid off and
    given all sorts of nice neat little toys like an AT&T source license
    because they saw no future in Unix or TCP/IP. (Bitter - no... I have
    had my revenge in spades... They had no clue what they gave away and
    let slip through their fingers! :-) )

    Now, Novell has been dragged kicking and screaming into the TCP/IP
    world, and Novell has been forced to add memory protection (at a performace
    cost) to their servers, and the outfit that thought TCP/IP was history
    is now history (Syntrex went Chapter 13 about 10 years ago), and I've had
    the pleasure of slamming one particularly simple minded Novell rep (another
    ex Syntrex inDUHvidual) with more than one security hole (the perl module
    on the Novell web server was an absolute classic).

    My point here is that packets per second don't mean jack shit if
    you can't do it reliably and you can't do it securely. Novell failed on
    both of those counts and those are a contributing factor in their current
    troubles. They built their reputation on performance that was achieved at
    the expense of reliability and security. Now they have to play with the
    big boys and all the nasty kiddies out there who don't play nice.

    Performance is important. Performance is desirable. Efforts to
    improve performance are worthwhile. But performance should NEVER come at
    the cost of security or reliability or integrity. Comparisions with high
    performance systems which lacked security, reliability, and data integrity
    are suspect AT BEST. We should NEVER give up the quest for better
    performance but comparisons to an inferior operating system which can pump
    out packets faster than us is not the threat some people would like it to be.

    </Minor Rant>

    My regards and respects to Jeff. He says he was responsible for the
    Novell 4.x and 5.x systems. I note that he omitted the 3.x OS. Acknowledged
    and respected! In my earlier days, I was the kernel jock responsible for a
    proprietary version of XENIX and worked on Microport UNIX (may someone
    forever drive a stake through that bastard's heart) and SCO Unix. I'm
    "contaminated goods" for certain projects so I can't contribute to certain
    applications like Taylor UUCP because I have legal source code to HDB UUCP
    (as if UUCP means jack in today world). Does the current taylor UUCP have
    the most possible efficient checksumming algorithm for the UUCP 'g' protocol?
    No... No way... I've seen one that stomps Taylor UUCP's ass and takes names
    from the AT&T SVR5 release 3.2 source tapes (took me a week to figure out just
    how it worked - damn those comment strippers). Does it matter? Not one bit.

    I want to see Linux excel. Does that mean that it has to beat
    every benchmark set by an operating system that cut every corner that
    would cause Linus to turn into a Quake Balrog? I think not.

    > Jeff

    > > Ingo

    Mike
    --
    Michael H. Warfield | (770) 985-6132 | mhw@WittsEnd.com
    (The Mad Wizard) | (678) 463-0932 | http://www.wittsend.com/mhw/
    NIC whois: MHW9 | An optimist believes we live in the best of all
    PGP Key: 0xDF1DD471 | possible worlds. A pessimist is sure of it!

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