Re: FreeBSD MySQL still WAY slower than Linux

From: Michael Schuh (michael.schuh_at_gmail.com)
Date: 06/28/05

  • Next message: Chris Phillips: "Re: On recent crashes" 
    Date: Tue, 28 Jun 2005 18:29:59 +0200
To: Paul Mather <paul@gromit.dlib.vt.edu>

    Yes, i know that and i agree with them.
    that was the reason, why my disk is tiled on first physical Gigabyte for Swap,
    and the rest for the system....

    my target was to compare 2 Versions not 2 Os-Types like FreeBSD and Linux,
    but FreeBSD and FreeBSD, in cases RELENG_4 with RELENG_5.

    so that the little difference between the different places for files,
    remember i install everytime at the beginning of second Gig on disk,
    should be flawlessy and not make the results so big, that the RELENG_4
    has the double of speed from RELENG_5!

    best regards

    michael

    2005/6/28, Paul Mather <paul@gromit.dlib.vt.edu>:
    > On Tue, 2005-06-28 at 11:21 +0200, Roman Neuhauser wrote:
    > > # olli@lurza.secnetix.de / 2005-06-21 16:51:10 +0200:
    > > > For accurate measurements and comparisons, you have to make
    > > > sure to use _exactly_ the same physical location on the
    > > > disk.
    > >
    > > No you don't. You want to make a side-by-side comparison
    > > of two products, and if one of them underperforms, it just
    > > underperforms. You cannot use a poor location selection
    > > strategy in the driver as an excuse for poor operation.
    >
    > The point people are making is that location can have a significant
    > effect on performance, and so should not be dismissed out of hand.
    >
    > Here is what I get when I run diskinfo on one of the (somewhat elderly)
    > disks I use in my desktop system (this is a drive I use for data, and it
    > is idle):
    >
    > zappa# diskinfo -tv /dev/ad4
    > /dev/ad4
    > 512 # sectorsize
    > 25590620160 # mediasize in bytes (24G)
    > 49981680 # mediasize in sectors
    > 49585 # Cylinders according to firmware.
    > 16 # Heads according to firmware.
    > 63 # Sectors according to firmware.
    >
    > Seek times:
    > Full stroke: 250 iter in 5.159189 sec = 20.637 msec
    > Half stroke: 250 iter in 4.206125 sec = 16.825 msec
    > Quarter stroke: 500 iter in 7.151951 sec = 14.304 msec
    > Short forward: 400 iter in 2.794380 sec = 6.986 msec
    > Short backward: 400 iter in 4.135579 sec = 10.339 msec
    > Seq outer: 2048 iter in 0.332711 sec = 0.162 msec
    > Seq inner: 2048 iter in 0.363152 sec = 0.177 msec
    > Transfer rates:
    > outside: 102400 kbytes in 7.677977 sec = 13337 kbytes/sec
    > middle: 102400 kbytes in 9.151475 sec = 11189 kbytes/sec
    > inside: 102400 kbytes in 14.345492 sec = 7138 kbytes/sec
    >
    > Note how the transfer rate for the "outside" is almost twice that of the
    > "inside." Suppose I run tests on two different operating systems, one
    > of which resides in a partition on the "inside" portion and the other in
    > one on the "outside" portion. (Note that however good or bad it may be,
    > the "location selection strategy in the driver" can only lay out data
    > within the confines of the partition.) Now, I do a "dd" test and find
    > that the "outside" OS is almost twice as fast as the other. Would it be
    > wise to conclude that the slower OS is woefully inefficient compared to
    > the faster one? Suppose both tests turn out to take roughly the same
    > time. Should I conclude that the OS residing on the "inside" is just as
    > efficient as the other OS?
    >
    > Cheers,
    >
    > Paul.
    > --
    > e-mail: paul@gromit.dlib.vt.edu
    >
    > "Without music to decorate it, time is just a bunch of boring production
    > deadlines or dates by which bills must be paid."
    > --- Frank Vincent Zappa
    >
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