Re: FreeBSD and poor ata performance

From: Kenneth Culver (culverk_at_sweetdreamsracing.biz)
Date: 10/15/04

  • Next message: Chris Neustrup: "gcc34" 
    Date: Fri, 15 Oct 2004 13:14:32 -0400
To: fandino@ng.fadesa.es

    Quoting fandino <fandino@ng.fadesa.es>:

    > Chris Howells wrote:
    >> On Friday 15 October 2004 09:57, fandino wrote:
    >>
    >>> I'm out of ideas, It doesn't matter if I use other PC or hard disks,
    >>> performance
    >>> sucks compared to Linux :-(
    >>
    >>
    >> OK, so you came to conclusion that "performance sucks" based on the
    >> the theoretical throughput figures using dd and /dev/zero?
    >>
    >> Why don't you try measuring real world performace, with real files,
    >> not somethig which is more than likely completely meaningless when
    >> two operating systems cache file system operations in different ways.
    >
    > well, my usage pattern is write a big file and few seconds later read
    > it. So my tests
    > were valid for the use of the computer.
    >
    > But you have reason, I must provide a more formal report. I redid all test
    > with bonnie++ and results shows Linux (56848 K/sec) two times faster than
    > FreeBSD (26347 K/sec)
    >
    > Any help will be appreciated!
    >
    >
    > Linux test (slackware 8.1, kernel 2.4.18, ext2 filesystem):

    This test isn't really a fair test either. The ext2 filesystem uses async io,
    and doesn't do any kind of journaling to ensure data integrity in the event of
    a crash. FreeBSD isn't using async, it uses softupdates. Because of this
    FreeBSD SHOULD be slower... but it'll be a lot more reliable than linux in the
    event of a power outage for example. The ext2 filesystem is extremely
    unreliable, and will almost always lose data when there's a crash or power
    outage.

    A better test would be to use ext3 as the filesystem (you can easily
    convert an
    ext2 filesystem to ext3, although I don't remember the name of the command to
    do it off the top of my head. In my own testing on a linux box, ext3 was about
    half as fast as ext2 in most of bonnie++'s tests, so I think this is
    why you're
    seeing the performance difference.

    Ken
    >
    > root@darkstar:/mnt# bonnie++ -s 2048 -u root
    > Using uid:0, gid:0.
    > Writing a byte at a time...done
    > Writing intelligently...done
    > Rewriting...done
    > Reading a byte at a time...done
    > Reading intelligently...done
    > start 'em...done...done...done...done...done...
    > Create files in sequential order...done.
    > Stat files in sequential order...done.
    > Delete files in sequential order...done.
    > Create files in random order...done.
    > Stat files in random order...done.
    > Delete files in random order...done.
    > Version 1.93c ------Sequential Output------ --Sequential Input-
    > --Random-
    > Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
    > --Seeks--
    > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
    > /sec %CP
    > darkstar 2G 951 97 35108 14 21964 11 1321 99 56848 16
    > 166.4 1
    > Latency 10024us 2203ms 896ms 16845us 9552us 4118ms
    > Version 1.93c ------Sequential Create------ --------Random
    > Create--------
    > darkstar -Create-- --Read--- -Delete-- -Create-- --Read---
    > -Delete--
    > files /sec %CP /sec %CP /sec %CP /sec %CP /sec
    > %CP /sec %CP
    > 16 2413 98 +++++ +++ +++++ +++ 2437 98 +++++
    > +++ 3822 90
    > Latency 9366us 37us 67us 18604us 23us 862us
    >
    > FreeBSD 5.3b7 (default filesystem):
    >
    > # bonnie++ -s 2048 -u root
    >
    > Using uid:0, gid:0.
    > Writing a byte at a time...done
    > Writing intelligently...done
    > Rewriting...done
    > Reading a byte at a time...done
    > Reading intelligently...done
    > start 'em...done...done...done...done...done...
    > Create files in sequential order...done.
    > Stat files in sequential order...done.
    > Delete files in sequential order...done.
    > Create files in random order...done.
    > Stat files in random order...done.
    > Delete files in random order...done.
    > Version 1.93c ------Sequential Output------ --Sequential Input-
    > --Random-
    > Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
    > --Seeks--
    > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP
    > /sec %CP
    > 2G 194 99 22506 12 10636 7 473 99 26347
    > 11 132.8 7
    > Latency 59164us 253ms 538ms 37925us 48156us 4554ms
    > Version 1.93c ------Sequential Create------ --------Random
    > Create--------
    > -Create-- --Read--- -Delete-- -Create--
    > --Read--- -Delete--
    > files /sec %CP /sec %CP /sec %CP /sec %CP /sec
    > %CP /sec %CP
    > 16 762 6 +++++ +++ 1449 8 760 5 +++++
    > +++ 1417 9
    > Latency 28352us 226us 22030us 30386us 139us 995us
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