FreeBSD and poor ata performance

[Kenneth Culver]

Quoting fandino <fandino at 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 at 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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