Re: FreeBSD 5.3b7and poor ata performance

From: Søren Schmidt <sos_at_DeepCore.dk>
Date: Mon, 18 Oct 2004 16:42:55 +0200
Kenneth Culver wrote:
> Quoting fandino <fandino_at_ng.fadesa.es>:
> 
>> Hello Kevin,
>>
>> Kevin Oberman wrote:
>>
>>>> Tests were done win bonnie++ 1.93c and the results were Linux two
>>>> times faster than FreeBSD using the same hardware.
>>>>
>>>> GNU/Linux 2.4.18 with ext2:               56848 K/sec
>>>> FreeBSD 5.3b7 with default fs:            26347 K/sec
>>>> FreeBSD 5.3b7 ata raid0* (two disks):     26131 K/sec
>>>> FreeBSD 5.3b7 geom stripe* (two disks):   30063 K/sec
>>>
>>>
>>>
>>> Are you comparing apples with apples? I believe that Linux mounts file
>>> systems as async by default. To compare with FreeBSD, you should use "-o
>>> async" when you mount. Of course, this is less reliable.
>>>
>>> Also, make sure that disk write-cache is enabled on both or disabled on
>>> both.
>>
>>
>> write-cache was enable on all tests and disks were in UDMA5 mode.
>>
>> In this new round of tests I add FreeBSD witch async and OpenBSD (always
>> using the same hardware). FreeBSD is by far, the worst throughput of all
>> (about 50% slower than others) :-?
>>
>> GNU/Linux 2.4.18 with ext2:               56848 K/sec
>> FreeBSD 5.3b7 with default fs:            26347 K/sec
>> FreeBSD 5.3b7 with default fs(async):     26566 K/sec
>> FreeBSD 5.3b7 ata raid0* (two disks):     26131 K/sec
>> FreeBSD 5.3b7 geom stripe* (two disks):   30063 K/sec
>> FreeBSD 5.3b7 geom stripe** (four disks): 31891 K/sec
>> OpenBSD 3.5 UFS fs:                       55277 K/sec
>>
>> * Each disk of the raid had a throughput of approx. 15000 K/sec
>> ** Each disk of the raid had a throughput of approx. 7500 K/sec
>> Each disk of the read split the throughput by half.
>>
>> How is possible that FreeBSD performs as bad?
>>
>>
> If you're still using the GENERIC kernel, that could explain it, and 
> judging
> from other emails I've seen from you, you're still using the GENERIC 
> kernel.

Right, and you should also use -U (softupdates) on you newfs line.

-- 

-Søren
Received on Mon Oct 18 2004 - 12:43:21 UTC

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