Very low disk performance on 5.x

[Jonathan Noack]

On 5/2/2005 3:43 PM, Steven Hartland wrote:
> ----- Original Message ----- From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
>>> To eliminate various parts of the subsystems I've just tested:
>>> dd if=/dev/da0 of=/dev/null bs=64k count=100000
>>> Read: 220Mb/s
>>
>> This is a very interesting number to measure, you'll never
>> see anything else going faster than that.  Presumably
>> this is -current ?
> 
> Nope thats 5.4-STABLE this should be at the very least
> 260Mb/s as thats what the controller has been measured on
> linux at even through the FS.

Um... not quite.  That was the number you listed for S/W RAID5.  In that 
case you're not benchmarking the controller in the same way; the 
controller is just serving requests with no RAID processing overhead at 
all.  Could you get results for Linux that bypassed the filesystem but 
used H/W RAID5 like you are with FreeBSD?

>>> Compared with:
>>> dd if=/usr/testfile of=/dev/null bs=64k count=100000
>>> Read: 152Mb/s

-- 
Jonathan Noack | noackjr at alumni.rice.edu | OpenPGP: 0x991D8195
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