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SubjectRe: SATA Harddisk speed drop of 100 MB/s
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On Sat, Jun 23, 2007 at 04:59:06AM +0200, Carlo Wood wrote:
> Just one kernel version? The problem here is in every
> kernel revision after 551c012d7eea3dc5ec063c7ff9c718d39e77634f
>
> 2.6.20-rc2,rc3,rc4,rc5,rc6,rc7 ... 2.6.20 ... 2.6.21 ... 2.6.22-rc5
>
> noop:
> Timing buffered disk reads: 254 MB in 3.00 seconds = 84.66 MB/sec
>
> anticipatory:
> Timing buffered disk reads: 252 MB in 3.02 seconds = 83.43 MB/sec
>
> deadline:
> Timing buffered disk reads: 258 MB in 3.02 seconds = 85.41 MB/sec
>
> cfq:
> Timing buffered disk reads: 194 MB in 3.03 seconds = 64.06 MB/sec
>
> The normal value is cfq. So, all other schedulars are somewhat faster,
> but still far from the correct 165 MB/s.

How do you know 165MB/s is correct?

As for 10k rpm being faster, well remember rotation speed _and_ areal
density is what gives transfer rate. a 750GB 7200rpm is likely able to
have a higher throughput than a 73GB 10k rpm drive since more bits pass
by the head in any given unit of time on the larger drive. The 7200 rpm
has a slower average access time though.

--
Len Sorensen
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