2.6.18-1.2189.fc5: Decreased data throughput?

[Arjan van de Ven]

On Wed, 2006-10-11 at 12:41 +0200, Mostafa Afgani wrote:
> Hi,
> 
> In order to use the JMicron controller on my Asus P5B, I decided to
> try out 2.6.18-1.2189.fc5 kernel from updates-testing. Prior to this I
> was stuck running the 2.6.15-1.2054_FC5 kernel due to stability
> issues.
> 
> For the HDD, I am using the ICH8 sata ports running in AHCI mode. To
> test throughput, I ran the following command:
> 
> $ dd if=/dev/zero of=/tmp/dummy bs=100k count=10
> 
> With the 2054 kernel, I see a throughput of around 500 MB/s. With the
> 2189, that value is almost half at around 230 MB/s.

since a normal disk can maybe do 80Mbyte/sec on a sunny day while going
downhill.. it looks like your benchmark is measuring something else
(like VM caching policy).... if you want to measure disk throughput you
might want to consider using another benchmark; I tend to use tiobench
(tiobench.sf.net) for things like this...