This is just for curiosity.  I think its strange this is occurring
thats all. It did not happen in the older kernels but its happening on
the newer versions. Possibly there maybe more like this.


On Sun, Jan 23, 2011 at 10:31 PM, Greg Freemyer [off-list ref] wrote:

On Wed, Jan 19, 2011 at 10:36 PM, Mag Gam [off-list ref] wrote:

quoted

Running on Redhat 5.1 if I do,
dd bs=1024 count=1000000 if=/dev/zero of=/dev/null

I get around 30Gb/sec

However, when I do this with 2.6.37 I get close to 5GB/sec

Is there anything new in the kernel?

TIA

Mag,

assuming you really meant 30 GB/sec vs. 5 GB/sec and there are no
errors in your test, why do you care?

ie. There is no comm or storage device I use that can run 5 GB/sec.
In fact 1 GB/sec is pretty fast for most storage.

Or is this more a curiosity thing?

The performance loss could be /dev/zero, dd, or /dev/null. ?I would
guess /dev/zero which is why I wonder what you need to track this
down. ?A performance limited /dev/zero at 5 GB/sec is not a big issue
for most uses.

Greg
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