possible regression?

[Mag Gam]

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 <greg.freemyer at gmail.com> wrote:
> On Wed, Jan 19, 2011 at 10:36 PM, Mag Gam <magawake at gmail.com> wrote:
>> 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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