# Kworker eats 99% disk performance

## drhouse123

Hi folks!

When i'd run  something like 'dd if=/dev/zero of=file bs=1G' my filemanager fully freezed. 

When i looked to iotop there was kworker process, that "eats" 99% of disk i/o performance.

Is it iowait_bug or something else or default behavior by design?

Here also compiling in chroot and nepomuk, but they're doesn't affect to disk performance too much as above command.

Here a screenshoot (My system interface on Russian)

http://i.imgur.com/u7yNGgE.pngLast edited by drhouse123 on Wed Oct 16, 2013 10:31 pm; edited 1 time in total

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## cwr

A 1G blocksize is _very_ odd; I'd expect nothing, or 512, or 4096.

What happens if you drop the blocksize argument?  Obviously

you'll fill the partition, but I take it that's the object of the exercise.

Will

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## drhouse123

 *cwr wrote:*   

> A 1G blocksize is _very_ odd; I'd expect nothing, or 512, or 4096.
> 
> What happens if you drop the blocksize argument?  Obviously
> 
> you'll fill the partition, but I take it that's the object of the exercise.
> ...

 

I did  dd if=/dev/zero of=file bs=512K count=15000 but same thing as previously.

I did dd if=/dev/zero of=file bs=4096K count=15000

But nothing, no changes.

Creating fixed VDI image for Virtualbox did and does same worst thing as dd   :Crying or Very sad: 

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## drhouse123

It seems that worst thing is not appear in Debian Unstable with 3.10.x kernel

 :Sad: 

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## zeronullity

 *drhouse123 wrote:*   

> It seems that worst thing is not appear in Debian Unstable with 3.10.x kernel
> 
> 

 

The commands your using are identical on both OS for testing? I.E. Your not trying to use a loop drive for one test.. and a different drive for another. If your using

/tmp for testing make sure one OS isn't using tmpfs and the other the root partition of your sata drive etc. Double check the loaded controller drivers are the same in both Kernels.And check kernel settings and what sysctl might be loading at startup. I would say controller issue or drive type your writing to.

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