# How to downgrade kernel (2.6.31->2.6.29)? [Solved]

## CaptainBlood

Hi all,

Wishing to evaluate XEN performance on a 2.6.31-r10 Gentoo install, it seems preferable to downgrade to kernel 2.6.29.

What is the best (cleanest???) way to proceed?

Is there anything I should especially be careful about ?

I prefer to ask for recommendation first instead to risk to mess up the all thing. Right time for a partition backup, I guess  :Laughing: !

Thanks for your attention.Last edited by CaptainBlood on Wed Mar 17, 2010 3:28 pm; edited 1 time in total

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## depontius

Just emerge the kernel you want.  When portage brings in sources for a new kernel, it doesn't delete the old automatically.  Build your desired kernel, configure it in grub, and you're set to go.  If you want, you can keep tracking the newest kernel on a test (non-default in grub) basis to see if your performance regression improves, at some point.  I've never messed with xen-sources, but from time to time I've even bounced between gentoo, vanilla, and tuxonice sources for my kernels.

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## CaptainBlood

Thanks for your reply. I'm probably doing it the wrong way  :Embarassed:  since :

```
emerge -p gentoo-sources-2.6.29
```

unfortunatly replies

```
!!! 'gentoo-sources-2.6.29' is not a valid package atom.
```

Can you help ?

Thanks for your attention and support.

NB it's on amd64.

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## gerard27

It should read

```

emerge -p =gentoo-sources-2.6.29-r5
```

The complete name should be used.

Gerard.

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## bendeguz

 *CaptainBlood wrote:*   

> Thanks for your reply. I'm probably doing it the wrong way  since :
> 
> ```
> emerge -p gentoo-sources-2.6.29
> ```
> ...

 

http://packages.gentoo.org/package/sys-kernel/gentoo-sources

You have to specify whether is is r5 or r6...

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## gerard27

The "=" is indispensable!

Gerard.

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## CaptainBlood

Thanks for your reply.

My bad  :Embarassed: ! noob silliness  :Laughing:  ...

It's time to close this post.

Guess a long way to go until XEN, still.

Will open a new thread when required  :Wink: .

Thanks to you all for your attention, interest and support.

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