# optimizing the kernel configuration

## printf

i recently switched to the latest pf sources (2.6.38), i know it is not supported officially by gentoo, but my question also covers kernel in general.

i followed both pappy's kernel seeds and tried to turn on most of the things that the pf pathes introduce, but im still not sure if everything runs at full potential

i have an IBM thinkpad T30 with a single core pentium 4-mobile, and i mainly use it for general desktop usage

my main problem is that i didnt get the INSTANT response that i hoped to get when i enabled BFS, also im not even sure that i have all the new .38 features enabled that supposed to increase performance (like the new file-system caching or the process grouping - dont know if this works well with BFS)

thanks

here is my config:

http://pastebin.com/YkWyYBPULast edited by printf on Wed Apr 27, 2011 4:01 pm; edited 1 time in total

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## wswartzendruber

1. Pastebin is your friend.

2. How do you expect to have the responsiveness when CONFIG_CGROUPS is disabled?

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## printf

sorry, next time will use pastebin.

dont know how outdated is pappy's kernel seeds, but i have read this on the site (http://kernel-seeds.org/settings-01.html):

Control Group support --->

Important!Consider both of these settings as poison to your computer. While the idea has merit, at the time of this writing, there remain no userspace programs to interface with the setup. As such, these settings and their analogues tend to slow systems down. For this reason, these settings are turned off by default, and their use is highly discouraged. Kernel seeds are about speed and efficiency, and the above settings are neither fast or efficient.

or this one refers to something else?

and does it not conflict with BFS?

or exists there other site with a very detailed kernel configuration description?

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## depontius

 *wswartzendruber wrote:*   

> 
> 
> 2. How do you expect to have the responsiveness when CONFIG_CGROUPS is disabled?

 

Until recently, I have only ever seen CGROUPS slow things down for me.  Turning it off has been one of the first things I do on a new kernel.  At work I need to run FC13/RH6, and there's a "speedy200" rpm that implements the userspace equivalent of the built-in autogroup thing that was added with 2.6.38.  On my Gentoo systems I'm either running 2.6.38 with autogroups or something earlier with cgroups off.

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## wswartzendruber

I'm talking about the wrong option.   :Embarassed: 

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## illuminated

Are there any other alternatives besides papy's kernel seeds ?

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## krinn

sure build your own kernel, it's not hard, and for a start, you can check out this help (the kernel section). http://swift.siphos.be/linux_sea/

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## wswartzendruber

No, wait, I was talking about the right option.  Inside CONFIG_CGROUPS is another option: CONFIG_CGROUP_SCHED.  And that's the scheduler that utilizes control groups to make things more responsive.

EDIT:  Er, I think.

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## printf

 *wswartzendruber wrote:*   

> No, wait, I was talking about the right option.  Inside CONFIG_CGROUPS is another option: CONFIG_CGROUP_SCHED.  And that's the scheduler that utilizes control groups to make things more responsive.
> 
> EDIT:  Er, I think.

 

and that works with BFS?

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## printf

 *krinn wrote:*   

> sure build your own kernel, it's not hard, and for a start, you can check out this help (the kernel section). http://swift.siphos.be/linux_sea/

 

i think he was referring to the tutorial, not the pre-made config files

i never used the config files, only used the settings tutorial and it is helpful but some information is missing or the author is not always 100% sure of things

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## wswartzendruber

 *printf wrote:*   

>  *wswartzendruber wrote:*   No, wait, I was talking about the right option.  Inside CONFIG_CGROUPS is another option: CONFIG_CGROUP_SCHED.  And that's the scheduler that utilizes control groups to make things more responsive.
> 
> EDIT:  Er, I think. 
> 
> and that works with BFS?

 

Go into your block scheduler options and tell it to plug into control groups.  It's a new option.  That, I believe, is independent of the chosen FS.

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## Aquous

BFS does not use, or care about, control groups. See here: http://ck.kolivas.org/patches/bfs/sched-BFS.txt

 *wswartzendruber wrote:*   

> That, I believe, is independent of the chosen FS.

 What does that have to do with BFS?

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## wswartzendruber

For some reason I read BTRFS.   :Embarassed: 

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## mbar

 *Aquous wrote:*   

> BFS does not use, or care about, control groups. See here: http://ck.kolivas.org/patches/bfs/sched-BFS.txt
> 
>  *wswartzendruber wrote:*   That, I believe, is independent of the chosen FS. What does that have to do with BFS?

 

Yep, BFS doesn't care about cgroups, but BFQ does  :Wink: 

http://algo.ing.unimo.it/people/paolo/disk_sched/

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## printf

currently i have BFQ enabled (it was patched in by the pf-sources, thought i should try it)

should i use process grouping or BFQ (or the two go together?)

if i should switch to process grouping, which options should i enable?

sorry for the questions but my problem is that it is very hard to find exactly the things you want when configuring a kernel

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