[gentoo-user] pf-sources Kernel

[gentoo-user] pf-sources Kernel

[James]

Howdy!

Anyone running pf-sources?

AMD64?

Arm (Pandaboard{})?

Your insights and experiences are most welcome,
including your opinion of BFS...

[1] http://ck.kolivas.org/patches/bfs/bfs-faq.txt

curiously,
James

[gentoo-user] Re: pf-sources Kernel

[Nikos Chantziaras]

On 05/22/2011 05:36 PM, James wrote:
> Howdy!
>
> Anyone running pf-sources?
>
> AMD64?
>
> Arm (Pandaboard{})?
>
> Your insights and experiences are most welcome,
> including your opinion of BFS...
>
> [1] http://ck.kolivas.org/patches/bfs/bfs-faq.txt

I don't run pf-sources, but I run a BFS-patched gentoo-sources.  One of 
the reasons I use it is because of its support for the SCHED_ISO process 
priority, which is important for audio applications.  Otherwise, I would 
need to use a realtime-linux kernel, which is total overkill and I don't 
want to reboot into a different kernel just for an audio session.  Also, 
SCHED_ISO works for normal users so I don't have to launch stuff like 
jack-audio as root.

Another reason I use it is because my system becomes a bit more 
responsive with BFS (meaning the GUI - I use KDE).  You can do that with 
the mainline scheduler too, but it's not automatic; you have to set up 
the cgroups feature (creating different cgroups for different 
applications), and I never bothered.  It's up to the distro to provide a 
cgroups setup, but I don't know whether Gentoo or any other distro 
actually does it.  My guess is not.  Without a setup, users have to 
launch their applications from the terminal, which is kind of stupid. 
Launching them from the GUI will place them all in the same cgroup.

So BFS it is for me :-)

[gentoo-user] Re: pf-sources Kernel

[James]

Nikos Chantziaras <realnc <at> arcor.de> writes:


> I don't run pf-sources, but I run a BFS-patched gentoo-sources.  One of 
> the reasons I use it is because of its support for the SCHED_ISO process 
> priority, which is important for audio applications.  Otherwise, I would 
> need to use a realtime-linux kernel, which is total overkill and I don't 
> want to reboot into a different kernel just for an audio session.  Also, 
> SCHED_ISO works for normal users so I don't have to launch stuff like 
> jack-audio as root.

Very cool to know....

> Another reason I use it is because my system becomes a bit more 
> responsive with BFS (meaning the GUI - I use KDE).  

I've read this in quite a few place for 16 processors or less.
Interesting.
> So BFS it is for me 

I'm going to experiment with the pf-sources....
He seems to be up on the latest kernels and pathches,
much faster than any other kernel sources for Gentoo.


Thanks,
James

Re: [gentoo-user] pf-sources Kernel

[Alex Schuster]

James writes:

> Anyone running pf-sources?
> 
> AMD64?

Yes! Since two hours after I read your posting, never heard before of pf-
sources or BFS before.
And they run great! My system was somewhat unresponsive, especially when 
things like emerges were going on, video playback was stuttering, sometimes 
Amarok did this, too. Now, it's no problem any more. Well, activating Strigi 
desktop indexing and Nepomuk still slows things down, though.

> Your insights and experiences are most welcome,
> including your opinion of BFS...

It rocks!
But then, I have been running ck-sources before. And they also have the BFS 
patch. And it has been set in my .config. So, I should already have seen the 
benefits all the time.

Maybe this is all wishful thinking only? The system already performs much, 
much better since I added another 2G of RAM one week ago. Now I have 8G, and 
do not notice that much swapping any more. Although... right now,  swap is 
at 600M, and the system is swapping right now. Weird. I'm running rdiff-
backup, this seems to increase swap size. Maybe too much of the stuff it 
precesses is being cached? Swap is at 800M now.

	Wonko

[gentoo-user] Re: pf-sources Kernel

[Nikos Chantziaras]

On 05/25/2011 03:12 PM, Alex Schuster wrote:
> [...] Now I have 8G, and
> do not notice that much swapping any more. Although... right now,  swap is
> at 600M, and the system is swapping right now. Weird. I'm running rdiff-
> backup, this seems to increase swap size. Maybe too much of the stuff it
> precesses is being cached? Swap is at 800M now.

You can tweak this in /etc/sysctl.conf:

   vm.swappiness = 30

Or maybe 20.  The default is 60.  IMO way too high for desktop systems.