224 lines of kernel code to boost the Linux experience - would this apply to Android?

[sarreq]

http://www.phoronix.com/scan.php?pag...37_video&num=1

I just saw this and was wondering if this patch would/could apply to the Android kernel as well. any kernel programmers out there who might know/be willing to find out?

[KillerVamp]

From what I can tell it affects how the CPU is handled and processing time, so theoretically yes. But as android is a Java Stack, or basically a virtual machine, I am not entirely sure.

[sarreq]

yes, but Dalvik runs on top of the kernel, right? if the kernel can be boosted, so would everything running on top of it, like Dalvik.

[sarreq]

no one? p3? slayher? chevy? bueller? bueller? bueller?

[meishkov]

This sounds like a great idea. I'd love if some research could get done on this...I'd be willing to help out and test some stuff.

[sarreq]

an alternative which can be used now without a new kernel.
same question, could this be adapted to android?


Text quoted because the page seems to freeze my firefox

Alternative To The "200 Lines Kernel Patch That Does Wonders" Which You Can Use Right Away

Phoronix recently published an article regarding a ~200 lines Linux Kernel patch that improves responsiveness under system strain. Well, Lennart Poettering, a RedHat developer replied to Linus Torvalds on a maling list with an alternative to this patch that does the same thing yet all you have to do is run 2 commands and paste 4 lines in your ~/.bashrc file. I know it sounds unbelievable, but apparently someone even ran some tests which prove that Lennart's solution works. Read on!

Basically, Lennart explains you have to add this to your ~/.bashrc file (important: this won't work on Ubuntu. See instructions for Ubuntu further down the post!):

if [ "$PS1" ] ; then              mkdir -m 0700 /sys/fs/cgroup/cpu/user/$$            echo $$ > /sys/fs/cgroup/cpu/user/$$/tasks    fi

And run the following commands as super user:

mount -t cgroup cgroup /sys/fs/cgroup/cpu -o cpu mkdir -m 0777 /sys/fs/cgroup/cpu/user

Further more, a reply to Lennart's email states that his approach is actually better then the actual Kernel patch

I've done some tests and the result is that Lennart's approach seems to work best. It also _feels_ better interactively compared to the vanilla kernel and in-kernel cgrougs on my machine. Also it's really nice to have an interface to actually see what is going on. With the kernel patch you're totally in the dark about what is going on right now.

-Markus Trippelsdorf

The reply also includes some benchmarks you can see @ LKML: Markus Trippelsdorf: Re: [RFC/RFT PATCH v3] sched: automated per tty task groups

Use it in Ubuntu


Update (November 24): because many people had trouble following the instructions below, there is now a script that automatically does everything for you. See: Script To Automatically Apply the "200 Lines Kernel Patch" Alternative In Ubuntu


To use Lennart's solution in Ubuntu (not tested - thanks to Lsh for this), you have to replace "/sys/fs" with "/dev". So you would have to add the following commands in your /etc/rc.local (open it with: sudo gedit /etc/rc.local) file, above the "exit 0" line:

mkdir -p /dev/cgroup/cpu mount -t cgroup cgroup /dev/cgroup/cpu -o cpu mkdir -m 0777 /dev/cgroup/cpu/user echo "/usr/local/sbin/cgroup_clean" > /dev/cgroup/cpu/release_agent

and make it executable:

sudo chmod +x /etc/rc.local

And then add the following to your ~/.bashrc file (to open it: gedit ~/.bashrc):

if [ "$PS1" ] ; then      mkdir -p -m 0700 /dev/cgroup/cpu/user/$$ > /dev/null 2>&1    echo $$ > /dev/cgroup/cpu/user/$$/tasks    echo "1" > /dev/cgroup/cpu/user/$$/notify_on_release fi

Run the following command:

sudo gedit /usr/local/sbin/cgroup_clean

And paste this:

#!/bin/sh if [ "$*" != "/user" ]; then rmdir /dev/cgroup/cpu/$* fi
then save the file and make it executable:
sudo chmod +x /usr/local/sbin/cgroup_clean

And finally, restart the computer or manually run the /etc/rc.local file ("sudo /etc/rc.local").


Update November 19: The above instructions have been updated again to "really" automatically remove empty cgroups (thank to Ricardo Ferreira using the instructions he sent.).



Update 2: if you don't want to follow the manual steps above, you can use some patched kernels (Warning: use these at your own risk!!!) for Ubuntu 10.10:

If you want to go even further and install a patched Kernel, you can download a "200 lines" patched Kernel (for 64bit only!) from HERE (thanks to accumulator @ Phoronix forums).


Also, WebUpd8 reader Scott Franke shared a Kernel he patched with bfs with which he says he gets better performance then with the "200 lines patch". Download (also 64bit only!): 1 and 2 (both .deb files required).


Both of the above 2 Kernels are for Ubuntu 10.10 only! Use them at your own risk!



Read the discussion @ LKML: Markus Trippelsdorf: Re: [RFC/RFT PATCH v3] sched: automated per tty task groups | via Habrahabr.ru (thanks to Lsh)

[meishkov]

Bump
Is somebody maybe working on this?

[furbearingmammal]

Why don't you go post in the Developers section or ask for the thread to be moved there? That might speed things along. A PM to tanknspank might not be out of the question, either. He's very knowledgeable about the Android system's code.