Adding new packet scheduler

Adding new packet scheduler

[Josh Clark]

Hi everyone,

I'm a student at NC State University, and I'm working on a project to
implement some new classful AQM algorithms and test their
effectiveness. However, I'm getting hung up on how to get the new
algorithm set up in the kernel.

>From what I've looked at, it looks like I need to add my code to
/net/sched/, and edit both the Kconfig and the Makefile to be able to
add my code as another module.

Finally, in order to use the new scheduler, I need to select it using
the tc command. What do I need to do to add my algorithm to the tc
command options?

Any insight, articles, READMEs, or criticism you have for me is welcome.

Thank you for all your help!




-Josh Clark

Re: Adding new packet scheduler

[Cong Wang]

On Mon, Oct 20, 2014 at 10:32 AM, Josh Clark <jcinma@gmail.com> wrote:
> Hi everyone,
>
> I'm a student at NC State University, and I'm working on a project to
> implement some new classful AQM algorithms and test their
> effectiveness. However, I'm getting hung up on how to get the new
> algorithm set up in the kernel.
>
> From what I've looked at, it looks like I need to add my code to
> /net/sched/, and edit both the Kconfig and the Makefile to be able to
> add my code as another module.

Basically yes, take a look at:
http://lwn.net/Articles/577208/

>
> Finally, in order to use the new scheduler, I need to select it using
> the tc command. What do I need to do to add my algorithm to the tc
> command options?

Read the existing qdisc's in tc, for example:
http://git.kernel.org/cgit/linux/kernel/git/shemminger/iproute2.git/tree/tc/q_fq.c

Re: Adding new packet scheduler

[Josh Clark]

On Mon, Oct 20, 2014 at 1:37 PM, Cong Wang <cwang@twopensource.com> wrote:
> On Mon, Oct 20, 2014 at 10:32 AM, Josh Clark <jcinma@gmail.com> wrote:
>> Hi everyone,
>>
>> I'm a student at NC State University, and I'm working on a project to
>> implement some new classful AQM algorithms and test their
>> effectiveness. However, I'm getting hung up on how to get the new
>> algorithm set up in the kernel.
>>
>> From what I've looked at, it looks like I need to add my code to
>> /net/sched/, and edit both the Kconfig and the Makefile to be able to
>> add my code as another module.
>
> Basically yes, take a look at:
> http://lwn.net/Articles/577208/
>
>>
>> Finally, in order to use the new scheduler, I need to select it using
>> the tc command. What do I need to do to add my algorithm to the tc
>> command options?
>
> Read the existing qdisc's in tc, for example:
> http://git.kernel.org/cgit/linux/kernel/git/shemminger/iproute2.git/tree/tc/q_fq.c

That all makes a lot of sense. What do I need to do to apply these
patches on a live system? I have access to a network made of virtual
machines with standard Ubuntu 14.04, to which I have SSH access.
There's no way for me to upload a different image to use.

Re: Adding new packet scheduler

[Cong Wang]

On Mon, Oct 20, 2014 at 10:51 AM, Josh Clark <jcinma@gmail.com> wrote:
>
> That all makes a lot of sense. What do I need to do to apply these
> patches on a live system? I have access to a network made of virtual
> machines with standard Ubuntu 14.04, to which I have SSH access.
> There's no way for me to upload a different image to use.

https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt

Q: How do the changes posted to netdev make their way into Linux?

A: There are always two trees (git repositories) in play.  Both are driven
   by David Miller, the main network maintainer.  There is the "net" tree,
   and the "net-next" tree.  As you can probably guess from the names, the
   net tree is for fixes to existing code already in the mainline tree from
   Linus, and net-next is where the new code goes for the future release.
   You can find the trees here:

http://git.kernel.org/?p=linux/kernel/git/davem/net.git
http://git.kernel.org/?p=linux/kernel/git/davem/net-next.git

Re: Adding new packet scheduler

[Dave Taht]

On Mon, Oct 20, 2014 at 10:32 AM, Josh Clark <jcinma@gmail.com> wrote:
> Hi everyone,
>
> I'm a student at NC State University, and I'm working on a project to
> implement some new classful AQM algorithms and test their
> effectiveness. However, I'm getting hung up on how to get the new
> algorithm set up in the kernel.
>
> From what I've looked at, it looks like I need to add my code to
> /net/sched/, and edit both the Kconfig and the Makefile to be able to
> add my code as another module.
>
> Finally, in order to use the new scheduler, I need to select it using
> the tc command. What do I need to do to add my algorithm to the tc
> command options?
>
> Any insight, articles, READMEs, or criticism you have for me is welcome.
>
> Thank you for all your help!

To give you an idea here are some currently out of tree, out of date,
and highly experimental codel patches of mine
that add in some new qdiscs, and patch the right places, with the
exception of patching include/uapi/linux/pkt_sched.h (which exports
the stuff to userspace)

https://github.com/dtaht/cerowrt-3.10/blob/master/target/linux/generic/patches-3.10/680-codel-add-experimental-codel-and-fq_codel-versions.patch

to add stuff to tc, you patch the iproute2 utility to match what is
exported from pkt_sched.h.




>
>
>
> -Josh Clark
> --
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-- 
Dave Täht

thttp://www.bufferbloat.net/projects/bloat/wiki/Upcoming_Talks