Re: [PATCH 0/2] netem: trace enhancement

[Stephen Hemminger <shemminger@linux-foundation.org>]

On Mon, 10 Dec 2007 15:32:14 +0100
Ariane Keller <ariane.keller@tik.ee.ethz.ch> wrote:

> I finally managed to rewrite the netem trace extension to use rtnetlink 
> communication for the data transfer for user space to kernel space.
> 
> The kernel patch is available here:
> http://www.tcn.hypert.net/tcn_kernel_2_6_23_rtnetlink
> 
> and the iproute patch is here:
> http://www.tcn.hypert.net/tcn_iproute2_2_6_23_rtnetlink
> 
> Whenever new data is needed the kernel module sends a notification to 
> the user space process. Thereupon the user space process sends a data 
> package to the kernel module.

I wonder if it wouldn't be possible to enhance/extend netlink
to use sendfile/splice to get the data.  It is rather more work than
needed for just this, but it would be useful for large configuration.

> I had to write a new qdisc_notify function (qdisc_notify_pid) since the 
> other was acquiring a lock, which we already hold in this situation.



> I hope everything works as expected and I'm looking forward for your 
> comments.
> 
> Thanks!
> Ariane


-- 
Stephen Hemminger <shemminger@linux-foundation.org>