Re: README: [PATCH RFC 11/11] net/mlx5e: XDP TX xmit more


Jesper Dangaard Brouer
 

On Tue, 13 Sep 2016 08:58:30 -0700
Eric Dumazet <eric.dumazet@...> wrote:

We also care about icache pressure, and GRO/TSO already provides
bundling where it is applicable, without adding insane complexity in
the stacks.
Sorry, I cannot resist. The GRO code is really bad regarding icache
pressure/usage, due to how everything is function pointers calling
function pointers, even if the general case is calling the function
defined just next to it in the same C-file (which usually cause
inlining). I can easily get 10% more performance for UDP use-cases by
simply disabling the GRO code, and I measure a significant drop in
icache-misses.

Edward's solution should lower icache pressure.

--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
Author of http://www.iptv-analyzer.org
LinkedIn: http://www.linkedin.com/in/brouer

Join iovisor-dev@lists.iovisor.org to automatically receive all group messages.