Andi Kleen wrote:

On Thu, Jan 31, 2008 at 10:26:19AM -0800, Rick Jones wrote:

quoted

Andi Kleen wrote:

quoted

TSO interacts badly with many queueing disciplines because they rely on 
reordering packets from different streams and the large TSO packets can 
make this difficult. This patch disables TSO for sockets that send over 
devices with non standard queueing disciplines. That's anything but noop 
or pfifo_fast and pfifo right now.

Does this also imply that JumboFrames interacts badly with these qdiscs? 
Or IPoIB with its 65000ish byte MTU?

Correct. Of course it is always relative to the link speed. So if your
link is 10x faster and your packets 10x bigger you can get similarly
smooth shaping.

So, at what timescale do people using these qdiscs expect things to 
appear "smooth?"  64KB of data at GbE speeds is something just north of 
half a millisecond unless I've botched my units somewhere.

rick jones