Major performance hit with ToS setting

[Andrew Gallatin]

On 06/03/12 01:18, Kevin Oberman wrote:

> What can I say but that you are right. When I looked at the interface
> stats I found that the link overflow drops were through the roof! This
> confuses me a bit since the traffic is outbound and I woudl assume

Indeed, link overflow is incoming traffic that was dropped
due to lack of rx resources.  If you have flow control
disabled, it is drops simply due to lack of space in the
rx fifo.  If you have flow control enabled, link overflow
can include drops due to lack of host rx buffers as well.
For primarily WAN traffic, we suggest that flow control
be disabled (it is enabled by default).  With f/c disabled,
drops due to lack of rx buffers are counted as
dropped_no_[big|small]_buffer

At any rate, it is surprising to see link overflow increase
on an outgoing unidirectional test.  Is there other
incoming traffic that you might not have been aware of?
The only really unlikely thing I can think of is if something
is buffering tens of thousands of acks and dumping them
all at once.

Drew