[ofa-general] Re: [PATCH 00/10] Implement batching skb API

[Krishna Kumar2]

Stephen Hemminger <shemminger at linux-foundation.org> wrote on 07/20/2007
12:48:48 PM:

> You may see worse performance with batching in the real world when
> running over WAN's.  Like TSO, batching will generate back to back packet
> trains that are subject to multi-packet synchronized loss. The problem is
that
> intermediate router queues are often close to full, and when a long
string
> of packets arrives back to back only the first ones will get in, the rest
> get dropped.  Normal sends have at least minimal pacing so they are less
> likely do get synchronized drop.

Also forgot to mention in the previous mail, if performance is seen to be
dipping,
batching can be disabled on WAN's by:

echo 0 > /sys/class/net/<dev>/tx_batch_skbs

and use batching on local/site networks in that case.