Re: [RFC] napi: limit GRO latency

Stephen Hemminger
2012-10-08T19:13:31Z

On Mon, 08 Oct 2012 15:10:35 -0400 (EDT)
David Miller <davem@davemloft.net> wrote:

> From: Stephen Hemminger <shemminger@vyatta.com>
> Date: Mon, 8 Oct 2012 11:58:35 -0700
>
> > Limit the latency of pending GRO in NAPI processing to 2*HZ.
> > When the system is under heavy network load, NAPI will go into
> > poll mode via soft irq, and only stay in the loop for
> > two jiffies. If this occurs, process the GRO pending list
> > to make sure and not delay outstanding TCP frames for too long.
> >
> > Rearrange the exit path to get rid of unnecessary goto logic.
> >
> > Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
>
> Did you see Eric's patch I just applied which limits it to 1ms?

Think this is a different problem.
After leaving softirq, it may be a long time until
ksoftirqd is run which is a different problem.