Subject: Re: [net-next PATCH 2/3] qdisc: bulk dequeue support for qdiscs with TCQ_F_ONETXQUEUE

From: Florian Westphal <[email-masked]>
Date: Wed, 3 Sep 2014 12:23:10 +0200

Jesper Dangaard Brouer <[email-masked]> wrote:
> On Tue, 02 Sep 2014 08:22:42 -0700
> Eric Dumazet <[email-masked]> wrote:
> 
> > On Tue, 2014-09-02 at 16:35 +0200, Jesper Dangaard Brouer wrote:
> > 
> > > This is crazy fast. This measurement is actually "too-high" as
> > > 10Gbit/s wirespeed is 14,880,952 (11049 pps too fast).
> > > 
> > > Signed-off-by: Jesper Dangaard Brouer <[email-masked]>
> > > ---
> > 
> > This looks buggy, you forgot about GSO.
> 
> The GSO check is (!skb->next), right(?)

No, you'd want to use skb_is_gso() helper.

> > Also, our idea was to use a byte count limit (aka BQL)
> 
> It makes sense. I will look into using the BQL limits.

Thanks Jesper.

> > If we dequeue 8 64KB packets, this patch adds head of line blocking,
> > which we fought hard.

Just to make sure: Using bql limits would resolve your HOL blocking
concerns, right?