netdev - Re: [PATCH] bgmac: Remove all offloading features, including GRO.

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Message-ID: <1505522322.3726.0.camel@gmail.com>
Date:   Fri, 15 Sep 2017 17:38:42 -0700
From:   rosenp@...il.com
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH] bgmac: Remove all offloading features, including GRO.

I have not. Unfortunately I own no gigabit hardware to test this on.
The MIPS CPU runs at 300MHz on my unit.

On Fri, 2017-09-15 at 17:34 -0700, Eric Dumazet wrote:
> On Fri, 2017-09-15 at 17:23 -0700, Rosen Penev wrote:
> > On a linksys E1200v1 (actually a crossflashed E1000v2), the
> > offloading features give no measurable benefit to speed or latency.
> > Furthermore, disabling GRO actually improves iperf performance by a
> > whoppimg 3mbps. Results:
> > 
> > Currently:
> > 
> > v2: Changed napi_gro_receive to netif_receive_skb. Seems to have an
> > identical result.
> > 
> > Signed-off-by: Rosen Penev <rosenp@...il.com>
> > ---
> >  drivers/net/ethernet/broadcom/bgmac.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/net/ethernet/broadcom/bgmac.c
> > b/drivers/net/ethernet/broadcom/bgmac.c
> > index 48d672b204a4..1fb0053aeee7 100644
> > --- a/drivers/net/ethernet/broadcom/bgmac.c
> > +++ b/drivers/net/ethernet/broadcom/bgmac.c
> > @@ -483,7 +483,7 @@ static int bgmac_dma_rx_read(struct bgmac
> > *bgmac, struct bgmac_dma_ring *ring,
> >  			skb->protocol = eth_type_trans(skb, bgmac-
> > >net_dev);
> >  			bgmac->net_dev->stats.rx_bytes += len;
> >  			bgmac->net_dev->stats.rx_packets++;
> > -			napi_gro_receive(&bgmac->napi, skb);
> > +			netif_receive_skb(skb);
> >  			handled++;
> >  		} while (0);
> >  
> 
> And have you tested 1Gbit link speed ?
> ( Or 2.5 Gbit link speed )
> 
> If you want to disable GRO on your host, fine : you can use ethtool
> -K
> 
> 
>