Messages in this thread Patch in this message | | | Subject | Re: Driver has suspect GRO implementation, TCP performance may be compromised. | From | Eric Dumazet <> | Date | Tue, 28 May 2019 10:18:59 -0700 |
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On 5/28/19 8:42 AM, Paul Menzel wrote: > Dear Linux folks, > > > Occasionally, Linux outputs the message below on the workstation Dell > OptiPlex 5040 MT. > > TCP: net00: Driver has suspect GRO implementation, TCP performance may be compromised. > > Linux 4.14.55 and Linux 5.2-rc2 show the message, and the WWW also > gives some hits [1][2]. > > ``` > $ sudo ethtool -i net00 > driver: e1000e > version: 3.2.6-k > firmware-version: 0.8-4 > expansion-rom-version: > bus-info: 0000:00:1f.6 > supports-statistics: yes > supports-test: yes > supports-eeprom-access: yes > supports-register-dump: yes > supports-priv-flags: no > ``` > > Can the driver e1000e be improved? > > Any idea, what triggers this, as I do not see it every boot? Download > of big files? > Maybe the driver/NIC can receive frames bigger than MTU, although this would be strange.
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c61edd023b352123e2a77465782e0d32689e96b0..cb0194f66125bcba427e6e7e3cacf0c93040ef61 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -150,8 +150,10 @@ static void tcp_gro_dev_warn(struct sock *sk, const struct sk_buff *skb, rcu_read_lock(); dev = dev_get_by_index_rcu(sock_net(sk), skb->skb_iif); if (!dev || len >= dev->mtu) - pr_warn("%s: Driver has suspect GRO implementation, TCP performance may be compromised.\n", - dev ? dev->name : "Unknown driver"); + pr_warn("%s: Driver has suspect GRO implementation, TCP performance may be compromised." + " len %u mtu %u\n", + dev ? dev->name : "Unknown driver", + len, dev ? dev->mtu : 0); rcu_read_unlock(); } }
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