From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joseph Gasparakis Subject: Re: vxlan/veth performance issues on net.git + latest kernels Date: Tue, 3 Dec 2013 17:29:06 -0800 (PST) Message-ID: References: <529DF340.70602@mellanox.com> <1386084620.30495.28.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Cc: Joseph Gasparakis , Or Gerlitz , Eric Dumazet , Jerry Chu , Or Gerlitz , Eric Dumazet , Pravin B Shelar , David Miller , netdev To: Alexei Starovoitov Return-path: Received: from mga09.intel.com ([134.134.136.24]:2413 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755412Ab3LDBLj (ORCPT ); Tue, 3 Dec 2013 20:11:39 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 3 Dec 2013, Alexei Starovoitov wrote: > On Tue, Dec 3, 2013 at 4:35 PM, Joseph Gasparakis > wrote: > > > > I was printing the gso_type in vxlan_xmit_skb(), right before > > iptunnel_xmit() gets called (I was focus UDPv4 encap only). Then I saw the > > gso_type was different when a VM was involved and when it was not > > (although I was transmitting exactly the same packet), and then I replaced > > my printk with something like skb_shinfo(skb)->gso_type = > for non-VM skb> and it all worked. > > > > Then I looked into what was different between the two gso_types and the > > only difference was that SKB_GSO_DODGY was set when Tx'ing from the VM. > > I am sure I could have been more delicate with the aproach, but hey, it > > worked for me. > > hmm. dodgy should be a normal path from vm. > kvm suppose to negotiate vnet_hdr for tap/macvtap and corresponding > driver will be remapping virtio_net_gso* flags into skb_gso_* flags > plus gso_dodgy. > Then would the fix be as simple as just unsetting the bit in vxlan? Because I am guessing that there is a bug somewhere where the combination of GSO_UDP_TUNNEL and GSO_DODGY. That would solve my problem, hopefully Or's too if it is the same.