Re: [dpdk-users] Unable to merge packets using GRO feature

["Hu, Jiayu" <jiayu.hu@intel.com>]

Hi,

Can you tell me what's the NIC type of the GRO-enabled port?

Since GRO library uses mbuf->packet_type to parse packet headers, applications
need to fill this value before calling GRO reassembly APIs. Otherwise, the GRO
can't work correctly.

In csum forwarding engine of testpmd, packet_type is filled by NIC drivers. The csum
forwarding engine won't set this value. So if your NIC doesn’t support to parse packet
types, the value of packet_type is 0 and GRO can't work correctly.

BRs,
Jiayu

> -----Original Message-----
> From: Wisam Monther [mailto:wisamm@mellanox.com]
> Sent: Tuesday, August 22, 2017 9:25 PM
> To: Hu, Jiayu <jiayu.hu@intel.com>
> Cc: users@dpdk.org; Raslan Darawsheh <rasland@mellanox.com>; Shahaf
> Shuler <shahafs@mellanox.com>
> Subject: RE: Unable to merge packets using GRO feature
> 
> Yes it is,
> The fragmented packets comes from port1 / NIC b from machine A to port 1
> in NIC A for machine b
> So it's received on the port '1', which is configured gro active on this port.
> 
> Best regards,
> Wisam Jaddo
> 
> -----Original Message-----
> From: Hu, Jiayu [mailto:jiayu.hu@intel.com]
> Sent: Tuesday, August 22, 2017 4:21 PM
> To: Wisam Monther
> Cc: users@dpdk.org; Raslan Darawsheh; Shahaf Shuler
> Subject: RE: Unable to merge packets using GRO feature
> 
> Hi,
> 
> > -----Original Message-----
> > From: Wisam Monther [mailto:wisamm@mellanox.com]
> > Sent: Tuesday, August 22, 2017 7:07 PM
> > To: Hu, Jiayu <jiayu.hu@intel.com>
> > Cc: users@dpdk.org; Raslan Darawsheh <rasland@mellanox.com>; Shahaf
> > Shuler <shahafs@mellanox.com>
> > Subject: RE: Unable to merge packets using GRO feature
> >
> > Hey Jiayu,
> >
> > Thank you for your reply.
> > I tried what you said with the csum at fwd mode.
> > Even so the GRO didn't works fine.
> >
> > I even tested with a new methodology.
> > Two machines with two different nic for each.
> > The methodology that I used to test it is described in the attached file.
> >
> > What I did from gro side:
> > """
> > testpmd>gro on 1
> 
> Does the port number of NIC A in machine B is '1'? When you enable GRO for
> port '1', Testpmd only tries to merge packets received from port '1'.
> 
> BRs,
> Jiayu
> 
> > Testpmd>set fwd csum
> > Testpmd>start
> > """
> > And the packet with correct dst mac.
> >
> > Best regards,
> > Wisam Jaddo
> > -----Original Message-----
> > From: Jiayu Hu [mailto:jiayu.hu@intel.com]
> > Sent: Monday, August 21, 2017 12:14 PM
> > To: Wisam Monther
> > Cc: Thomas Monjalon; users@dpdk.org; Raslan Darawsheh; Shahaf Shuler
> > Subject: Re: Unable to merge packets using GRO feature
> >
> > Hi,
> >
> > On Mon, Aug 21, 2017 at 07:25:23AM +0000, Wisam Monther wrote:
> > > Hello Guys,
> > >
> > >
> > >
> > > I hope this finds you well, I’m trying to test the GRO feature. But
> > > I’m stuck with this scenario.
> > >
> > > As you know, GRO is only support TCP_IPV4 packet until now.
> > >
> > > So I’m trying to test the basic functionality of the feature, as following:
> > >
> > > Start testpmd:
> > >
> > > “””
> > >
> > > ./x86_64-native-linuxapp-gcc/build/app/test-pmd/testpmd -n 4  -w
> > > 00:0a.0  -w
> > > 00:09.0 --  --burst=64 --mbcache=512 --portmask 0xf -i  --txd=512
> > > --rxd=512
> > > --nb-cores=9  --rxq=2 --txq=2 --txqflags=0
> > >
> > > “””
> > >
> > >
> > >
> > > Then enable GRO at the two ports:
> > >
> > > “””
> > >
> > > Testpmd>gro on 0
> > >
> > > Testpmd>gro on 1
> >
> > When use GRO in testpmd, there are following things to notice:
> >
> > 1. In testpmd, GRO is supported by csum forwarding engine. Therefore,
> > please use 'set fwd csum' to switch forwarding engine.
> >
> > 2. By default, csum forwarding engine compulsorily changes ethernet
> > addresses. So please make sure that MAC addresses are correct.
> >
> > 3. When enable GRO for port0, csum forwarding engine will merge
> > packets received from port0. If there are no packets from port1 to
> > port0, you don't need to enable GRO for port1.
> >
> > 4. GRO library doesn't re-calculate checksums for merged packets. If
> > you want merged packets have correct checksum, please select HW IP and
> > HW TCP checksum calculation for the port which the merged packets are
> > transmitted to in csum forwarding engine.
> > This is because the merged packets are multi-segment mbufs, but csum
> > forwarding engine doesn't support to calculate checksums for
> > multi-segment mbufs in SW. So we need to select HW checksum offloading.
> >
> > e.g. If data flow is "packets -> port0 -> port1", commands used in testpmd:
> > 	gro on port0
> > 	set fwd csum
> > 	csum set ip hw port1
> > 	csum set tcp hw port1
> >
> >
> > Besides, you need to make sure that your PMD driver doesn't use vector
> > TX function, since vector function doesn't support checksum offloading.
> >
> > >
> > > “””
> > >
> > >
> > >
> > > And trying to send TCP_IPV4 fragmented packet “packet with length
> > > 1500 fragmented to three packets of 500”
> > >
> > > “””
> > >
> > > p=Ether(src=get_if_hwaddr('ens10'), dst=
> > > '24:8A:07:88:26:6B')/IP()/TCP()
> > >
> > > p.add_payload('F'*(1500 - len(p)))
> > >
> > > frags=fragment(p,fragsize=500)
> > >
> > > for fragment in frags:
> > >
> > >      sendp(fragment, iface='ens10')
> > >
> > > “””
> > >
> > >
> > >
> > > But the testpmd forward the packets as it is, “ doesn’t do any merge”
> > >
> > >
> > >
> > > Tcpdump at the TG side,
> > >
> > > The sending fragmets using ens10:
> > >
> > > #tcpdump –I ens10 –vvven
> > >
> > > 15:45:29.083514 24:8a:07:88:26:5b > 24:8a:07:88:26:6b, ethertype
> > > IPv4 (0x0800), length 538: (tos 0x0, ttl 64, id 1, offset 0, flags
> > > [+], proto Options (0), length 524)
> > >
> > >     127.0.0.1 > 127.0.0.1:  ip-proto-0 504
> > >
> > > 15:45:29.115266 24:8a:07:88:26:5b > 24:8a:07:88:26:6b, ethertype
> > > IPv4 (0x0800), length 538: (tos 0x0, ttl 64, id 1, offset 504, flags
> > > [+], proto Options (0), length 524)
> > >
> > >     127.0.0.1 > 127.0.0.1: ip-proto-0
> > >
> > > 15:45:29.147258 24:8a:07:88:26:5b > 24:8a:07:88:26:6b, ethertype
> > > IPv4 (0x0800), length 492: (tos 0x0, ttl 64, id 1, offset 1008,
> > > flags [none], proto Options (0), length 478)
> > >
> > >     127.0.0.1 > 127.0.0.1: ip-proto-0
> > >
> > >
> > >
> > > #tcpdump -i ens9 –vvven  /// here will be received the forwarded
> > > packets from
> > > testpmd:
> > >
> > > 15:45:29.083996 24:8a:07:88:26:5b > 24:8a:07:88:26:6b, ethertype
> > > IPv4 (0x0800), length 538: (tos 0x0, ttl 64, id 1, offset 0, flags
> > > [+], proto Options (0), length 524)
> > >
> > >     127.0.0.1 > 127.0.0.1:  ip-proto-0 504
> > >
> > > 15:45:29.115425 24:8a:07:88:26:5b > 24:8a:07:88:26:6b, ethertype
> > > IPv4 (0x0800), length 538: (tos 0x0, ttl 64, id 1, offset 504, flags
> > > [+], proto Options (0), length 524)
> > >
> > >     127.0.0.1 > 127.0.0.1: ip-proto-0
> > >
> > > 15:45:29.147492 24:8a:07:88:26:5b > 24:8a:07:88:26:6b, ethertype
> > > IPv4 (0x0800), length 492: (tos 0x0, ttl 64, id 1, offset 1008,
> > > flags [none], proto Options (0), length 478)
> > >
> > >     127.0.0.1 > 127.0.0.1: ip-proto-0
> > >
> > >
> > >
> > >
> > >
> > > Am I doing something wrong?! Or it is a bug.
> > >
> > > è As you see the tcpdump shows the offset of each fragment, and
> > > testpmd prints L4_FRAG, so the both are recognizing that this is a
> > fragmented packet.
> >
> > GRO library merges TSOed/GSOed packets, whose IP IDs and TCP
> sequences
> > are both consecutive. If input packets have same IP IDs, no packets
> > will be merged.
> >
> > BTW, you can use iperf to test GRO feature.
> >
> > Best Regards,
> > Jiayu
> >
> > >
> > >
> > >
> > > Best regards,
> > >
> > > Wisam Jaddo
> > >
> > >
> > >