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List:       dpdk-users
Subject:    Re: [dpdk-users] Virtio-user exceptional path performance
From:       Eric Tremblay <ertr () kaloom ! com>
Date:       2018-09-24 15:25:20
Message-ID: YQBPR0101MB1538A7FBEA6C3FB12741294EAF170 () YQBPR0101MB1538 ! CANPRD01 ! PROD ! OUTLOOK ! COM
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It does not work even if I do the following:

testpmd> set fwd csum
Set csum packet forwarding mode
testpmd> csum set tcp hw 0
Parse tunnel is off
IP checksum offload is sw
UDP checksum offload is sw
TCP checksum offload is hw
SCTP checksum offload is sw
Outer-Ip checksum offload is sw
testpmd> csum set tcp hw 1
Parse tunnel is off
IP checksum offload is sw
UDP checksum offload is sw
TCP checksum offload is hw
SCTP checksum offload is sw
Outer-Ip checksum offload is sw
testpmd>

I also tried using a NIC but it doesn't work either. Packets sent through the \
virtio-user tap interface arrive on the other server with an incorrect checksum. Is \
the checksum offloading broken for this type of virtual device?

Eric 

-----Original Message-----
From: Tiwei Bie <tiwei.bie@intel.com> 
Sent: September 19, 2018 1:08 AM
To: Eric Tremblay <ertr@kaloom.com>
Cc: users@dpdk.org; zhihong.wang@intel.com; maxime.coquelin@redhat.com
Subject: Re: [dpdk-users] Virtio-user exceptional path performance

On Tue, Sep 18, 2018 at 02:45:24PM +0000, Eric Tremblay wrote:
> Thanks for the reply.
> 
> With the patch, the tap interface is created in the kernel even when specifying the \
> --enable-lro and --enable-rx-cksum options. However, the behaviour is the same as \
> without these options. That is, ethtool shows LRO and rx-checksum as off (and \
> [fixed]) and TCP traffic gets dropped unless tx-checksum is turned off. The \
> difference is that testpmd now says that LRO and RX checksum are on (even though \
> they don't seem to be).

Are you using csum fwd in testpmd? You also need to enable the hw csum offload. You \
can do it via:

testpmd> csum set tcp hw 0
testpmd> csum set tcp hw 1

And make sure you get below output:

TCP checksum offload is hw

> 
> Eric
> 
> -----Original Message-----
> From: Tiwei Bie <tiwei.bie@intel.com>
> Sent: September 18, 2018 1:30 AM
> To: Eric Tremblay <ertr@kaloom.com>; users@dpdk.org
> Cc: zhihong.wang@intel.com; maxime.coquelin@redhat.com
> Subject: Re: [dpdk-users] Virtio-user exceptional path performance
> 
> On Tue, Sep 04, 2018 at 05:54:20PM +0000, Eric Tremblay wrote:
> > Hello,
> > 
> > I am testing the performance capabilities of the virtio-user exceptional path for \
> > use in container networking scenarios. I am trying to reproduce the results \
> > obtained in Test Case 1 described in the paper "VIRTIO-USER: A New Versatile \
> > Channel for Kernel-Bypass Networks".  That is, I am creating two virtio-user \
> > vdevs in testpmd, putting each one in separate network namespaces and running \
> > iperf3 between the two. However, I am unable to obtain the near 25Gbps throughput \
> > shown in the paper. Instead, I obtained a mere 3Gbps. Has anyone else been able \
> > to reproduce these results? My understanding is that this type of virtual device \
> > takes advantage of both checksum offloading and LRO in order to get such high \
> > throughput. However, for some reason, I am unable to use RX checksum offloading \
> > nor LRO in my setup. If I specify the --enable-lro and --enable-rx-cksum options \
> > in testpmd (as shown here \
> > https://doc.dpdk.org/guides-17.11/howto/virtio_user_as_exceptional_path.html), \
> > the tap device is never created in the kernel. If I do not specify these options, \
> > the tap is created correctly but the rx-checksum and LRO are off and cannot be \
> > turned on using ethtool (they are marked as [fixed]).
> 
> Somehow below fix isn't backported to 17.11 while the commit it fixed was \
> backported. 
> https://git.dpdk.org/dpdk/commit/?id=bce7e9050f9b
> commit bce7e9050f9b ("net/virtio-user: fix start with kernel vhost")
> 
> Please apply above fix locally and see if it works.
> 
> Thanks
> 
> > 
> > Does anyone have any idea what may be preventing me from taking advantage of \
> > checksum offloading and LRO? Also, I am I right in assuming that this is the \
> > reason why the performance is so poor or could there be another problem with my \
> > setup? I am using DPDK 17.11 on CentOS 7.5. Any help would be appreciated. 
> > Regards,
> > 
> > Eric
> > 


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