Re: [dpdk-dev] Poor Virtio PMD TX Performance

["Ouyang, Changchun" <changchun.ouyang@intel.com>]

Hi Tianlin

Thanks very much for your inputs,
I will investigate this issue and update to you after I have any findings.

Changchun

> -----Original Message-----
> From: Zhou, Tianlin [mailto:tianlin.zhou@tekcomms.com]
> Sent: Friday, June 12, 2015 5:36 PM
> To: dev@dpdk.org; Ouyang, Changchun
> Subject: RE: Poor Virtio PMD TX Performance
> 
> Hi Changchun,
> 
> Thanks for your response.
> Please see my embedded comments.
> 
> What kind of vhost in your test? Linux vhost or dpdk user space vhost?
> [tzhou] We use Linux vhost.
> 
> Do you enable the dump/log in your test? It will decrease perf of vritio.
> [tzhou] No, I did not enable dump/log in the performance testing.
> I just opened log to debug why drop packets and then close it for higher
> performance.
> 
> 
> Which version of dpdk codes are you using? The tip codes in dpdk.org?
> [tzhou] I used DPDK 2.0.0 and l2fwd in DPDK 2.0.0.
> l2fwd start command: ./l2fwd -c 0x2 -n 1 --p 0x1
> 
> qemu start command (I used the virtio interface for RX/TX in GUEST):
> sudo kvm -m 4096M -smp 4 -hda /home/geo/yanghe/fedora20.qcow2  -boot
> d -daemonize -monitor \ telnet::10024,server,nowait,nodelay \ -cpu host \ -
> device e1000,netdev=public0,mac=00:0c:29:e1:f3:ff -netdev
> user,id=public0,hostfwd=tcp::11022-:22 \ -device virtio-net-
> pci,netdev=public1,mac=00:0c:29:e1:ff:ff,ioeventfd=on -netdev
> tap,id=public1,ifname=tapvm02,script=/home/geo/tzhou/kvm-
> image/tup.sh,downscript=no,vhost=on
> 
> The qemu version?
> [tzhou]
> root@dw-2:/home/geo/tzhou/kvm-image# kvm -version QEMU emulator
> version 2.0.0 (Debian 2.0.0+dfsg-2ubuntu1.3), Copyright (c) 2003-2008 Fabrice
> Bellard
> 
> -Tianlin
> 
> -----Original Message-----
> From: Ouyang, Changchun [mailto:changchun.ouyang@intel.com]
> Sent: Monday, June 08, 2015 10:13 AM
> To: Zhou, Tianlin
> Cc: Ouyang, Changchun
> Subject: RE: Poor Virtio PMD TX Performance
> 
> Hi tianlin,
> 
> What kind of vhost in your test? Linux vhost or dpdk user space vhost?
> 
> Do you enable the dump/log in your test? It will decrease perf of vritio.
> 
> Which version of dpdk codes are you using? The tip codes in dpdk.org?
> 
> The qemu version?
> 
> Thanks for inputs
> Changchun
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Zhou, Tianlin
> > Sent: Friday, June 5, 2015 5:23 PM
> > To: dev@dpdk.org
> > Subject: [dpdk-dev] Poor Virtio PMD TX Performance
> >
> > Hi there,
> >
> > We tested TX performance of Virtio PMD by DPDK l2fwd, but found even
> > at 60KPPS (720B packet length) TX rate, there is 1/1000 packet dropping
> rate.
> > The log shows "No free tx descriptors to transmit" in Virtio PMD.
> > Increasing TX queues by modifying DPDK l2fwd can decreases packet
> > dropping rate, but can't ensure no packet dropping unless
> > retransmitting packets that can't be sent successfully.
> > Oppositely, RX rate can be 600KPPS without packet dropping.
> >
> > Test Env
> > - Host CPU: 4 cores, 2127.770MHz
> > - Host Memory: 8G
> > - Host OS: Linux dw-2 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10
> > 19:11:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
> > - Guest CPU: 4 cores, 2127.770MHz
> > - Guest Memory: 4G
> > - Guest OS: fedora20
> >
> > Anybody here face the same problem?
> >
> > -Tianlin