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 at 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.ouy...@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 at dpdk.org] On Behalf Of Zhou, Tianlin > Sent: Friday, June 5, 2015 5:23 PM > To: dev at 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
