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

["Zhou, Tianlin" <tianlin.zhou@tekcomms.com>]

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