[ovs-discuss] Re: [HELP] Question about Performance issues in high concurrency scenarios

txfh2007 txfh2007 at aliyun.com
Fri Mar 15 07:22:31 UTC 2019

Hi Yanqin && all:
    I have studied this ppt && vedio, and  tried in my own environment. The result is in 100K mac-ip PVP test scenario, when EM_FLOW_HASH_SHIFT == 17(emc entry num is 130K+), the performance can still maintain(a little decline than 10K mac-ip scenario). My formal conclusion is wrong as I didn't notice that if I generate 100K mac-ip flows , then the mac-table-entry num in ovs bridge should be enlarge simultaneously(I use the auto learn flow entries)

   I also tested scenario that smc is enabled and emc disabled. My result is pure smc performance is slightly not good as emc.(100K mac-ip flows, pkt size is 64 bytes, 4pmd lcores , 10G nic , PVP test, smc can reach 3.7G throughput, latency is 56us. For emc throughput is 4G , latency 51us )

   My question is: should emc entry num get enlarged ? Are there any drawbacks if emc entry is larger than 100K ?

发件人:Yanqin Wei (Arm Technology China) <Yanqin.Wei at arm.com>
发送时间:2019年3月14日(星期四) 10:05
收件人:txfh2007 <txfh2007 at aliyun.com>; Flavio Leitner <fbl at sysclose.org>
抄 送:ovs-discuss <ovs-discuss at openvswitch.org>
主 题:RE: [ovs-discuss] Re: [HELP] Question about Performance issues in high concurrency scenarios

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There is a interesting topic in Open vSwitch 2018 Fall Conference maybe helpful for you. It shows EMC/SMC behave different performance in high concurrency case.
For your case, SMC may be more helpful.
From: ovs-discuss-bounces at openvswitch.org <ovs-discuss-bounces at openvswitch.org>On Behalf Of txfh2007 via discuss
Sent: Thursday, March 14, 2019 9:00 AM
To: Flavio Leitner <fbl at sysclose.org>
Cc: ovs-discuss <ovs-discuss at openvswitch.org>
Subject: [ovs-discuss] Re: [HELP] Question about Performance issues in high concurrency scenarios

    So there are two questions: 

    1. Is dpcls lookup More efficiency than EMC?

    2. If I just want to enlarge emc entry num by change EM_FLOW_HASH_SHIFT value, are there any drawbacks ?




发件人:Flavio Leitner <fbl at sysclose.org>

发送时间:2019年3月14日(星期四) 04:05

收件人:txfh2007 <txfh2007 at aliyun.com>

抄 送:ovs-discuss <ovs-discuss at openvswitch.org>

主 题:Re: [ovs-discuss] [HELP] Question about Performance issues in high concurrency scenarios


On Tue, Mar 05, 2019 at 03:38:43PM +0800, txfh2007 via discuss wrote:
> Hi everyone:    
>      I have test ovs-dpdk PVP performance for several days . And I
>      have found in high concurrency scenarios(eg. 100K mac-ip
>      streams), the ovs-dpdk performance gets significant decline.
>      And one cause of performance decline is the emc entry num
>      limitation, is that right? If I just increase emc entry num,
>      will other problems occur ? Are there any suggession helping to
>      get performance improvement under high concurrency scenarios?

Perhaps you could consider disabling EMC if its size is not enough.

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