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List:       openvswitch-discuss
Subject:    [ovs-discuss] ovs add-port takes long time
From:       ychen103103 () 163 ! com (ychen)
Date:       2014-08-21 2:18:55
Message-ID: 6a3307ed.351b.147f65c1411.Coremail.ychen103103 () 163 ! com
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hi,
Thank you for your reply. I have do some expriment following your adivce.
It seems that add 8 or 50 ports a time may reach the high performance, the \
performance will reduce if we add more than 50 ports a time. (expriment result: total \
4000 ports, 4 ports a time, takes 977 seconds, and 8 ports a time, takes 622 seconds, \
50 ports a time, takes 373 seconds, and 100 ports a time, takes 400 seconds)
If I add 16K ports, then reload the vswitchd and ovsdb, it only takes about 10+ \
minutes. So I think it is adding port to database takes the most time, and it has \
become the bottle neck. Here is the question:
1. why in function ovsdb_idl_txn_commit() need the operation wait?
2. do you have any documents about ovsdb mechanism?









At 2014-08-09 02:53:16, "Gurucharan Shetty" <shettyg at nicira.com> wrote:
> On Wed, Aug 6, 2014 at 11:41 PM, ychen <ychen103103 at 163.com> wrote:
> > hi:
> > i have encountered a problem that ovs add-port takes long time, can you
> > help me?
> > testing enviroment:
> > CentOS release 6.5 (Final),
> > Linux l3vpn2 3.16.0-rc1 #1 SMP Mon Jun 16 15:45:19 EDT 2014 x86_64 x86_64
> > x86_64 GNU/Linux
> > ovs-vswitchd (Open vSwitch) 1.11.0
> > Compiled Jul 30 2013 18:14:54
> > OpenFlow versions 0x1:0x1
> > 
> > testing step:
> > 1. add br0
> > 2. use cmd ovs-vsctl add-port, to add 16K internal ports, each 4 ports are
> > in the same namespace
> > 
> > problem:
> > for the first 100~200 ports, system responds quickly; and then it become
> > slower and slower
> It is sort of expected and the current behavior. You can speed things
> a bit by adding multiple ports with a single ovs-vsctl command
> invocation. 50-100 at a time may help.
> > after the total port numbers reached to 8000, it takes about 3 minutes to
> > add one vport
> > 
> Frankly, anything beyond 5000 ports, you are stressing your system.
> ovs-vswitchd has to manage all those ports, so it will be slow. (I
> have heard people using 10,000 tunnels (not regular ports) and
> apparently that is alright.)
> 
> 
> > analysis:
> > i have read the kernel code, and i don't think it is the reason why ovs
> > add-port  so slowly
> > i doubt whether the ovsdb is the main reason? and how can i fix the problem?
> I don't think it is a simple problem to solve. There are many facets
> to it. You will have to go through the code of both ovsdb-server and
> ovs-vswitchd.
> 
> 
> 
> > 
> > 
> > 
> > 
> > _______________________________________________
> > discuss mailing list
> > discuss at openvswitch.org
> > http://openvswitch.org/mailman/listinfo/discuss
> > 
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