Sorry, I'm really new to network area. So, you mean I should keep the sender under the low MTU, while the receiver with higher MTU size ??
But, how I can make sure the sender is always the sender ???? Thanks. -chen -----Original Message----- From: Jesse Gross [mailto:[email protected]] Sent: Tuesday, January 07, 2014 11:20 AM To: Li, Chen Cc: [email protected] Subject: Re: [ovs-discuss] low bandwidth for gre If you change the MTU of both interfaces then it will still result in fragmentation. On Mon, Jan 6, 2014 at 9:50 PM, Li, Chen <[email protected]> wrote: > Yes, fragmentation do affect the bandwidth. > > I run command to change interfaces' MTU size to test if fragmentation makes > a difference. > ifconfig eth4 mtu ${mtu_size} > ifconfig br-int mtu ${mtu_size} > > The default MTU = 1500 => 122 Kbits/sec > MTU = 3000 => 419 Kbits/sec > MTU = 6000 => 780 Kbits/sec > MTU = 9000 => 1.14 Mbits/sec > > > But, what I don’t understand is, I didn’t see really high CPU%. > > Also, there is no other way to improve the bandwidth ? > Even under MTU=9000, 1.14 Mb/s vs. 10 Gb/s, the gap between the test result > we can get and the physical NIC is unacceptable!! > > > Thanks. > -chen > > > -----Original Message----- > From: Jesse Gross [mailto:[email protected]] > Sent: Tuesday, January 07, 2014 10:32 AM > To: Li, Chen > Cc: [email protected] > Subject: Re: [ovs-discuss] low bandwidth for gre > > Well did you at least see if fragmentation makes a difference? > > On Mon, Jan 6, 2014 at 8:14 PM, Li, Chen <[email protected]> wrote: >> But 122 Kbits/s vs. 9.41Gb/s ?? >> >> Is this correct ??? >> >> How can I improve it ?? >> >> >> Thanks. >> -chen >> >> >> -----Original Message----- >> From: Jesse Gross [mailto:[email protected]] >> Sent: Tuesday, January 07, 2014 12:24 AM >> To: Li, Chen >> Cc: [email protected] >> Subject: Re: [ovs-discuss] low bandwidth for gre >> >> On Sun, Jan 5, 2014 at 11:58 PM, Li, Chen <[email protected]> wrote: >>> Hi list, >>> >>> >>> >>> I’m working under CentOS, so the kernel is >>> 2.6.32-358.123.2.openstack.el6.x86_64. >>> >>> openvswitch.x86_64 1.11.0_8ce28d-1.el6ost >>> >>> >>> >>> I have two physical machine in the test, each of them have a 10 Gb NIC card. >>> >>> The bandwidth between the two machine using iperf can achieve 9.41Gb/s. >>> >>> >>> >>> After enable gre follow guide >>> http://networkstatic.net/configuring-vxlan-and-gre-tunnels-on-openvs >>> w >>> i >>> tch/#!prettyPhoto >>> >>> The bandwitdth between the two nodes are really low. >>> >>> Only 122 Kbits/s !!!! >> >> At a minimum, fragmentation is presumably occurring. _______________________________________________ discuss mailing list [email protected] http://openvswitch.org/mailman/listinfo/discuss
