Hello, If you prefer to not play with MTU settings every time, I`d recommend to recompile this kernel setting all GRE options as a module and build openvswitch module from vendor package, it will work perfectly with 1.9+ at least.
On 01/07/2014 09:51 AM, Li, Chen wrote: > eth4 MTU = 1500, and br-int MTU = 1200 => 2.76 Gbits/sec > > Also, I tested in Openstack environment, while all virtual ports MTU are > 1500, and eth4 MTU = 9000 > The bandwidth between 2 instances is about 2Gb/s. > > Thanks. > -chen > > > -----Original Message----- > From: Zhou, Han [mailto:hzh...@ebay.com] > Sent: Tuesday, January 07, 2014 1:46 PM > To: Li, Chen; Chris Luke; 'Jesse Gross' > Cc: discuss@openvswitch.org > Subject: RE: [ovs-discuss] low bandwidth for gre > > Hi Chen, > > Are you sure it is only MTU change resulted in such a huge difference? > It is hard to believe that fragmentation itself would lead to 9G -> 122K > performance degradation. > Could you try eth4 MTU = 1500, and br-int MTU = 1200? > > Best regards, > Han > > -----Original Message----- > From: discuss-boun...@openvswitch.org > [mailto:discuss-boun...@openvswitch.org] On Behalf Of Li, Chen > Sent: Tuesday, January 07, 2014 12:46 PM > To: Chris Luke; 'Jesse Gross' > Cc: discuss@openvswitch.org > Subject: Re: [ovs-discuss] low bandwidth for gre > > O. > Thanks for the reply. > I just tried... And it works great !! > I can achieve 9.84 Gbits/sec now while br-int has MTU 8000, while eth4 has > MTU 9000. > > Thanks a lot for the help ! > > -chen > > -----Original Message----- > From: Chris Luke [mailto:chr...@flirble.org] > Sent: Tuesday, January 07, 2014 11:46 AM > To: Li, Chen; 'Jesse Gross' > Cc: discuss@openvswitch.org > Subject: RE: [ovs-discuss] low bandwidth for gre > > No, he means the physical interface needs a larger MTU than the logical one. > The physical one has to transport the packets your logical interface accepts > plus the header data for GRE. If there isn't enough headroom then it must > split the packet in two and reassemble at the far end - a slow process. > > Chris. > > > > >> -----Original Message----- >> From: discuss-boun...@openvswitch.org [mailto:discuss- >> boun...@openvswitch.org] On Behalf Of Li, Chen >> Sent: Monday, January 06, 2014 22:23 >> To: Jesse Gross >> Cc: discuss@openvswitch.org >> Subject: Re: [ovs-discuss] low bandwidth for gre >> >> 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:je...@nicira.com] >> Sent: Tuesday, January 07, 2014 11:20 AM >> To: Li, Chen >> Cc: discuss@openvswitch.org >> 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 <chen...@intel.com> 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:je...@nicira.com] >>> Sent: Tuesday, January 07, 2014 10:32 AM >>> To: Li, Chen >>> Cc: discuss@openvswitch.org >>> 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 <chen...@intel.com> 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:je...@nicira.com] >>>> Sent: Tuesday, January 07, 2014 12:24 AM >>>> To: Li, Chen >>>> Cc: discuss@openvswitch.org >>>> Subject: Re: [ovs-discuss] low bandwidth for gre >>>> >>>> On Sun, Jan 5, 2014 at 11:58 PM, Li, Chen <chen...@intel.com> 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-open >>>>> vs >>>>> 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 >> discuss@openvswitch.org >> http://openvswitch.org/mailman/listinfo/discuss > > _______________________________________________ > discuss mailing list > discuss@openvswitch.org > http://openvswitch.org/mailman/listinfo/discuss > _______________________________________________ > discuss mailing list > discuss@openvswitch.org > http://openvswitch.org/mailman/listinfo/discuss > _______________________________________________ discuss mailing list discuss@openvswitch.org http://openvswitch.org/mailman/listinfo/discuss
