On Mon, Jan 16, 2017 at 12:01 PM, Ben Pfaff <b...@ovn.org> wrote: > On Mon, Jan 16, 2017 at 09:28:28AM -0500, Russell Bryant wrote: > > On Sat, Jan 14, 2017 at 11:29 AM, Ben Pfaff <b...@ovn.org> wrote: > > > > > On Sat, Jan 14, 2017 at 07:37:53PM +0530, Numan Siddique wrote: > > > > On Sat, Jan 14, 2017 at 3:18 AM, Ben Pfaff <b...@ovn.org> wrote: > > > > > > > > > On Tue, Jan 10, 2017 at 11:34:42AM +0530, Numan Siddique wrote: > > > > > > ovn-controller by default enables UDP checksums for geneve > > > > > > tunnels. With this patch user can set the desired value in > > > > > > Open_vSwitch.external_ids:ovn_encap_csum. > > > > > > > > > > > > Signed-off-by: Numan Siddique <nusid...@redhat.com> > > > > > > > > > > I don't see technical problems with this, but I also don't know > why a > > > > > user would want to disable checksums. Can you send a v2 that adds > this > > > > > rationale to the documentation and to the commit message? > > > > > > > > > > > > > Thanks for the review. Sure I will do that. The reason for this > patch is > > > - > > > > we are seeing significant performance increase (more than 100%) in > our > > > > testing when tunnel checksum is disabled. > > > > > > > > The lab servers have nics with geneve offload support ( > > > > tx-udp_tnl-segmentation > > > > ) > > > > . > > > > > > OK, that sounds like a good reason to document. > > > > > > In particular, it looks like the NICs we have, Intel X710, will do TCP > > Segmentation Offload (TSO) with geneve or vxlan, but only if udp > checksums > > are turned off. Once they're on, TCP throughput gets cut to less than > half. > > > > This is going to be painful to document well if it's hardware dependent. > > I'm not sure what the better default is, since checksums should actually > > improve performance for NICs without geneve offload support. > > Well, it's at least helpful to document that performance is the reason, > and that offloads factor into the issue. Otherwise readers will have no > idea why they'd want to turn off checksums. At worst, users can > benchmark both cases in their environments. >
Totally agreed. I was just adding some more detail about what we've seen, and then reflecting on how we might want to document this new option for users. -- Russell Bryant _______________________________________________ dev mailing list d...@openvswitch.org https://mail.openvswitch.org/mailman/listinfo/ovs-dev