On Mon, Jan 16, 2017 at 11:46 PM, Russell Bryant <[email protected]> wrote:
> > > On Mon, Jan 16, 2017 at 12:01 PM, Ben Pfaff <[email protected]> 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 <[email protected]> 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 <[email protected]> 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 <[email protected]> >> > > > > >> > > > > 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. > > I have submitted v2 of the patch with updated documenation - https://mail.openvswitch.org/pipermail/ovs-dev/2017-January/327660.html Thanks Numan > -- > Russell Bryant > _______________________________________________ dev mailing list [email protected] https://mail.openvswitch.org/mailman/listinfo/ovs-dev
