On Thu, May 5, 2016 at 1:26 AM, Chandran, Sugesh <sugesh.chand...@intel.com> wrote: >> -----Original Message----- >> From: Jesse Gross [mailto:je...@kernel.org] >> Sent: Wednesday, May 4, 2016 10:06 PM >> To: Chandran, Sugesh <sugesh.chand...@intel.com> >> Cc: pravin shelar <pshe...@ovn.org>; ovs dev <dev@openvswitch.org> >> Subject: Re: [ovs-dev] [PATCH v2] tunneling: Improving tunneling >> performance using DPDK Rx checksum offloading feature. >> >> On Wed, May 4, 2016 at 8:58 AM, Chandran, Sugesh >> <sugesh.chand...@intel.com> wrote: >> >> -----Original Message----- >> >> From: Jesse Gross [mailto:je...@kernel.org] >> >> Sent: Thursday, April 28, 2016 4:41 PM >> >> To: Chandran, Sugesh <sugesh.chand...@intel.com> >> >> Cc: pravin shelar <pshe...@ovn.org>; ovs dev <dev@openvswitch.org> >> >> Subject: Re: [ovs-dev] [PATCH v2] tunneling: Improving tunneling >> >> performance using DPDK Rx checksum offloading feature. >> > >> >> That sounds great, thanks for following up. In the meantime, do you >> >> have any plans for transmit side checksum offloading? >> > [Sugesh] The vectorization on Tx side is getting disabled when DPDK Tx >> checksum offload is enabled. This causes performance drop in OVS. >> > However We don’t find any such impact when enabling Rx checksum >> offloading(though this disables Rx vectorization). >> >> OK, I see. Does the drop in throughput cause performance to go below the >> baseline even for UDP tunnels with checksum traffic? (I guess small and large >> packets might have different results here.) Or is it that it reduce >> performance >> for unrelated traffic? If it's the latter case, can we find a way to use >> offloading >> conditionally? > [Sugesh] We tested for 64 byte UDP packet stream and found that the > performance > is better when the offloading is turned off. This is for any traffic through > the port. > DPDK doesn’t support conditional offloading for now. > In other words DPDK can't do selective vector packet processing on a port. > As far as I know there are some technical difficulties to enable offload + > vectorization together > in DPDK.
My guess is the results might be different for larger packets since those cases will stress checksumming more and rx/tx routines less. In any case, I think this is an area that is worthwhile to continue investigating. My expectation is that tunneled packets with outer UDP checksums will be a use case that is hit increasingly frequently with OVS DPDK - for example, OVN will likely start exercising this soon. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev