All, The receive checksum issue seems to be caused by using a RX_FREE_THRESH value that is 32 or larger, as validated by the test-pmd application. I used 2 different packet types - bad IP checksum sent to port 0 and bad tcp checksum to port 1. The way I was sending the packets did not vary between the various tests.
Below is a brief summary of the testing - additional gory text is attached. 0, 8, 16, 24, 28, 30, 31 are okay. Values above 32 are not, as tested with 32, 64 and 128. I will continue researching this - The version I used to test this is the vanilla version of DPDK 1.3, but with the RSC disable patch applied (helps when there are many ACKs). Thanks, Bryan Benson [bmbenson]~/1.3.1.1/DPDK% sudo ./x86_64-default-linuxapp-gcc/app/testpmd -c 0xFF00FF00 -n 4 -b 0000:06:00.0 -- --portmask=0x3 --nb-cores=2 --enable-rx-cksum --disable-hw-vlan --disable-rss --crc-strip --rxd=1024 --txd=1024 -i ... <text removed> testpmd> set fwd csum Set csum packet forwarding mode testpmd> start csum packet forwarding - CRC stripping enabled - packets/burst=16 nb forwarding cores=2 - nb forwarding ports=2 RX queues=1 - RX desc=1024 - RX free threshold=0 RX threshold registers: pthresh=8 hthresh=8 wthresh=4 TX queues=1 - TX desc=1024 - TX free threshold=0 TX threshold registers: pthresh=36 hthresh=0 wthresh=0 TX RS bit threshold=0 - TXQ flags=0x0 testpmd> stop Telling cores to stop... Waiting for lcores to finish... ---------------------- Forward statistics for port 0 ---------------------- RX-packets: 490511 RX-dropped: 0 RX-total: 490511 Bad-ipcsum: 490496 Bad-l4csum: 0 TX-packets: 488720 TX-dropped: 0 TX-total: 488720 ---------------------------------------------------------------------------- ---------------------- Forward statistics for port 1 ---------------------- RX-packets: 488804 RX-dropped: 0 RX-total: 488804 Bad-ipcsum: 0 Bad-l4csum: 488704 TX-packets: 490511 TX-dropped: 0 TX-total: 490511 ---------------------------------------------------------------------------- +++++++++++++++ Accumulated forward statistics for all ports+++++++++++++++ RX-packets: 979315 RX-dropped: 0 RX-total: 979315 TX-packets: 979231 TX-dropped: 0 TX-total: 979231 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Done. [bmbenson]~/1.3.1.1/DPDK% sudo ./x86_64-default-linuxapp-gcc/app/testpmd -c 0xFF00FF00 -n 4 -b 0000:06:00.0 -- --portmask=0x3 --nb-cores=2 --enable-rx-cksum --disable-hw-vlan --disable-rss --crc-strip --rxd=1024 --txd=1024 --rxfreet=32 -i ... <text removed> testpmd> set fwd csum Set csum packet forwarding mode testpmd> start csum packet forwarding - CRC stripping enabled - packets/burst=16 nb forwarding cores=2 - nb forwarding ports=2 RX queues=1 - RX desc=1024 - RX free threshold=32 RX threshold registers: pthresh=8 hthresh=8 wthresh=4 TX queues=1 - TX desc=1024 - TX free threshold=0 TX threshold registers: pthresh=36 hthresh=0 wthresh=0 TX RS bit threshold=0 - TXQ flags=0x0 testpmd> stop Telling cores to stop... Waiting for lcores to finish... ---------------------- Forward statistics for port 0 ---------------------- RX-packets: 378894 RX-dropped: 0 RX-total: 378894 Bad-ipcsum: 0 Bad-l4csum: 0 TX-packets: 381197 TX-dropped: 0 TX-total: 381197 ---------------------------------------------------------------------------- ---------------------- Forward statistics for port 1 ---------------------- RX-packets: 381197 RX-dropped: 0 RX-total: 381197 Bad-ipcsum: 0 Bad-l4csum: 0 TX-packets: 378894 TX-dropped: 0 TX-total: 378894 ---------------------------------------------------------------------------- +++++++++++++++ Accumulated forward statistics for all ports+++++++++++++++ RX-packets: 760091 RX-dropped: 0 RX-total: 760091 TX-packets: 760091 TX-dropped: 0 TX-total: 760091 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
