First of all, sorry for taking more time to get back to this series and thanks to all valuble feedback in series-1 at [1] from Jesper and Song Liu. Since then I have looked into what Jesper suggested in [2] and worked on revising the patch series into several patches for ease of review: v1->v2: 1/7: [No change]. Add VLAN tag (ID & Priority) to the generated Tx-Only frames. 2/7: [No change]. Add DMAC and SMAC setting to the generated Tx-Only frames. If parameters are not set, previous DMAC and SMAC are used. 3/7: [New]. Add support for selecting different CLOCK for clock_gettime() used in get_nsecs. 4/7: [New]. This is a total rework from series-1 3/4-patch [3]. It uses clock_nanosleep() suggested by Jesper. In addition, added statistic for Tx schedule variance under application stat (-a|--app-stats). Make the cyclic Tx operation and --poll mode to be mutually- exclusive. Still, the ability to specify TX cycle time and used together with batch size and packet count remain the same. 5/7: [New]. Add the support for TX process schedule policy and priority setting. By default, SCHED_OTHER policy is used. This too is matching the schedule policy setting in [2]. 6/7: [Change]. This is update from series-1 4/4-patch [4]. Added TX clean process time-out in 1s granularity with configurable retries count (-O|--retries). 7/7: [New]. Added timestamp for TX packet following pktgen_hdr format matching the implementation in [2]. However, the sequence ID remains the same as it is instead of process schedule diff in [2]. To summarize on what program options have been added with v2 series using an example below:- DMAC (-G) = fa:8d:f1:e2:0b:e8 SMAC (-H) = ce:17:07:17:3e:3a VLAN tagged (-V) VLAN ID (-J) = 12 VLAN Pri (-K) = 3 Tx Queue (-q) = 3 Cycle Time in us (-T) = 1000 Batch (-b) = 2 Packet Count = 6 Tx schedule policy (-W) = FIFO Tx schedule priority (-U) = 50 Clock selection (-w) = REALTIME Tx timeout retries(-O) = 5 Tx timestamp (-y) Cyclic Tx schedule stat (-a) Note: xdpsock sets UDP dest-port and src-port to 0x1000 as default. Sending Board ============= $ xdpsock -i eth0 -t -N -z -H ce:17:07:17:3e:3a -G fa:8d:f1:e2:0b:e8 \ -V -J 12 -K 3 -q 3 \ -T 1000 -b 2 -C 6 -W FIFO -U 50 -w REALTIME \ -O 5 -y -a sock0@eth0:3 txonly xdp-drv pps pkts 0.00 rx 0 0 tx 0 6 calls/s count rx empty polls 0 0 fill fail polls 0 0 copy tx sendtos 0 0 tx wakeup sendtos 0 5 opt polls 0 0 period min ave max cycle Cyclic TX 1000000 31033 32009 33397 3 Receiving Board =============== $ tcpdump -nei eth0 udp port 0x1000 -vv -Q in -X \ --time-stamp-precision nano tcpdump: listening on eth0, link-type EN10MB (Ethernet), capture size 262144 bytes 03:46:40.520111580 ce:17:07:17:3e:3a > fa:8d:f1:e2:0b:e8, ethertype 802.1Q (0x8100), length 62: vlan 12, p 3, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 44) 10.10.10.16.4096 > 10.10.10.32.4096: [udp sum ok] UDP, length 16 0x0000: 4500 002c 0000 0000 4011 527e 0a0a 0a10 E..,....@.R~.... 0x0010: 0a0a 0a20 1000 1000 0018 e997 be9b e955 ...............U 0x0020: 0000 0000 61cd 2ba1 0006 987c ....a.+....| 03:46:40.520112163 ce:17:07:17:3e:3a > fa:8d:f1:e2:0b:e8, ethertype 802.1Q (0x8100), length 62: vlan 12, p 3, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 44) 10.10.10.16.4096 > 10.10.10.32.4096: [udp sum ok] UDP, length 16 0x0000: 4500 002c 0000 0000 4011 527e 0a0a 0a10 E..,....@.R~.... 0x0010: 0a0a 0a20 1000 1000 0018 e996 be9b e955 ...............U 0x0020: 0000 0001 61cd 2ba1 0006 987c ....a.+....| 03:46:40.521066860 ce:17:07:17:3e:3a > fa:8d:f1:e2:0b:e8, ethertype 802.1Q (0x8100), length 62: vlan 12, p 3, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 44) 10.10.10.16.4096 > 10.10.10.32.4096: [udp sum ok] UDP, length 16 0x0000: 4500 002c 0000 0000 4011 527e 0a0a 0a10 E..,....@.R~.... 0x0010: 0a0a 0a20 1000 1000 0018 e5af be9b e955 ...............U 0x0020: 0000 0002 61cd 2ba1 0006 9c62 ....a.+....b 03:46:40.521067012 ce:17:07:17:3e:3a > fa:8d:f1:e2:0b:e8, ethertype 802.1Q (0x8100), length 62: vlan 12, p 3, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 44) 10.10.10.16.4096 > 10.10.10.32.4096: [udp sum ok] UDP, length 16 0x0000: 4500 002c 0000 0000 4011 527e 0a0a 0a10 E..,....@.R~.... 0x0010: 0a0a 0a20 1000 1000 0018 e5ae be9b e955 ...............U 0x0020: 0000 0003 61cd 2ba1 0006 9c62 ....a.+....b 03:46:40.522061935 ce:17:07:17:3e:3a > fa:8d:f1:e2:0b:e8, ethertype 802.1Q (0x8100), length 62: vlan 12, p 3, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 44) 10.10.10.16.4096 > 10.10.10.32.4096: [udp sum ok] UDP, length 16 0x0000: 4500 002c 0000 0000 4011 527e 0a0a 0a10 E..,....@.R~.... 0x0010: 0a0a 0a20 1000 1000 0018 e1c5 be9b e955 ...............U 0x0020: 0000 0004 61cd 2ba1 0006 a04a ....a.+....J 03:46:40.522062173 ce:17:07:17:3e:3a > fa:8d:f1:e2:0b:e8, ethertype 802.1Q (0x8100), length 62: vlan 12, p 3, ethertype IPv4, (tos 0x0, ttl 64, id 0, offset 0, flags [none], proto UDP (17), length 44) 10.10.10.16.4096 > 10.10.10.32.4096: [udp sum ok] UDP, length 16 0x0000: 4500 002c 0000 0000 4011 527e 0a0a 0a10 E..,....@.R~.... 0x0010: 0a0a 0a20 1000 1000 0018 e1c4 be9b e955 ...............U 0x0020: 0000 0005 61cd 2ba1 0006 a04a ....a.+....J I have tested the above with both tagged and untagged packet format and based on the timestamp in tcpdump found that the timing of the batch cyclic transmission is correct. Appreciate if community can give the patch series v2 a try and point out any gap. Thanks Boon Leong [1] https://patchwork.kernel.org/project/netdevbpf/cover/20211124091821.3916046-1-boon.leong.ong@xxxxxxxxx/ [2] https://github.com/netoptimizer/network-testing/blob/master/src/udp_pacer.c [3] https://patchwork.kernel.org/project/netdevbpf/patch/20211124091821.3916046-4-boon.leong.ong@xxxxxxxxx/ [4] https://patchwork.kernel.org/project/netdevbpf/patch/20211124091821.3916046-5-boon.leong.ong@xxxxxxxxx/ Ong Boon Leong (7): samples/bpf: xdpsock: add VLAN support for Tx-only operation samples/bpf: xdpsock: add Dest and Src MAC setting for Tx-only operation samples/bpf: xdpsock: add clockid selection support samples/bpf: xdpsock: add cyclic TX operation capability samples/bpf: xdpsock: add sched policy and priority support samples/bpf: xdpsock: add time-out for cleaning Tx samples/bpf: xdpsock: add timestamp for Tx-only operation samples/bpf/xdpsock_user.c | 363 ++++++++++++++++++++++++++++++++++--- 1 file changed, 341 insertions(+), 22 deletions(-) -- 2.25.1