Hi,
Trying AF_XDP xdpsock txonly on an i40e (XL710), I'm seeing some
behaviour across packet size that I need help to understand.
All tests with zero-copy mode (similar results with busy poll mode
also). The i40e driver version is the native kernel version 6.8.0-47
included in Ubuntu 24.04. Flow control tx/rx is off.
PktSize Max-pps Actual-pps
64
59.5M ~18.9M
512
9.4M ~7.5M
1024
4.8M ~4.6M
1518
3.3M ~3.0M
Output logs below
Since 64 byte packets can do around ~18.9M, I was expecting larger
packets (see 512 and 1518 above) to do line rate i.e. do close to
max-pps but they do less than that.
Is this expected?
What factors could be playing a role in a lower rate for larger packet size?
To determine how many cores/queues I need if I need to transmit X Gbps
- what factors do I need to use?
Srivats
$ sudo ./xdpsock -t -i enp1s0f0np0 -z -d5 -s64
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 1,88,28,546 1,88,39,104
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 1,88,25,658 3,76,73,792
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 1,92,29,105 5,69,07,520
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 1,96,44,299 7,65,55,904
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 1,96,46,711 9,62,06,336
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 0.00
rx 0 0
tx 0 9,62,06,720
$ sudo ./xdpsock -t -i enp1s0f0np0 -z -d5 -s512
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 75,09,247 75,11,104
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 74,89,511 1,50,01,856
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 74,98,753 2,25,01,568
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 74,86,126 2,99,88,672
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 74,86,807 3,74,76,416
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 0.00
rx 0 0
tx 0 3,74,76,416
$ sudo ./xdpsock -t -i enp1s0f0np0 -z -d5 -s1024
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 46,01,574 46,02,496
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 45,95,655 91,98,912
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 45,95,058 1,37,94,432
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 45,97,400 1,83,92,256
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 45,84,541 2,29,77,152
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 0.00
rx 0 0
tx 0 2,29,77,216
$ sudo ./xdpsock -t -i enp1s0f0np0 -z -d5 -s1518
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 30,00,232 30,00,960
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 29,94,793 59,96,224
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 29,95,064 89,91,616
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 29,96,147 1,19,88,160
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 1.00
rx 0 0
tx 29,94,991 1,49,83,552
sock0@enp1s0f0np0:0 txonly xdp-drv
pps pkts 0.00
rx 0 0
tx 0 1,49,83,552
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