SYMC: Incosistent vrouter throughput

[Rudrajit Tapadar]

While using web-polygraph for performance testing a web server vm, we noticed that the throughput varies a lot with every run. In a comparable system with AWS and baremetal servers the throughput is consistent.

This can also be reproduced by running iperf for smaller windows sizes (20k).

[ajeet vijayvergiya (ajeet17181)]

Following iperf tests performed with below topology
Opencontrail version 2.22 (Ubuntu trusty build) all in one setup created with two VM attached to vrouter
The variance of bandwidth across trials is not huge.
Detailed results below

Test case 1
iperf with default settings (Window Size 45K, Jumbo Packets)

iperf result for 15 runs (Min 7.05 Gbits/s, Max 8.66 Gbits/s)
Duration Total Data Throughput
0.0-10.0 sec 9.51 GBytes 8.17 Gbits/sec
0.0-10.0 sec 9.98 GBytes 8.57 Gbits/sec
0.0-10.0 sec 10.1 GBytes 8.66 Gbits/sec
0.0-10.0 sec 9.10 GBytes 7.82 Gbits/sec
0.0-10.0 sec 8.85 GBytes 7.60 Gbits/sec
0.0-10.0 sec 8.78 GBytes 7.54 Gbits/sec
0.0-10.0 sec 9.72 GBytes 8.35 Gbits/sec
0.0-10.0 sec 8.79 GBytes 7.55 Gbits/sec
0.0-10.0 sec 8.98 GBytes 7.71 Gbits/sec
0.0-10.0 sec 8.21 GBytes 7.05 Gbits/sec
0.0-10.0 sec 9.23 GBytes 7.93 Gbits/sec
0.0-10.0 sec 8.50 GBytes 7.30 Gbits/sec
0.0-10.0 sec 8.80 GBytes 7.56 Gbits/sec
0.0-10.0 sec 8.29 GBytes 7.12 Gbits/sec
0.0-10.0 sec 8.76 GBytes 7.52 Gbits/sec

Test case 2
iperf with window size set as 20K and Jumbo Packets
iperf result for 15 runs (Min 249 Mbits/s, Max 394 Mbits/s)

Duration Total Data Throughput
0.0-10.0 sec 313 MBytes 263 Mbits/sec
0.0-10.0 sec 297 MBytes 249 Mbits/sec
0.0-10.0 sec 470 MBytes 394 Mbits/sec
0.0-10.0 sec 313 MBytes 262 Mbits/sec
0.0-10.0 sec 461 MBytes 387 Mbits/sec
0.0-10.0 sec 400 MBytes 336 Mbits/sec
0.0-10.0 sec 316 MBytes 265 Mbits/sec
0.0-10.0 sec 314 MBytes 263 Mbits/sec
0.0-10.0 sec 306 MBytes 256 Mbits/sec
0.0-10.0 sec 309 MBytes 259 Mbits/sec
0.0-10.0 sec 318 MBytes 266 Mbits/sec
0.0-10.0 sec 462 MBytes 387 Mbits/sec
0.0-10.0 sec 305 MBytes 256 Mbits/sec
0.0-10.0 sec 369 MBytes 309 Mbits/sec
0.0-10.0 sec 433 MBytes 363 Mbits/sec

Test case 3
iperf with window size 45K and packet length set to 1000
iperf result for 15 runs (Min 327 Mbits/s, Max 427 Mbits/s)

Duration Total Data Throughput
0.0-10.0 sec 447 MBytes 375 Mbits/sec
0.0-10.0 sec 509 MBytes 427 Mbits/sec
0.0-10.0 sec 438 MBytes 368 Mbits/sec
0.0-10.0 sec 490 MBytes 411 Mbits/sec
0.0-10.0 sec 458 MBytes 384 Mbits/sec
0.0-10.0 sec 435 MBytes 365 Mbits/sec
0.0-10.0 sec 466 MBytes 391 Mbits/sec
0.0-10.0 sec 410 MBytes 344 Mbits/sec
0.0-10.0 sec 498 MBytes 418 Mbits/sec
0.0-10.0 sec 434 MBytes 364 Mbits/sec
0.0-10.0 sec 390 MBytes 327 Mbits/sec
0.0-10.0 sec 441 MBytes 370 Mbits/sec
0.0-10.0 sec 456 MBytes 383 Mbits/sec
0.0-10.0 sec 507 MBytes 426 Mbits/sec
0.0-10.0 sec 468 MBytes 392 Mbits/sec