Performance issue with Rancher

[maxisam]

Is this a BUG REPORT?

I used default Rancher 2.5.7 setting for weave with 1376 MTU

My network is 10GBit/s

What you expected to happen?

Pod to Pod should at least get 80% speed.

What happened?

=========================================================
 Benchmark Results
=========================================================
 Name            : knb-68458
 Date            : 2021-04-29 17:21:42 UTC
 Generator       : knb
 Version         : 1.5.0
 Server          : ck8sdl03
 Client          : ck8sdl02
 UDP Socket size : auto
=========================================================
  Discovered CPU         : Intel(R) Xeon(R) Gold 6150 CPU @ 2.70GHz
  Discovered Kernel      : 5.4.0-65-generic
  Discovered k8s version : v1.19.9
  Discovered MTU         : 1376
  Idle :
    bandwidth = 0 Mbit/s
    client cpu = total 5.80% (user 3.37%, nice 0.00%, system 1.68%, iowait 0.75%, steal 0.00%)
    server cpu = total 3.45% (user 2.19%, nice 0.00%, system 0.88%, iowait 0.38%, steal 0.00%)
    client ram = 1304 MB
    server ram = 1352 MB
  Pod to pod :
    TCP :
      bandwidth = 3438 Mbit/s
      client cpu = total 18.24% (user 2.37%, nice 0.00%, system 15.36%, iowait 0.51%, steal 0.00%)
      server cpu = total 27.32% (user 1.16%, nice 0.00%, system 25.88%, iowait 0.28%, steal 0.00%)
      client ram = 1308 MB
      server ram = 1351 MB
    UDP :
      bandwidth = 1820 Mbit/s
      client cpu = total 27.57% (user 3.36%, nice 0.00%, system 23.64%, iowait 0.57%, steal 0.00%)
      server cpu = total 31.07% (user 3.51%, nice 0.00%, system 27.18%, iowait 0.38%, steal 0.00%)
      client ram = 1308 MB
      server ram = 1352 MB
  Pod to Service :
    TCP :
      bandwidth = 3548 Mbit/s
      client cpu = total 19.13% (user 2.41%, nice 0.00%, system 16.29%, iowait 0.43%, steal 0.00%)
      server cpu = total 26.05% (user 1.58%, nice 0.00%, system 24.22%, iowait 0.25%, steal 0.00%)
      client ram = 1315 MB
      server ram = 1353 MB
    UDP :
      bandwidth = 1716 Mbit/s
      client cpu = total 26.88% (user 3.29%, nice 0.00%, system 23.21%, iowait 0.38%, steal 0.00%)
      server cpu = total 27.00% (user 3.30%, nice 0.00%, system 23.40%, iowait 0.30%, steal 0.00%)
      client ram = 1317 MB
      server ram = 1353 MB
=========================================================

How to reproduce it?

1. download Rancher and start a new cluster with weave and set MTU to 1376

Anything else we need to know?

Versions:

Rancher 2.5.7 Weave 2.7.0 K8S 1.19.9 Ubuntu 20.04.2 LTS Docker 20.10.3

[maxisam]

Test it with 2.8.1.