how to increase the vnet speed?

From: Benoit Chesneau <benoitc_at_enki-multimedia.eu>
Date: Tue, 23 May 2023 19:58:07 UTC 
Hi all,

I've created a jail using bastille and setup network. The mainin terface is a 25Gbps nic and between hosts I get 24.6 Gbits/sec :

[ ID] Interval Transfer Bitrate[ 5] 0.00-1.00 sec 2.87 GBytes 24.6 Gbits/sec
[ 5] 1.00-2.00 sec 2.88 GBytes 24.7 Gbits/sec
[ 5] 2.00-3.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 3.00-4.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 4.00-5.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 5.00-6.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 6.00-7.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 7.00-8.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 8.00-9.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 9.00-10.00 sec 2.87 GBytes 24.7 Gbits/sec
[ 5] 10.00-10.00 sec 128 KBytes 17.2 Gbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate
[ 5] 0.00-10.00 sec 28.7 GBytes 24.7 Gbits/sec receiver

But between one host and the jail I only get 3.96 Gbits/sec

ID] Interval Transfer Bitrate Retr Cwnd[ 5] 0.00-1.00 sec 477 MBytes 4.00 Gbits/sec 44 278 KBytes
[ 5] 1.00-2.00 sec 455 MBytes 3.82 Gbits/sec 41 215 KBytes
[ 5] 2.00-3.00 sec 463 MBytes 3.89 Gbits/sec 61 391 KBytes
[ 5] 3.00-4.00 sec 488 MBytes 4.10 Gbits/sec 39 336 KBytes
[ 5] 4.00-5.00 sec 484 MBytes 4.06 Gbits/sec 30 253 KBytes
[ 5] 5.00-6.00 sec 448 MBytes 3.76 Gbits/sec 44 355 KBytes
[ 5] 6.00-7.00 sec 454 MBytes 3.81 Gbits/sec 56 266 KBytes
[ 5] 7.00-8.00 sec 471 MBytes 3.95 Gbits/sec 41 325 KBytes
[ 5] 8.00-9.00 sec 500 MBytes 4.20 Gbits/sec 39 321 KBytes
[ 5] 9.00-10.00 sec 475 MBytes 3.98 Gbits/sec 42 367 KBytes
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.00 sec 4.61 GBytes 3.96 Gbits/sec 437 sender
[ 5] 0.00-10.00 sec 4.61 GBytes 3.96 Gbits/sec receiver

Is there a way to increase the performance of the of the jail? The nice is a mellannox ConnectX-4 Lx, mce(4) .

Benoît