Posting my results:
XCP ng stable 8.2, up-to-date.
Epyc 7402 (1 socket)
512GB RAM 3200Mhz
Supermicro h12ssl-i
No cpu pinning
VM's: Ubuntu 22.04 Kernel 6.5.0-41-generic
v2m 1 thread: 3.5Gb/s - Dom0 140%, vm1 60%, vm2 55%
v2m 4 threads: 9.22Gb/s - Dom0 555%, vm1 320%, vm2 380%
h2m 1 thread: 10.4Gb/s - Dom0 183%, vm1 180%, vm2 0%
h2m 4 thread: 18.0Gb/s - Dom0 510%, vm1 490%, vm2 0%
host : xcp-ng-7402
release : 4.19.0+1
version : #1 SMP Tue Jan 23 14:12:55 CET 2024
machine : x86_64
nr_cpus : 48
max_cpu_id : 47
nr_nodes : 1
cores_per_socket : 24
threads_per_core : 2
cpu_mhz : 2800.047
hw_caps : 178bf3ff:7ed8320b:2e500800:244037ff:0000000f:219c91a9:00400004:00000500
virt_caps : pv hvm hvm_directio pv_directio hap shadow
total_memory : 524149
free_memory : 39528
sharing_freed_memory : 0
sharing_used_memory : 0
outstanding_claims : 0
free_cpus : 0
cpu_topology :
cpu: core socket node
0: 0 0 0
1: 0 0 0
2: 1 0 0
3: 1 0 0
4: 2 0 0
5: 2 0 0
6: 4 0 0
7: 4 0 0
8: 5 0 0
9: 5 0 0
10: 6 0 0
11: 6 0 0
12: 8 0 0
13: 8 0 0
14: 9 0 0
15: 9 0 0
16: 10 0 0
17: 10 0 0
18: 12 0 0
19: 12 0 0
20: 13 0 0
21: 13 0 0
22: 14 0 0
23: 14 0 0
24: 16 0 0
25: 16 0 0
26: 17 0 0
27: 17 0 0
28: 18 0 0
29: 18 0 0
30: 20 0 0
31: 20 0 0
32: 21 0 0
33: 21 0 0
34: 22 0 0
35: 22 0 0
36: 24 0 0
37: 24 0 0
38: 25 0 0
39: 25 0 0
40: 26 0 0
41: 26 0 0
42: 28 0 0
43: 28 0 0
44: 29 0 0
45: 29 0 0
46: 30 0 0
47: 30 0 0
device topology :
device node
No device topology data available
numa_info :
node: memsize memfree distances
0: 525554 39528 10
xen_major : 4
xen_minor : 13
xen_extra : .5-9.40
xen_version : 4.13.5-9.40
xen_caps : xen-3.0-x86_64 hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xffff800000000000
xen_changeset : 708e83f0e7d1, pq 9a787e7255bc
xen_commandline : dom0_mem=8192M,max:8192M watchdog ucode=scan dom0_max_vcpus=1-16 crashkernel=256M,below=4G console=vga vga=mode-0x0311
cc_compiler : gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-28)
cc_compile_by : mockbuild
cc_compile_domain : [unknown]
cc_compile_date : Thu Apr 11 18:03:32 CEST 2024
build_id : fae5f46d8ff74a86c439a8b222c4c8d50d11eb0a
xend_config_format : 4