[ 1.309292] raid6: using algorithm avx2x4 gen() 0 MB/s [ 1.311507] raid6: .... xor() 0 MB/s, rmw enabled [ 1.313702] raid6: using avx2x2 recovery algorithm [ 1.315971] xor: automatically using best checksumming function avx [ 1.338371] Btrfs loaded, crc32c=crc32c-generic
This has mostly something to do with your cpu...
Which cpu are you using?
So you're running openwrt as a kvm virtualized host on which real cpu?
Can you also post a full output of
/proc/cpuinfo from your virtualized openwrt?
I assume further that the "benchmark" for avx2x2 does has anything other than 0 MB/s, right?
As you see in the flags row of
/proc/cpuinfo, your virtualized cpu doesn't have the avx2 instructions.
Probably if you select another cpu type for your vm, you will have avx2 in your vm.
But if your host cpu doesn't have the avx2 instructions, you can't have it in your vm's vcpu.
You doesn't tell us something about your host cpu as requested, so we can't tell you if it's possible to get the avx2 instructions in your vm.