On 08/12/2020 13:22, Javier González wrote:

Good idea. Are you thinking of a sysfs entry to select the backend?

Not sure on this one, initially I thought of a sysfs file, but then
how would you do it. One "global" sysfs entry is probably a bad idea.
Having one per block device to select native vs emulation maybe? And
a good way to benchmark.

The other idea would be a benchmark loop on boot like the raid library
does.

Then on the other hand, there might be workloads that run faster with 
the emulation and some that run faster with the hardware acceleration.

I think these points are the reason the last attempts got stuck.