[dm-devel] [RFC PATCH v2 0/2] add simple copy support

[Javier González]

On 08.12.2020 08:40, Johannes Thumshirn wrote:
>On 07/12/2020 20:27, Javier González wrote:
>> Good point. We can share some performance data on how Simple Copy scales
>> in terms of bw / latency and the CPU usage. Do you have anything else in
>> mind?
>>
>
>With an emulation in the kernel, we could make the usd "backend"
>implementation configurable. So if the emulation is faster, users can select
>the emulation, if the device is faster then the device.
>
>Kind of what the crypto and raid code do as well.

Good idea. Are you thinking of a sysfs entry to select the backend?
>
>I'm really interested in this work, as BTRFS relocation/balance will have
>potential benefits, but we need to get it right.

Agree. We will post a V3 with emulation and addressing other comments.
We can take it from there. If you have comments on V2, please send them
our way and we will take them in.