Re: [PATCH v20 00/12] Implement copy offload support

[Hannes Reinecke]

On 6/4/24 06:32, Christoph Hellwig wrote:
> On Mon, Jun 03, 2024 at 10:53:39AM +0000, Nitesh Shetty wrote:
> > The major benefit of this copy-offload/emulation framework is
> > observed in fabrics setup, for copy workloads across the network.
> > The host will send offload command over the network and actual copy
> > can be achieved using emulation on the target (hence patch 4).
> > This results in higher performance and lower network consumption,
> > as compared to read and write travelling across the network.
> > With this design of copy-offload/emulation we are able to see the
> > following improvements as compared to userspace read + write on a
> > NVMeOF TCP setup:
>
> What is the use case of this?   What workloads does raw copies a lot
> of data inside a single block device?

The canonical example would be VM provisioning from a master copy.
That's not within a single block device, mind; that's more for copying 
the contents of one device to another.
But I wasn't aware that this approach is limited to copying within a 
single block devices; that would be quite pointless indeed.

Cheers,

Hannes
--
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@xxxxxxx                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich