[dm-devel] Significantly dropped dm-cache performance in 4.13 compared to 4.11

[Joe Thornber]

On Fri, Nov 03, 2017 at 07:50:23PM +0100, Stefan Ring wrote:
> It strikes me as odd that the amount read from the spinning disk is
> actually more than what comes out of the combined device in the end.

This suggests dm-cache is trying to promote too way too much.
I'll try and reproduce the issue, your setup sounds pretty straight forward.

- Joe