[dm-devel] [git pull] device mapper changes for 5.9

[Linus Torvalds]

On Tue, Aug 18, 2020 at 2:12 PM Ignat Korchagin <ignat at cloudflare.com> wrote:
>
> Additionally if one cares about latency

I think everybody really deep down cares about latency, they just
don't always know it, and the benchmarks are very seldom about it
because it's so much harder to measure.

> they will not use HDDs for the workflow and HDDs have much higher IO latency than CPU scheduling.

I think by now we can just say that anybody who uses HDD's don't care
about performance as a primary issue.

I don't think they are really interesting as a benchmark target - at
least from the standpoint of what the kernel should optimize for.

People have HDD's for legacy reasons or because they care much more
about capacity than performance.  Why should _we_ then worry about
performance that the user doesn't worry about?

I'm not saying we should penalize HDD's, but I don't think they are
things we should primarily care deeply about any more.

               Linus