Re: [RFC PATCH v4 00/13] ktask: multithread CPU-intensive kernel work

Daniel Jordan
2018-11-06T01:29:55Z

On Mon, Nov 05, 2018 at 06:29:31PM +0100, Michal Hocko wrote:
> On Mon 05-11-18 11:55:45, Daniel Jordan wrote:
> > Michal, you mentioned that ktask should be sensitive to CPU utilization[1].
> > ktask threads now run at the lowest priority on the system to avoid disturbing
> > busy CPUs (more details in patches 4 and 5). Does this address your concern?
> > The plan to address your other comments is explained below.
>
> I have only glanced through the documentation patch and it looks like it
> will be much less disruptive than the previous attempts. Now the obvious
> question is how does this behave on a moderately or even busy system
> when you compare that to a single threaded execution. Some numbers about
> best/worst case execution would be really helpful.

Patches 4 and 5 have some numbers where a ktask and non-ktask workload compete
against each other. Those show either 8 ktask threads on 8 CPUs (worst case) or no ktask threads (best case).

By single threaded execution, I guess you mean 1 ktask thread. I'll run the
experiments that way too and post the numbers.

> I will look closer later.

Great! Thanks for your comment.

Daniel