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

Daniel Jordan
2018-12-01T00:13:07Z

On Fri, Nov 30, 2018 at 11:18:19AM -0800, Tejun Heo wrote:
> Hello,
>
> On Mon, Nov 05, 2018 at 11:55:45AM -0500, 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.
>
> Have you tested what kind of impact this has on bandwidth of a system
> in addition to latency? The thing is while this would make a better
> use of a system which has idle capacity, it does so by doing more
> total work. It'd be really interesting to see how this affects
> bandwidth of a system too.

I guess you mean something like comparing aggregate CPU time across threads to
the base single thread time for some job or set of jobs? Then no, I haven't
measured that, but I can for next time.