Re: [PATCH 4/4] arm64: dts: rockchip: Add OPP data for CPU cores on RK3588

[Dragan Simic]

Hello Alexey,

On 2024-01-29 01:09, Dragan Simic wrote:
> On 2024-01-28 20:14, Alexey Charkov wrote:
> > On Sun, Jan 28, 2024 at 7:35 AM Dragan Simic <dsimic@xxxxxxxxxxx> 
> > wrote:
> > > Just checking, running the test on just two CPU cores was enough to
> > > keep the package temperature at around 80 oC?
> >
> > No, not even remotely.
> >
> > I kept the continuous 6 dhrystone threads running on all the other
> > cores (`taskset -c 0-5 ./dhrystone -t 6 -r 6000`) to let it reach the
> > throttling temperature. This adds further imprecision to the benchmark
> > of course, because the governor might choose to throttle some of the
> > cores that do not participate in the timed benchmarking run, and thus
> > lend some thermal headroom to the latter. That didn't seem to happen
> > from my naked-eye observation via `watch "cpupower -c 0,4,6
> > frequency-info | grep current"`, although I admit that I didn't record
> > more granular logs of frequency states, and some quick transitions to
> > lower frequencies could also have happened on the other cores. Don't
> > think it's a major influence though, because a quick transition back
> > and forth shouldn't have contributed much to the thermal output.
>
> Thank you for the clarification!
>
> You're right, that might have introduced some inaccuracy into the test
> results, and it also made the tests kind of hardly repeatable.  On the
> other hand, that way the synthetic CPU test feels a bit more like some
> real-world CPU load, in which multiple resource-hungry tasks usually
> compete for the CPU cores and the thermal budget.
>
> Though, as we know repeatability is the key for a scientific approach,
> but it also usually contradicts with simulating real-world loads that
> are of rather random nature.  Well, testing is hard. :)
>
> I'll think a bit more about all this, and I'll come back with an 
> update.
> Maybe I'll also be able to join the testing.

Good news! :)  Thanks to Radxa, I'll be able to do the testing on my
side, perhaps in about a week or two.  If you agree, it might be the 
best
to wait for those test results as well;  of course, I'll keep thinking
about some kind of a test suite in the meantime, which we should be able
to use on other boards as well.