Re: [PATCH] drm/lima: add governor data with pre-defined thresholds

[Lukasz Luba]

On 1/27/21 7:35 PM, Christian Hewitt wrote:
> > On 27 Jan 2021, at 3:11 pm, Lukasz Luba <lukasz.luba@xxxxxxx> wrote:
> >
> > On 1/27/21 10:24 AM, Lukasz Luba wrote:
> > > Hi Christian,
> > > On 1/25/21 8:18 AM, Christian Hewitt wrote:
> > > > This patch adapts the panfrost pre-defined thresholds change [0] to the
> > > > lima driver to improve real-world performance. The upthreshold value has
> > > > been set to ramp GPU frequency to max freq faster (compared to panfrost)
> > > > to compensate for the lower overall performance of utgard devices.
> > > >
> > > > [0] https://patchwork.kernel.org/project/dri-devel/patch/20210121170445.19761-1-lukasz.luba@xxxxxxx/
> > > >
> > > > Signed-off-by: Christian Hewitt <christianshewitt@xxxxxxxxx>
> > > > ---
> > > > I have been using Kodi as my test application. If you scroll in library
> > > > views with hundreds of list items and the panfrost values the slow GPU
> > > > ramp up is quite noticeable and the GUI feels sluggish. As everything
> > > > lima runs on is inherently slower than panfrost using devices I believe
> > > > it's better to ramp up to max freq quicker.
> > > It's quite low value for the upthreshold, but I believe you have
> > > experimented and observed that a bit higher (30, 40?) don't work well.
> > > I don't know the Kodi system, though.
> > > You can check if the other frequencies are also used in statistics for
> > > devfreq device:
> > > cat /sys/class/devfreq/<your_gpu>/trans_stats
> > > If they are also used, then it OK (better than stuck at min freq).
> >
> > I've just realized that your board might suffer a another issue.
> > Please apply this patch [1] and run your experiments with upthresholds.
> >
> > [1] https://lore.kernel.org/lkml/20210127105121.20345-1-lukasz.luba@xxxxxxx/
>
> I’ve included the patch and with unscientific testing it feels snappier with a larger value than
> before. I did revert back to 45 first, but again this feels sluggish when navigating around the
> Kodi GUI. My main test is to enter ‘Movies’ in Kodi then start scrolling in a long list. When
> the GPU ramps up quickly the experience is snappy, but when it ramps more conservatively
> scrolling feels like it stutters, then (once you hit max freq) it becomes fluid.
>
> WP2:~ # cat /sys/class/devfreq/d00c0000.gpu/trans_stat
>       From  :   To
>             : 125000000 250000000 285714285 400000000 500000000 666666666 744000000   time(ms)
> * 125000000:         0         0         0         0         0         0       264     52720
>    250000000:         9         0         0         0         0         0        36      3404
>    285714285:         9         3         0         0         0         0        32      2628
>    400000000:        18        20        13         0         0         0       191     21140
>    500000000:        12        12         8        63         0         0        31     10068
>    666666666:       179         5        16       133        66         0        24     29360
>    744000000:        37         5         7        46        60       423         0     46016
>
> I’ll send v2 with the value set to 30.

Thank you Christian for re-testing it and attaching the stats. It looks
good. I'll add my reviewed-by for v2 patch.

Regards,
Lukasz