On 04.06.2012 20:29, Jerome Glisse wrote:
On Mon, Jun 4, 2012 at 2:18 PM, Jerome Glisse<j.glisse@xxxxxxxxx> wrote:
Yeah, I get your point as a kernel dev, but I pitty the userspace dev that
will need to figure out how to use all these ioctls and configuration
options.
My point there is that we do the userspace bit, i would like to come
up with some kind of module that thing like gnome-control-center can
use or kde equivalent or anyother desktop environment.
A GUI will be needed, but I thought it would be much simpler to share
as much of the PM interface as possible.
If you hear about someone starting the project, I'll be glad to give some
input and contribute some code too for Nouveau.
What about having a simple common API (sysfs, preferably) that allow to
change
the performance profile and leave the rest to drivers?
Would that be acceptable?
Cheers,
Martin
I think a powerprofile file is acceptable, i am not sure if it should
be discrete like performance/normal/battery/low or something more like
a scale 0-10 with 10 being full power and 0 being the lowest power the
GPU can do. I am more incline to the word solution for which we can
gave clear definition like :
low : power mode is only able to meet the need of one light graphical
application (like video playback) expect some sluggishness in
rendering when switching between application.
battery: save as much power and reduce GPU speed while still allowing
fast desktop reactivity
...
Just like you, my mind is mixed. However, I don't think
"performance/normal/battery/low" is a good way to put it.
I would go for something like that:
low (static, clocked to the lowest)
conservative (DVFS but slow to upclock, instant declock) : default for
battery
normal (DVFS, instant upclock and declock)
performance (DVFS, instant upclock and slow declock) : default for sector
benchmark (static, clocked to the highest)
slow ~= 100ms, instant == less than a frame
The hardest part will be upclocking the GPU right to where it isn't a
bottleneck anymore.
Cheers,
Jerome
Maybe i should stress that i believe that driver can't efficiently do
quick reclocking when it comes to GPU. My understanding is that newer
GPU wether AMD or NVidia use some kind of controller that use a small
firmware to control power adjustment base on GPU usage on the flight.
Those firmware use driver input to determine range of operation
(max/min voltage/frequency/fan speed/...) What i want to allow is for
userspace to customize and know about those range of operations. A
power profile is just a set of range (a range might be a single value
on some less adjustable GPU) for each of the adjustable parameters.
Exactly my thoughts too :) PDAEMON is a 200MHz engine
that has full access to MMIO. We can get and generate IRQs
from/for the host. It can access performance counters
but it seems like it also has some performance counters of his own.
The only problem is that we have no good compiler for this ISA.
The ISA was reverse engineered by mwk, we have a good
assembler.
So I'm trying to keep things as simple as possible for maintainability :D
FYI: https://gitorious.org/pdaemon/pdaemon/blobs/master/pdaemon.fuc
Anyway, we are in the same mindset, so let's implement what we both of us
have in mind and see how we can share things when we are done with
our toy implementations, we can try to compare our solutions.
Cheers,
Jerome
Martin
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/dri-devel
