Question about per process GPU context global priority enforcement

[Yiwei Zhang]

Instead of reusing CAP_SYS_NICE. Is there any on-going efforts to
unify this inside the drm cgroup controller? The controller I'm
referring to is this one currently used for setting gem buffer limits:
https://lists.freedesktop.org/archives/amd-gfx/2019-June/036026.html

Is it possible that a new controller can be introduced for this purpose?

On Wed, Aug 5, 2020 at 12:26 PM Yiwei Zhang <zzyiwei at google.com> wrote:
>
> Let me add more context. On Android, systemui and launcher should be
> allowed to create high priority gpu contexts while the normal random
> applications must be ceiled to default priority. However, systemui and
> launcher are not allowed to create realtime threads so we can't grant
> them CAP_SYS_NICE. Thus either a new cgroup is needed in this case or
> we add sysui/launcher into some other present cgroup for the gfx
> kernel driver to distinguish.
>
> On Wed, Aug 5, 2020 at 4:47 AM Bas Nieuwenhuizen
> <bas at basnieuwenhuizen.nl> wrote:
> >
> > I don't think we have a uniform mechanism, currently each driver
> > decides on their own.
> >
> > For the amdgpu driver we check that the process either has
> > CAP_SYS_NICE or is the DRM master.
> >
> > On Wed, Aug 5, 2020 at 9:14 AM Yiwei Zhang <zzyiwei at google.com> wrote:
> > >
> > > Hi friends,
> > >
> > > For Vulkan/EGL, upon creating gpu contexts, applications can ask for a
> > > system-wide higher priority levels via VK_EXT_global_priority or
> > > EGL_IMG_context_priority extensions.
> > >
> > > I'm curious if we have certain rules(some form of process privilege
> > > check) in the kernel to limit non-privileged ones to never go beyond
> > > default system-wide gpu scheduling priority. (e.g. not allow random
> > > app processes to contend the GPU queues repeatedly/infinitely with
> > > high/realtime priorities)
> > >
> > > Many thanks,
> > > Yiwei - from Android Platform Graphics Team
> > > _______________________________________________
> > > dri-devel mailing list
> > > dri-devel at lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/dri-devel