Re: [PATCH 08/10] drm/tegra: Implement dynamic channel allocation model

[Mikko Perttunen]

On 05.11.2017 19:43, Dmitry Osipenko wrote:
> On 05.11.2017 14:01, Mikko Perttunen wrote:
> > In the traditional channel allocation model, a single hardware channel
> > was allocated for each client. This is simple from an implementation
> > perspective but prevents use of hardware scheduling.
> >
> > This patch implements a channel allocation model where when a user
> > submits a job for a context, a hardware channel is allocated for
> > that context. The same channel is kept for as long as there are
> > incomplete jobs for that context. This way we can use hardware
> > scheduling and channel isolation between userspace processes, but
> > also prevent idling contexts from taking up hardware resources.
>
> The dynamic channels resources (pushbuf) allocation is very expensive,
> neglecting all benefits that this model should bring at least in non-IOMMU case.
> We could have statically preallocated channels resources or defer resources freeing.

This is true. I'll try to figure out a nice way to keep the pushbuf 
allocations.

> > For now, this patch only adapts VIC to the new model.
>
> I think VIC's conversion should be a distinct patch.

Sure.

Cheers,
Mikko