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

[Mikko Perttunen <cyndis@kapsi.fi>]

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