Changes to let KFD use render node VMs

[Christian König]

Am 02.03.2018 um 07:59 schrieb zhoucm1:
>
>
> On 2018年03月02日 14:19, Kuehling, Felix wrote:
>> Hi David,
>>
>> Compute contexts enable the compute power profile,
> I heard from Rex, he said he prefer power profile depends on ring 
> busy/idle, rather than always enable it.
>
>> and can use a different VM update mode from graphics contexts (SDMA 
>> vs. CPU).
> If we can identify which is faster and efficient, then we can unify it 
> I guess.

Well SDMA is a bit faster in some cases, can access all of VRAM and is 
pipelined.

CPU has lower latency, but it can't access all of VRAM and isn't pipelined.

Lower latency is important for KFD and that it is pipelined is very 
important for good GFX performance.

Regards,
Christian.

>
>
> Anyway, thanks for explain.
> David Zhou
>> These differences are not going away. Not yet, anyway. If we start 
>> sharing VM address space between graphics and compute in the future, 
>> this will have to change. That is, these features would have to be 
>> controlled by other means than by the vm context.
>>
>> Regards,
>>    Felix
>>
>> ________________________________________
>> From: amd-gfx <amd-gfx-bounces at lists.freedesktop.org> on behalf of 
>> zhoucm1 <zhoucm1 at amd.com>
>> Sent: Thursday, March 1, 2018 10:18:15 PM
>> To: Kuehling, Felix; amd-gfx at freedesktop.org; Koenig, Christian
>> Subject: Re: Changes to let KFD use render node VMs
>>
>> Hi Felix,
>>
>> Out of patches, Could I ask what the difference of 
>> AMDGPU_VM_CONTEXT_COMPUTE/GFX is?
>>
>> After you merge kfd_vm to amdgpu_vm, does the difference still exist?
>>
>>
>> Thanks,
>>
>> David Zhou
>>
>> On 2018年03月02日 06:58, Felix Kuehling wrote:
>>
>> Hi Christian,
>>
>> I have a working patch series against amd-kfg-staging that lets KFD use
>> VMs from render node FDs, as we discussed. There are two patches in that
>> series that touch amdgpu_vm.[ch] that I'd like your feedback on before I
>> commit the changes to amd-kfd-staging and include them in my upstream
>> patch series for KFD GPUVM support. See attached.
>>
>> Thanks,
>>    Felix
>>
>>
>>
>>
>>
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>>
>