[PATCH v10 07/11] drm/etnaviv: Add support for the dma coherent device

[Sui Jingfeng]

Hi

On 2023/6/21 23:58, Lucas Stach wrote:
>> you approach forbidden any possibility to use the WC BO at anywhere.
>>
>>
>> My approach need only check once, while you approach need at least 3
>> check plus
>>
>> so much bit-wise logic operations,  plus a function call  (&, ==, &&,
>> &, ~, &) .
>>
>> and every time you create a BO. This nasty judgement happens.
>>
> BO creation again is not a fast path. You are committing to allocate
> new memory, which is a few orders of magnitude more costly than the few
> instructions needed for those comparisons.
>
What's wrong with you point here is that

We are not going make it more worse because it is worse.

We would like same any single bit of the performance.


It's about the beauty, and beauty and correctness is every thing.


My implement is good both in the perspective of beauty and in the 
perspective of the performance.

BO creation is fast or not is irrelevant to what the point we are discuss.

You are always introduce non-critical factor to disturb the discuss,

leading the people go a wrong direction.

-- 
Jingfeng