RFR: 8251854: [macosx] Java forces the use of discrete GPU

[Victor Dyakov]

On Tue, 17 Nov 2020 18:55:51 GMT, Sergey Bylokhov <serb at openjdk.org> wrote:

>> I ran a 3D lighting test that is designed to be a GPU stress test. It's a worst case, to be sure, but it take 10 times as long to render with the integrated GPU as it does with the discrete GPU:
>> 
>> **attenuation.LightingSample: 500 large quads**
>> discrete GPU: 23.5 fps
>> integrated GPU: 2.34 fps
>> 
>> In a more realistic example of drawing a large number of 2D vectors, it runs 35% slower with the integrated GPU:
>> 
>> **Vector charting test, oval clip**
>> discrete GPU: 41.1 fps
>> integrated GPU: 26.6 fps
>> 
>> I see similar results in the performance numbers you listed above.
>> 
>> An application developer who packages up their JDK, for example, using jpackage, can make the decision for themselves. Application developers who rely on the JDK as delivered will get whatever we choose as the default. So we need to be sure that the benefit of doing this justifies the performance hit.
>
>> > @kevinrushforth @prrace could you please review?
>> 
>> As we discussed yesterday, it is reviewed but not ready to be approved.
>> We are waiting for a reply from Apple.
> 
> @prrace 
> We are waiting for it for three months already. If it is possible then not sure why other applications did not found any possible ways to force one specific GPU. What we are wating for?

@mrserb @prrace  what is a back up plan in case we will not have a reply from Apple? (as we do not have it for 4! months). Definitely we need a plan B

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PR: https://git.openjdk.java.net/jdk/pull/1139