[OpenJDK 2D-Dev] RFR: 8251854 [macosx] Java forces the use of discrete GPU

Kevin Rushforth kevin.rushforth at oracle.com
Tue Aug 25 23:22:08 UTC 2020

On 8/25/2020 4:17 PM, Sergey Bylokhov wrote:
> On 25.08.2020 16:08, Kevin Rushforth wrote:
>> I haven't tested an FX app yet, but since this changes the plist 
>> properties, I want to see whether or not FX apps are impacted.
> It should be affected because the first variation of the fix was 
> pushed to the FX(if nothing changed since then):
> https://bugs.openjdk.java.net/browse/JDK-8132775
> Since FX does not have the launcher it depends on the "bin/java" or 
> the packed application.

Yes, this is what I remember as well back when we were testing the bug. 
My recollection is that we only wanted to avoid using the discrete CPU 
when running on battery, although it's been a while since we first 
looked at this.

-- Kevin

>> -- Kevin
>> On 8/25/2020 4:01 PM, Sergey Bylokhov wrote:
>>> On 25.08.2020 15:40, Philip Race wrote:
>>>> On 8/25/20, 12:27 PM, Sergey Bylokhov wrote:
>>>>> On 25.08.2020 05:43, Kevin Rushforth wrote:
>>>>>> Does this only apply when the MacBook is running on battery, or 
>>>>>> will this affect performance even when the laptop is plugged in? 
>>>>>> If the latter, I wonder what Apple's rationale is for including a 
>>>>>> discrete graphics card that isn't used most of the time.
>>>> Based on the numbers, I wonder if we should make this change ?
>>> This is how other applications work, some numbers are now aligned to 
>>> the metal pipeline.
>>> Also results are similar to other macbooks without discrete graphics.
>>>>> It is applied if the "automatic graphics switching" is enabled, if 
>>>>> the user disables
>>>>> this feature for the "power adapter" mode, then the discrete 
>>>>> graphics will be always used.
>>>> That's a bit misleading
>>>> If I disable automatic graphics switching it is disabled for BOTH 
>>>> batter and power
>>>> and vice versa. In other words there is no way to express that 
>>>> battery power should fall back
>>>> to integrated and that you only want discrete when running on the 
>>>> adapter.
>>> It is possible to do it manually, in the "power adapter" mode the 
>>> user can disable
>>> "automatic graphics switching", and enable it in the "battery" mode.
>>> BTW I have never did it myself.

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