pisces, produceFillAlphas

[Johan Vos]

Thanks Jim.
I tried with different optimization flags, but it doesn't make a big
difference. Tracing it down to system calls, somehow the gl implementation
seems be be slower (glDrawElements(GL_TRIANGLES, numQuads * 2 * 3,
GL_UNSIGNED_SHORT, 0) takes more time on Android than on iOS) per
invocation. The number of invocations is comparable between iOS and Android.

If you can give me a direction on where to search for the disabled
scrolling optimization, I'll try to re-enable that and see how it improves
performance. It might be a huge and quick win...

Thanks again,

- Johan

On Thu, Oct 15, 2015 at 9:02 PM, Jim Graham <james.graham at oracle.com> wrote:

> Perhaps optimization flags with the native compiler?  Also, was it called
> a similar number of times on both?
>
> Ideally we'd just be using copyArea for the scrolling, but at one point we
> disabled the scrolling optimizations on retina MBP because they didn't work
> with a scale factor and I don't think we reenabled them yet.  That would
> kill scrolling performance on mobile as a result of having to rerender the
> scene on each scroll regardless of how long produceAlphas takes...
>
>                         ...jim
>
>
> On 10/15/15 4:27 AM, Johan Vos wrote:
>
>> After spending lots of time optimizing JavaFX on iOS, I am now at the
>> point
>> where scrolling is 10 times faster on iOS than on Android.
>> The scrolling in the iOS version of the Gluon JavaOne mobile schedule
>> builder is pretty good imho. On Android, it is much slower. I profiled and
>> compared both, and it turns out that on Android, we spend lots of time in
>> the native implementation of NativePiscesRasterizer.produceFillAlphas
>> (implemented in native-prism/NativePiscesRasterizer.c)
>>
>> On average, calling this native function on an iPhone 6 takes 40,000ns
>> whereas on a Nexus 6, this takes about 800,000ns.
>>
>> If anyone has a suggestion on how to improve or avoid this, I'm all ears.
>>
>> Thanks,
>>
>> - Johan
>>
>>