Re: [LAD] Android audio plugins

From: Nick Copeland <nickycopeland@email-addr-hidden>
Date: Wed Jun 29 2011 - 23:33:02 EEST

> No, when building with Android NDK using the armeabi-v7a ABI, hard floats are
> used. This works on ARMv7, which means a lot of devices, and certainly the
> majority.

But then every other system gets the rough 1000 factor performance hit that started
this thread since all other CPU have to do a system call to execute the float operation.
Designing for a single handset family is not that scalable.

> > The ARM
> > softfloat overhead is not that great and the coding required to get
> > access to the GPUs is suitable that developers will implement them
> > for optimisations.
>
> Soft floats are insanely slow on Android in my experience.

A factor of 10 or 20 over hard floats? Sound about right? The factor 1000 is for code
that uses FPU instructions on systems without the FPU support. That I would call
insanely slow but you can choose which way you go here.

> You got an FPU on most devices, you can compile for hard floats, activate ARM
> NEON if you wish too, and even check for cpu features at runtime. I don't see
> why you want to use the GPU for optimization.

Man, the recent chipsets have 6 of these pipelines - designed for graphics processing
but sitting there waiting for audio DSP.

Regards, nick.
                                               

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Received on Thu Jun 30 00:15:04 2011

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