Linaro doubles performance for Android ICS

http://www.androidpolice.com/2012/06/09/linaro-android-nearly-doubles-ics-performance-and-now-parts-of-it-are-being-added-to-cm9/

by TobbenTM • 14 years ago

77 16 14 years ago

androidpolice.com

DiabloD3• 14 years ago

Notice that says "doubles over stock". OEMs are notorious for not properly configuring builds, so the real question is: how well does it perform against devices that already run some CM9-based build.

mtgx• 14 years ago

Well that point will be moot soon since CM9 will incorporate the optimization, but I wonder if Google will use it, too.

Tanner• 14 years ago

The reddit thread has some benchmarks: http://www.reddit.com/r/GalaxyNexus/comments/usos8/linaro_op...

buster• 14 years ago

The article mentions notably faster on Galaxy Nexus.

trun• 14 years ago

What does this do to battery life?

maratd• 14 years ago

You're dealing with a higher quality build, so I would imagine you would have a bit more free space and bit more battery life.

mitchellh• 14 years ago

So what exactly did they do technically to double the performance of stock ICS?

I read the article and watched a few minutes of the video and there was no detailed answer. The article itself didn't seem to link to any detailed resource either.

edderly4• 14 years ago

It's not double the performance. It's a demo that if you use the software GLES implementation (which isn't used in production) they can run that benchmark at 60fps. The non-linaro toolchain GLES renders at less that 60 fps for this benchmark and then degrades to 30fps because the setup is double buffered and vsync'd.

barrkel2• 14 years ago

Vsync doesn't convert anything in the range of 31..59 FPS to 30 FPS. Vsync prevents fractional frame updates. You can still have any integer number of frames per second with vsync enabled. Anything less than 60FPS will just look like a dropped frame.

(Double-buffering isn't particularly relevant to FPS that I can see. It just prevents you seeing the frame while it's being drawn, in practice it's mostly useful for reducing flicker from overdraw.)

saurik• 14 years ago

Everyone is saying "nothing", but I reviewed the patches (I did /not/ bother watching the video, however, as it was long and I was in a place where I felt uncomfortable playing sound; so maybe the video says "we didn't do anything" ;P), and what they did is to remove all of the non-strict pointer aliasing (one of C's optimization weaknesses) and thereby were able to kick the optimizer up to -O3, which is helping some already tightly-coded algorithms actually avoid touching memory.

edderly4• 14 years ago

What's being demonstrated here isn't a real world usecase rather it is a demonstration that software (cpu based) GLES implementation can run at 60 fps with this test. In the production devices (and also available on Panda too) the actual GPU driver/libraries for the SGX540 is used.

Practically this means that the Linaro tool chain won't double the performance of this test on a fuller environment.

Additionally it's fairly specious to say 'double' the performance, on Android things are typically vsync'd and double buffered so if you render at < 60fps you will degrade to 30fps.

IMO this is mildly disingenuous or at best naive and from a technical perspective Linaro should really do a better job trying to make their efforts relevant.

They'd be better off showing off improvements in browser performance because the CPU is still used for some 2D rendering.

krakensden• 14 years ago

Does Android even use software GLES? I thought 3/4 of the point of modern smartphones was that they came with GPUs.

james_lan• 14 years ago

Actually, in many cases Android does use the software renderer.

Take a look at /system/lib/egl/egl.cfg In many cases where I've looked (though it varies on device) the software renderer does get picked up. If you remove the entry for the software renderer, it often speeds up in general, because hardware is forced to be used.

Linaro doubles performance for Android ICS

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