64bit iOS7

9 replies [Last post]
syrupcore
Offline
Joined: 09/26/2010

Word on the street re: music apps is "meh, no big deal". Then there were some comments at Discchord from developers that said the only apps that will see a performance increase are apps that use significant amounts of Assembly code. I know NS1 does.

Matt, do you think we will see a performance boost in NS1 from the 32->64bit change? How about in NS2/Whatever-youre-calling-it-these-days? I also notice that it will include OpenGL 3. Same questions there. I understand if this is speculation without actually having a new device with the new OS but I'm curious.

Blip Interactive
Offline
Joined: 04/05/2010

Hasn't 64 bit always been a massive meh for nearly everything aside from servers and number crunching? The extra cache misses often seem to the outweigh processing gains. 32 bits is actually pretty good for storing most 'real world' values at most 'real world' accuracies, so the move from 32->64 bits is much less effective than the move from 16->32 was.

It's funny how the old 'larger addressable area of RAM' thing gets mentioned along with 64 bit - yes, 64 bit processors can generally address a larger area of RAM than their 32 bit counterparts but that's often not the main point.

More important for the 64 bit ARMv8 is that it has a double sized register file for SIMD. This could definitely be useful for realtime audio work, although with users now expecting lower latencies and using small buffer sizes then it's starting to get to the stage where the set up cost of a SIMD routine and all the registers it needs becomes significant compared to the time spent actually running the DSP. More registers will always be good for FIR, convolution, image processing etc. though.

Most annoying of all is that they have removed some instructions and changed others in the 64 bit ARM instruction set. This will require maintaining two versions of every assembler routine - not sure I want to go there right now for an overall 20% speed up (that figure's a total guess!).

instinctive
Offline
Joined: 07/23/2011

Now that OpenGL is mentioned... wouldn't it be an interesting idea trying to abuse the GPU to do Audio work? :)

syrupcore
Offline
Joined: 09/26/2010

Back to 'meh' it is then. :) Thanks for the reply.

Galaxyexplorer (not verified)

Yes.... meh, meeeehhhh!
(...but still waiting for the ram info on the A7...)

Galaxyexplorer (not verified)

O.k... there are the first 64bit optimized music apps out. "djay2" and "vjay". Perhaps not "real" music production apps but i have them too on my iPhone 5 and will see how it will works on my new device (when it arrives). However there are some 5s only extras etc. So perhaps it's not a meehhhhhh ;)

syrupcore
Offline
Joined: 09/26/2010

I bailed half way through but potentially interesting technical write up on the arm64 in the new phones (and presumably ipads)

ARM64 and You
http://www.mikeash.com/pyblog/friday-qa-2013-09-27-arm64-and-you.html

dendy
Offline
Joined: 07/28/2010

regarding 64bit A7.. here are few words from Tempo Rubato's twitter:

"We have twice the number of floating point registers in the A7. Also a much better floating point instruction set. Great for audio DSP!"

btw. the power of new A7 chip is really impressive.. i bought iPAd Air yesteday.. after few first tests in Auria, it is REALLY powerfull.. LOT of quality plugins and still only at 50% of cpu load :)

Hope NS2 will be able fully utilise the power of new chip :-))

Slam-Cut
Offline
Joined: 09/07/2011

dendy: Thanks for sharing your iPad Air tests. Has iOS7 had any issues for you, especially regarding music production?

dendy
Offline
Joined: 07/28/2010

i have 7.0.3 and no issues...

btw regarding auria, i loaded 32 tracks, all with channel strip turned on, convolution reverb + psp stereo delay on sends and 20 instances of FabFilter PRO-Q with 4 bands turned on - and i got 76% of cpu load, gui only slightly slowed, playback without dropouts... damn i remember times when i was producing on desktop which hat lot less power than A7 chip :-))))