Qualcomm Employee: 64-Bit A7 Chip 'Hit Us In The Gut'

[Truffy]

It's a stunning chip, great for Apple customers!

In what way? I have a iPhone 5s, so I'm not being antagonistic, but if the remainder of the architecture and apps cannot make use of 64-bit now, what's the point. Except bragging rights, and that's too sad.

 

[yeah]

Only for applications that are are being bottlenecked by 32-bit architecture, which are rare.

The best way to explain it is that jumping from 32 to 64-bit doesn't offer any performance gains in and of itself, but it's less likely to get bogged down, because it can handle larger amounts of data being thrown at it more gracefully. Like if you have a game that's been compiled for both architectures, the 64-bit version won't have double the framerate of it's 32-bit counterpart. But if you were to start throwing in complex physics models, and higher end AI, a 64-bit processor running the same amount of cores on the same CPU architecture as a 32-bit processor would be able to leverage all that information a little better, leading to slightly improved framerates.

It wouldn't be a massive, game changing, difference, but it'd be measurable. Thought that advantage could be matched by a slightly quicker 32-bit processor. Really, the best places to see the real advantages in 64-bit architecture would be in movie editing with large files, 3D rendering, and the like. Anything that has to do with tons of raw data being tossed around and worked on. Things you're not currently doing on iOS, in other words.

Do you think a 64-bit email app will allow you to type out words faster? Will it send your messages any quicker? What about 64-bit Angry Birds? Will it allow for...what...more birds onscreen? Will it suddenly be better because you can stuff twice the amount of data into a 64-bit register? Hell, these apps aren't even coming close to saturating a 32-bit chip. 64-bit won't do anything.

Anyway, the A7 chip is ~2X faster than the A6 already and 64-bit apps will receive slight performance gains to major performance gains, depending on the app.

 

[osofast240sx]

In what way? I have a iPhone 5s, so I'm not being antagonistic, but if the remainder of the architecture and apps cannot make use of 64-bit now, what's the point. Except bragging rights, and that's too sad.

But there is an improvement. Do a search there is plenty of info on the improvements of 64bot architecture.

 

[throttlemeister]

You are outing yourself here. AArch64 (the 64 bit ARM architecture) uses less power. The instruction set has been simplified. Twenty years of experience of what works well and what doesn't in the 16 and 32 bit instruction set lead to changes that improve the operation of the processor.

You're outing yourself, as you are not reading. He specifically mentioned "of the same caliber", as in apples to apples instead of apples to oranges what would be the case when comparing to different generations as you do.

The 64-bit A7 will be more power hungry than a hypothetical 32-bit A7.

It's like most people in this thread are saying the 64-bit A7 is faster than the 32-bit A6, ergo 64-bit is faster than 32-bit. No. The A7 is faster than the A6.

----------

But there is an improvement. Do a search there is plenty of info on the improvements of 64bot architecture.

There is improvement in some areas. There downsides in other areas as well. Increased address space increases the risk of dirty cache, which can have a rather significant negative impact on performance.

 

[tdream]

No source, no credibility. Fishing for news as per usual.

 

[n-evo]

I upgraded from an iPhone 5 to iPhone 5S and notice on a daily basis how much buggier iOS 7 64-bit is. I have weird interface quirks in places the iPhone 5 had none. Certain apps, like Camera app, won't save settings anymore. It's annoying.

 

[thekeyring]

When are people going to get that moving to 64-bit improves performance regardless of how much RAM the device has?

When Samsung does it, without upping their ram.

 

[Razeus]

Now, if only can Apple do something about my iPhone 5S randomly rebooting.

 

[kdarling]

Other companies still have to wait for Google to update Android to 64-bit. They're at Google's mercy.

More like they don't have to spend all that R&D themselves.

That's what happens when you rely on other companies to provide your software. There's no point in putting 64-bit hardware in phones until Google's 64-bit software is ready.

That's like saying there's no point in putting in a 64 bit CPU in an iPhone until all the available apps are recompiled. Yet everyone is claiming there's a benefit just by having the CPU.

With Android, each manufacturer could start with recompiling the kernel and drivers for 64 bit. That's easy enough.

After that, the big advantage is that almost all Android apps are Java based. That means if the runtime gets recompiled and tweaked, ALL the apps immediately benefit... no recompile necessary by the hundreds of thousands of developers.

 

[Tiger8]

Safari SUCKS!

Still think 64 bit is stupid. My iPad Air can't keep more than 1.5 tabs loaded at a time. It is actually worse than the iPad 3 and iPhone 5 in Safari. Whatever performance benefits there are are outweighed by the pointless extra ram usage.

Does it seem worse at a few things than the old iPad to anyone else? I notice that it can keep less iPad Safari tabs open without needing to reload. I also see more crashes, even on native apps.

It might not be the chip, for years I exclusively used Safari on all iDevices, but last year I downloaded another browser, and believe it or not, it is incredibly faster and smoother using iOS7.... on my (get this) iPad 3! Safari seems to hang, completely FREEZE while loading pages, I am very disappointed in it.

 

[thekeyring]

Apple switched to 64bit ARM, because it's the future. Software like iOS may seen not quite ready at the moment, benefits are blurry, but being already there gives them big advantage over competition. They ARE THERE, and now they can focus on fixing all the bugs and maxing out the benefits.

Thank you!! And within a few years all the iPhones they sell will have 64 bit processors. How long before 32 bit android phones stop selling? More fragmentation.

 

[MikhailT]

what's weird to me is that apple's chips are made by samsung, so two of the biggest phone manufacturers are privvy to Apple's 64-bit plan. Qualcomm must've been really blind-sighted to not see where the industry is going.

Technically, only Samsung's fab division is supposed to know about Apple's designs due to heavy confidential information protected by contracts, laws, and so on.

The rest of Samsung aren't supposed to know anything, they are supposed to keep each division isolated or they'd risk losing a lot of money because beside losing Apple, they'll lose a lot of customers who will not use their fabs in order to protect their IPs.

There were news last year that Samsung made this clear to everybody, that their foundry division is fire-walled from their devices division.

why would Google do this for andriod when they are moving to chrome OS.

Which would pretty much destroy all of the anti-fragmentation work they've been working on and it'd likely to destroy any chances of getting more developers over to their side.

The Android market is already a mess with a lot of developers having a tough time maintaining the same app code for several Android releases as the market don't upgrade quickly enough.

If Google switches to ChromeOS, that's just going to hurt them even more.

Considering the low market share of Chrome OS and the fact that Samsung pretty much have the Android market locked up, Google's going to have a huge problem on their hands if they try to switch to ChromeOS for mobile devices. Their Chromebooks aren't really a huge success either for now.

 

[GenesisST]

Pretty sure Qualcomm will catch up eventually. Intel did catch up to AMD on the 64-bit front after all. Apple did catch up to Blackberry (euphemism...), Android did catch up to Apple, ad nauseam..

Just competition at work, which is good!

 

[Max(IT)]

How often do we see similar reports in the press?

1. Apple releases a new product.
2. Competitors gripe that it's a worthless upgrade.
3. Apple sells tons of devices.
4. Competitors rush to make their devices like Apple's.

It's always the same ... Now wait for the brand new "Samesung Galaxy S5/6/7" with 64-bit architecture but a 3 Ghz CPU, 8 Gb ram and a 56" display

 

[jellomizer]

When are people going to get that moving to 64-bit improves performance regardless of how much RAM the device has?

Because for the most part it doesn't.

Unless you are dealing with big numbers over 4 billion, The performance gains from the chip is often loss to the Slower Bus having to read in 64 bit commands vs 32 bit commands.

Now if you device can use more RAM, that the 64 bit system can address then you get the performance back.

 

[gotluck]

When Samsung does it, without upping their ram.

Haha, funny aside from the fact the note 3 is already maxing out on 32bit with 3gigs of ram.

 

[osofast240sx]

Technically, only Samsung's fab division is supposed to know about Apple's designs due to heavy confidential information protected by contracts, laws, and so on.

The rest of Samsung aren't supposed to know anything, they are supposed to keep each division isolated or they'd risk losing a lot of money because beside losing Apple, they'll lose a lot of customers who will not use their fabs in order to protect their IPs.

There were news last year that Samsung made this clear to everybody, that their foundry division is fire-walled from their devices division.



Which would pretty much destroy all of the anti-fragmentation work they've been working on and it'd likely to destroy any chances of getting more developers over to their side.

The Android market is already a mess with a lot of developers having a tough time maintaining the same app code for several Android releases as the market don't upgrade quickly enough.

If Google switches to ChromeOS, that's just going to hurt them even more.

Considering the low market share of Chrome OS and the fact that Samsung pretty much have the Android market locked up, Google's going to have a huge problem on their hands if they try to switch to ChromeOS for mobile devices. Their Chromebooks aren't really a huge success either for now.

Samsung is due to launch a flagship phone on a Tizen os in 2014. Do you think Samsung is going to have the same issues

 

[LordVic]

Not how I prefer it. No upgrades and only Apple replacements if they get to control their whole desktop PC side. But if they ever do that, the future Mac users can read my signature and weep VVV

you mean, exactly like they're trying with the new Mac Pro that doesn't use a single "off the shelf part" and can only use specific parts made exclusively for the new fart tube.

ther'es a reason why Apple likes this idea of Appliance computers. If you haven't noticed they've moved virtually their entire product line, including x86 based computers to almost entirely proprietary hardware. From MacBook Airs, Pro's, iMacs, Mini's and new Mac pro, they're almost all, top to bottom. proprietary.

if you go look at any of the New Mac Pro threads here, or in the Mac Pro sub forum you'll see a LOT of people weeping.

 

[xofruitcake]

In what way? I have a iPhone 5s, so I'm not being antagonistic, but if the remainder of the architecture and apps cannot make use of 64-bit now, what's the point. Except bragging rights, and that's too sad.

Because you do not read enough to know what you are talking about does not make your argument right. This is what Anandtech said about the A7. Notice the timing issue for 2015/2016 software and the increase in both number and size of the general purpose register and floating point registers. There are a lot of reasons why it is important to have 64 bits processor now aside from all the other improvement that come with the A7 redesign.

http://www.anandtech.com/show/7335/the-iphone-5s-review/3

The move to ARMv8 comes with some of its own performance enhancements. More registers, a cleaner ISA, improved SIMD extensions/performance as well as cryptographic acceleration are all on the menu for the new core.

Pipeline depth likely remains similar (maybe slightly longer) as frequencies haven’t gone up at all (1.3GHz). The A7 doesn’t feature support for any thermal driven CPU (or GPU) frequency boost.

The most visible change to Apple’s first ARMv8 core is a doubling of the L1 cache size: from 32KB/32KB (instruction/data) to 64KB/64KB. Along with this larger L1 cache comes an increase in access latency (from 2 clocks to 3 clocks from what I can tell), but the increase in hit rate likely makes up for the added latency. Such large L1 caches are quite common with AMD architectures, but unheard of in ultra mobile cores. A larger L1 cache will do a good job keeping the machine fed, implying a larger/more capable core.

The A7’s memory controller sees big improvements as well. I measured 20% lower main memory latency on the A7 compared to the A6. Branch prediction and memory prefetchers are both significantly better on the A7.

I noticed large increases in peak memory bandwidth on top of all of this. I used a combination of custom tools as well as publicly available benchmarks to confirm all of this. A quick look at Geekbench 3 (prior to the ARMv8 patch) gives a conservative estimate of memory bandwidth improvements:


We see anywhere from a 6% improvement in memory bandwidth to nearly 60% running the same Stream code. I’m not entirely sure how Geekbench implemented Stream and whether or not we’re actually testing other execution paths in addition to (or instead of) memory bandwidth. One custom piece of code I used to measure memory bandwidth showed nearly a 2x increase in peak bandwidth. That may be overstating things a bit, but needless to say this new architecture has a vastly improved cache and memory interface.

The more I think about it, the more the timing actually makes a lot of sense. The latest Xcode beta and LLVM compiler are both ARMv8 aware. Presumably all apps built starting with the official iOS 7 release and going forward could be built 64-bit aware. By the time 2015/2016 rolls around and Apple starts bumping into 32-bit addressability concerns, not only will it have navigated the OS transition but a huge number of apps will already be built for 64-bit. Apple tends to do well with these sorts of transitions, so starting early like this isn’t unusual. The rest of the ARM ecosystem is expected to begin moving to ARMv8 next year.

Apple isn’t very focused on delivering a larger memory address space today however. As A64 is a brand new ISA, there are other benefits that come along with the move. Similar to the x86-64 transition, the move to A64 comes with an increase in the number of general purpose registers. ARMv7 had 15 general purpose registers (and 1 register for the program counter), while ARMv8/A64 now has 31 that are each 64-bits wide. All 31 registers are accessible at all times. Increasing the number of architectural registers decreases register pressure and can directly impact performance. The doubling of the register space with x86-64 was responsible for up to a 10% increase in performance.

The original ARM architecture made all instructions conditional, which had a huge impact on the instruction space. The number of conditional instructions is far more limited in ARMv8/A64.

The move to ARMv8 also doubles the number of FP/NEON registers (from 16 to 32) as well as widens all of them registers to 128-bits (up from 64-bits). Support for 128-bit registers can go a long way in improving SIMD performance. Whereas simply doubling register count can provide moderate increases in performance, doubling the size of each register can be far more significant given the right workload. There are also new advanced SIMD instructions that are a part of ARMv8. Double precision SIMD FP math is now supported among other things

 

[skinned66]

This is what Apple does well - push new tech and force change; and everyone should be thankful for it because in the end it's good for everyone.

 

[coolspot18]

I find it pretty amazing that someone would so willingly overlook a huge advancement like this.

There are benefits, in the future, but its pointless advertising a feature that can't be leveraged currently.

It's like me selling you a hyperspace communicator, who are you gonna call?

 

[mabhatter]

The A7 is a power house but imho 64-bit is useless with 1GB Ram.

Apple's 64-bit available instruction set is more efficient. They opted to put it out now, while its just "slightly better" so that they have time to really make it super good and get apps moved over.

I think its a setup to use the A-series chips in other devices... Like that 13" iPad or MacBook Air replacement. Apple is designing "two steps" ahead even if it doesn't make sense now to "over design".

Remember the switch to Intel wasn't "we'll get around to it". The switch to Intel was one keynote... "And by the way" ... This whole presentation was on the new hardware and OS... Pick up your new computers in the fall.

 

[iSunrise]

Still think 64 bit is stupid. My iPad Air can't keep more than 1.5 tabs loaded at a time. It is actually worse than the iPad 3 and iPhone 5 in Safari. Whatever performance benefits there are are outweighed by the pointless extra ram usage.

One of the very reasons why I am happy that I didn´t buy the Air. On the 5s this is OK, because it has only about 1/4 of the resolution. Seems the higher memory footprint really will bite the Air in the ass. And for a tablet that´s supposed to last at least 2-3 years, this is a no-go.

Still happy with my iPad 3 and glad I didn´t sell it.

 

[HurtinMinorKey]

So PREDICTABLE.

It's already been established that there are more benefits to a 64-bit architecture than an increase in RAM capacity.

No, I don't care to elaborate. You can search ANY thread that mentions "64-bit".

It's not that simple. There are also some drawbacks. If your apps don't need 32 bits, then going to 64 is effectively having the cache size.

So it can be detrimental to performance as well.

 

[mabhatter]

In what way? I have a iPhone 5s, so I'm not being antagonistic, but if the remainder of the architecture and apps cannot make use of 64-bit now, what's the point. Except bragging rights, and that's too sad.

Apple has to start somewhere. Devs cannot compile 64bit programs until 64bit hardware is sold. A7 with 64 bit, is "better" than A6. Sure Apple "could have" made A7 be more faster at 32 bits and left out 64 bits... But your new phone is strictly much faster than the old one so why do you care? You pay for APPS to run and do stuff you want. not 32 or 64 bits ... This isn't PC land where stuff is endlessly debated. Apple just does what they want, and we follow or don't.