5 ms·

For people who know more about this stuff than me: are these sorts optimizations only possible because Apple controls the whole stack and can make the hardware

For people who know more about this stuff than me: are these sorts optimizations only possible because Apple controls the whole stack and can make the hardware & OS/software perfectly match up with one another or is this something that Intel can do but doesn't for some reasons (tradeoffs)?

deleted 6y ago
[deleted]
wmf 6y ago
No, there's no cross-stack optimization here. The M1 gives very high performance for all code.
- qeternity 6y ago
  I think this gets lost in the fray between the "omg this is magic" and then the Apple haters. The M1 is a very good chip. Apple has hired an amazing team and resourced them well. But from a pure hardware perspective, the M1 is quite evolutionary. However the whole Apple Silicon experience is revolutionary and magical due to the tight software pairing. Both teams deserve huge praise for the tight coordination and unreal execution.
  - acdha 6y ago
    I think this is part of the reason where there are so many people trying to find reasons to downplay it: humans love the idea of “one weird trick” which makes a huge difference and we sometimes find those in tech but rarely for mature fields like CPU design. For many people, this is unsatisfying like asking an athlete their secret, and getting a response like “eat well, train a lot, don't give up” with nary a shortcut in sight.
AnthonyMouse 6y ago
> are these sorts optimizations only possible because Apple controls the whole stack and can make the hardware & OS/software perfectly match up with one another or is this something that Intel can do but doesn't for some reasons (tradeoffs)? Interestingly it's the other way around. Apple is using TSMC's 5nm process (they don't have their own fabs), which is better than Intel's in-house fabs, so it's Intel's vertical integration which is hurting them compared to the non-vertically integrated Apple. Also, the answer to "is this only possible because of vertical integration" is always no. Intel and Microsoft regularly coordinate to make hardware and software work together. Intel is one of the largest contributors to the Linux kernel, even though they don't "own" it. Two companies coordinating with one another can do anything they could do as an individual company. Sometimes the efficiency of this is lower because there are communication barriers and isn't a single chain of command. But sometimes it's higher because you don't have internal politics screwing everything up when the designers would be happy with outsourcing to TSMC because they have a competitive advantage, but the common CEO knows that would enrich a competitor and trash their internal investment in their own fabs, and forces the decision that leads to less competitive products.
- cma 6y ago
  Not quite vertical integration, but TSMC's 5nm fabs are Apple's fabs. (exclusively for a period of time) During the iPod era, Toshiba's 1.8in HD production was exclusively Apple's only for music players, but Apple gets all the 5nm output from TSMC for a period of time.
- hinkley 6y ago
  Integration is a petri dish. It can speed up both growth and decay, and it is indifferent to which one wins.
deleted 6y ago
[deleted]
viktorcode 6y ago
There's at least two M1 optimisations targeting Apple's software stack: 1. Fast uncontended atomics. Speeds up reference counting which is used heavily by Objective-C code base (and Swift). Increase is massive comparing to Intel. 2. Guaranteed instruction ordering mode. Allows for faster Arm code to be produced by Rosetta when emulating x86. Without it emulation overhead would be much bigger (similar to what Microsoft is experiencing).
alblue 6y ago
Sort of; Intel and AMD are stuck with the variable width instruction isa that exists due to historical evolution. To do something different you need a new isa. Intel tried this with Itanium a while back and failed because it is difficult to get software developers to target a new isa and provide compilers and compiled code for everything unless you use a translation layer. Apple is one step ahead here because their compilers already supported ARM isa (because iPhones use them) and had both the OS and apps ready to go from day one of availability. They also had translation technology that would allow mutating x86_64 code to ARM64 code so that old apps would (on the whole) run acceptably fast on the new chip. To do the latter properly, Apple had to create a special mode to run the arm chip with total store order for memory writes, which is not standard on arm. (It would be a lot slower if they didn’t have that when running Rosetta translated code.) So both the OS being available, and the OS influencing the ARM tweaks (eg TSO) could they pull it off. They also have the position that they build hardware that uses those chips so can mass produce - and in fact, replace - existing hardware. Each of these things could be done in isolation by Intel/Windows/Apps but it would be difficult to do all three. Even getting JavaScript maths in a special instruction was difficult enough on Intel, and that was something of benefit to any browser. My guess is you’ll see Intel and AMD offering Arm chips in the near future, as both AWS (graviton) and Apple have shown the way to a new ARM future.
- pjmlp 6y ago
  Intel only failed, because AMD exists and had a license to produce x86 based CPUs. Without AMD everyone would eventually be dragged into adopting Itanium.

deleted 6y ago

[deleted]

wmf 6y ago

No, there's no cross-stack optimization here. The M1 gives very high performance for all code.

qeternity 6y ago
I think this gets lost in the fray between the "omg this is magic" and then the Apple haters. The M1 is a very good chip. Apple has hired an amazing team and resourced them well. But from a pure hardware perspective, the M1 is quite evolutionary. However the whole Apple Silicon experience is revolutionary and magical due to the tight software pairing. Both teams deserve huge praise for the tight coordination and unreal execution.
- acdha 6y ago
  I think this is part of the reason where there are so many people trying to find reasons to downplay it: humans love the idea of “one weird trick” which makes a huge difference and we sometimes find those in tech but rarely for mature fields like CPU design. For many people, this is unsatisfying like asking an athlete their secret, and getting a response like “eat well, train a lot, don't give up” with nary a shortcut in sight.

AnthonyMouse 6y ago

> are these sorts optimizations only possible because Apple controls the whole stack and can make the hardware & OS/software perfectly match up with one another or is this something that Intel can do but doesn't for some reasons (tradeoffs)? Interestingly it's the other way around. Apple is using TSMC's 5nm process (they don't have their own fabs), which is better than Intel's in-house fabs, so it's Intel's vertical integration which is hurting them compared to the non-vertically integrated Apple. Also, the answer to "is this only possible because of vertical integration" is always no. Intel and Microsoft regularly coordinate to make hardware and software work together. Intel is one of the largest contributors to the Linux kernel, even though they don't "own" it. Two companies coordinating with one another can do anything they could do as an individual company. Sometimes the efficiency of this is lower because there are communication barriers and isn't a single chain of command. But sometimes it's higher because you don't have internal politics screwing everything up when the designers would be happy with outsourcing to TSMC because they have a competitive advantage, but the common CEO knows that would enrich a competitor and trash their internal investment in their own fabs, and forces the decision that leads to less competitive products.

cma 6y ago
Not quite vertical integration, but TSMC's 5nm fabs are Apple's fabs. (exclusively for a period of time) During the iPod era, Toshiba's 1.8in HD production was exclusively Apple's only for music players, but Apple gets all the 5nm output from TSMC for a period of time.
hinkley 6y ago
Integration is a petri dish. It can speed up both growth and decay, and it is indifferent to which one wins.

deleted 6y ago

[deleted]

viktorcode 6y ago

There's at least two M1 optimisations targeting Apple's software stack: 1. Fast uncontended atomics. Speeds up reference counting which is used heavily by Objective-C code base (and Swift). Increase is massive comparing to Intel. 2. Guaranteed instruction ordering mode. Allows for faster Arm code to be produced by Rosetta when emulating x86. Without it emulation overhead would be much bigger (similar to what Microsoft is experiencing).

alblue 6y ago

Sort of; Intel and AMD are stuck with the variable width instruction isa that exists due to historical evolution. To do something different you need a new isa. Intel tried this with Itanium a while back and failed because it is difficult to get software developers to target a new isa and provide compilers and compiled code for everything unless you use a translation layer. Apple is one step ahead here because their compilers already supported ARM isa (because iPhones use them) and had both the OS and apps ready to go from day one of availability. They also had translation technology that would allow mutating x86_64 code to ARM64 code so that old apps would (on the whole) run acceptably fast on the new chip. To do the latter properly, Apple had to create a special mode to run the arm chip with total store order for memory writes, which is not standard on arm. (It would be a lot slower if they didn’t have that when running Rosetta translated code.) So both the OS being available, and the OS influencing the ARM tweaks (eg TSO) could they pull it off. They also have the position that they build hardware that uses those chips so can mass produce - and in fact, replace - existing hardware. Each of these things could be done in isolation by Intel/Windows/Apps but it would be difficult to do all three. Even getting JavaScript maths in a special instruction was difficult enough on Intel, and that was something of benefit to any browser. My guess is you’ll see Intel and AMD offering Arm chips in the near future, as both AWS (graviton) and Apple have shown the way to a new ARM future.

pjmlp 6y ago
Intel only failed, because AMD exists and had a license to produce x86 based CPUs. Without AMD everyone would eventually be dragged into adopting Itanium.