Why is Rosetta 2 fast?

Post by kijiki » Wed, Nov 09, 2022, 7:25 PM UTC

nicoburns wrote: post #30

menaerus wrote: post #14

> Rosetta 2 translates the entire text segment of the binary from x86 to ARM up-front. Do I understand correctly that the Rosetta is basically a transpiler from x86-64 machine code to ARM machine code which is run prior to the binary execution? If so, does it affect the application startup times?

> If so, does it affect the application startup times? It does, but only the very first time you run the application. The result of the transpilation is cached so it doesn't have to be computed again until the app is updated.

Post by my123 » Wed, Nov 09, 2022, 7:29 PM UTC

Symmetry wrote: post #109

jrmg wrote: post #55

Earlier quoted context omitted.

Apple reportedly has already ported many of it's secondary cores to RISC-V Really? In current hardware or is this speculation?

If you've got some management core somewhere in your silicon you can, with RISC-V, give it a MMU but no FPU and save area. You're going to be writing custom embedded code anyways so you get to save silicon by only incorporating the features that you need instead of having to meet the full ARM spec. And you can add your own custom instructions for the job at hand pretty easily. That would all be a terrible idea if you…

Post by saagarjha » Wed, Nov 09, 2022, 7:30 PM UTC

titzer wrote: post #89

Rosetta 2 is great, except it apparently can't run statically-linked (non-PIC) binaries. I am unsure why this limitation exists, but it's pretty annoying because Virgil x86-64-binaries cannot run under Rosetta 2, which means I resort to running on the JVM on my M1...

  $ file a.out
  a.out: Mach-O 64-but executable x86_64
  $ tool -L a.out
  a.out:
  $ ./a.out
  Hello, world!

Post by saagarjha » Wed, Nov 09, 2022, 7:33 PM UTC

agentcooper wrote: post #49

I am interested in this domain, but lacking knowledge to fully understand the post. Any recommendations on good books/courses/tutorials related to low level programming?

Post by Vt71fcAqt7 » Wed, Nov 09, 2022, 7:34 PM UTC

chris_j wrote: post #62

Vt71fcAqt7 wrote: post #38

Earlier quoted context omitted.

>That's not going to happen unless Apple decides to switch from ARM to RISC-V, and... why would they? They've got 15 years experience and essentially full control on ARM. Two points here. • First off, Apple developers are not binded to Apple. The knkwledge gained can be used elsewhere. See Rivos and Nuvia for example. • Second, Apple reportedly has already ported many of it's secondary cores to RISC-V. It's not unrea…

For me, those two points make it clear that it would be possible for Apple to port to RISC-V. But it's still not clear what advantages they would gain from doing so, given that their ARM license appears to let them do whatever they want with CPUs that they design themselves.