Re:About the Rosetta Translation Environment
by jojobas on Tuesday June 23, 2020 @11:22AM
(#23615089)
My gut feeling is that it will be about the same as Itanium/HP Envy x2 emulation. Emulation of highly optimized hardware where code is generated by highly optimized compilers without an order of magnitude slowdown is just too good to be true.
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Re:About the Rosetta Translation Environment
by hedora on Tuesday June 23, 2020 @08:34PM
(#23622410)
Valgrind does something similar (x86->intermediate language->x86), and is only about 4x slower than native with all the analyses disabled. I’d guess they left some optimizations out to make it easier to implement the dynamic checks it supports.
Re:About the Rosetta Translation Environment
by jojobas on Tuesday June 23, 2020 @09:08PM
(#23622706)
Valgrind leaves most instructions as they were doesn't it? If you're not touching the dynamic memory it should be as fast. You wouldn't be able to do that with complex MMX or SSE2 instructions with Arm translation.
Re:About the Rosetta Translation Environment
by hedora on Wednesday June 24, 2020 @03:33PM
(#23632788)
It lifts them to a simplified version of x86 so they can be instrumented / transformed more easily. I think that implies you get different instructions when it lowers back to x86, but I could be wrong. (I’ve written a specialized valgrind instrumentation tool or two, but didn’t look too carefully at the execution half of their codebase.)