Google wants RISC-V to be a "tier-1" Android architecture

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Over the holidays, footage from the recent "RISC-V Summit" was released for the world to see, and would you believe Google showed up to profess its love for the next generation CPU architecture?

We've been trying to figure out what the Android team thinks about RISC-V (reduced instruction set computer) for a while. We last heard a comment from the team six months ago, where our Google I/O question on RISC-V was only answered with "we're looking at it, but this would be a big change for us" . Some external RISC-V porting projects exist, and various RISC-V commits have landed in the Android Open Source Project (AOSP), but since anyone can submit code to AOSP, it's been difficult to make bold claims. on RISC-V. Android status.

Google's keynote at the RISC-V summit, however, was all about bold claims. Lars Bergstrom, director of engineering at Android, wants RISC-V to be considered a "platform tier 1" in Android, which would put it on par with Arm. This is a big change from just six months ago. Bergstrom says getting optimized builds of Android on RISC-V will take "a lot of work" and outlined a roadmap that will take "a few years" to materialize, but AOSP has started landing official RISC-V patches. V in September. /p>

The build system is up and running, and anyone can grab the latest "riscv64" branch whenever they want - and yes, consistent with their recent Arm work, Google wants RISC-V on Android to be 64 only bits. For now, all you can get is a command line, and Bergstrom's slide promised "initial emulator support by early 2023, with Android RunTime support (ART) for Java workloads in Q1".

Enlarge / RISC-V on Android will be a long journey. Lars Bergstrom

One of Bergstrom's slides showed the above "to do" list, which included a ton of major Android components. Unlike Android's unpolished support for x86, Bergstrom promised a real push for quality with RISC-V, saying, "We have to do all the hard work to get from a prototype and something that works to something that really sings - that shows the best - of the class processors that [RISC-V International President Krste Asanović] mentioned in the previous talk."

Once Google installs Android on RISC-V, it will be up to manufacturers and the app ecosystem to support the platform. The fun thing about Android RunTime is that when ART supports RISC-V, so much of the Android app ecosystem will come with it. Android apps are delivered as Java code, and the way it becomes an ARM app is when the Android runtime compiles it into ARM code. Instead, it will soon be compiled to RISC-V code with no additional work from the developer. Native code that is not written in Java, such as games and component libraries, will need to be ported, but starting with Java code is a big step forward.

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