[Docker Desktop for Mac] - Running i386 binaries have poor performance with qemu-i386

[hawie]

Tell us about your request Is it possible to use Rosetta2 qemu-x64-to-i386 instead?

Which service(s) is this request for? Docker Desktop for Mac

Tell us about the problem you're trying to solve. What are you trying to do, and why is it hard? Ensure that users can run their i386 based workloads on Apple Silicon, taking advantage of Rosetta2's 64-bit high performance.

Are you currently working around the issue? docker: /usr/bin/qemu-i386 performs poorly, /run/rosetta/rosetta is very fast. Win11Arm on macOS: i386 apps are fast. From what Windows 11 does, we can see that Apple sillion can run i386 programs faster, much faster than qemu-i386. So similarly, is it possible to generate a version, an x64 version of qemu executed by Rosetta2, providing x32(i386) translation?

[hawie]

Can you give an approximate time, and in what future version is this feature expected to be added? Notice that the new v4.34.3 has not yet added this feature.

[KatTomrushka]

Thank you for suggesting using Rosetta 2 for faster i386 emulation in Docker Desktop for Mac!

After evaluation, we won't be implementing this feature because:

1. Most containerized workloads have moved to 64-bit, with many Linux distributions dropping 32-bit support
2. The engineering effort would be substantial for a limited use case

We recommend migrating i386 workloads to 64-bit where possible, which aligns with industry direction and would benefit from better performance on Apple Silicon. We're focusing our resources on Docker VMM and the Apple Virtualization Framework, which provide better native performance for modern workloads on Apple Silicon. It's also worth noting that Rosetta 2 is proprietary Apple technology, and implementing i386 support within it would require work from Apple, who are similarly focused on supporting modern 64-bit workloads.

I appreciate your technical insight and have shared your observations with our engineering team.