[sirn]

Was your emulation done with qemu user space emulator[1] (the syscall translation layer) or qemu system emulator[2] (the VM)? If it was qemu-system you might have better numbers with qemu-user-static, which does binary translation similar to Rosetta 2 rather than a being a full system emulator with all its overhead.

You can probably use qemu-user-static to translate x86-64-only binaries in a Linux container on an ARM machine, too, but I have never tried.

[1]: https://www.qemu.org/docs/master/user/main.html

[2]: https://www.qemu.org/docs/master/system/index.html

[bmalehorn]

I ran this on a Linux laptop - it looks like it's running qemu-user-static:

    root        9934  103  0.0 125444  6664 pts/0    Rl+  12:25   0:12 /usr/bin/qemu-aarch64-static /usr/bin/gzip

So it might be that Docker already runs a native x86_64 Linux, then uses qemu-static binary translation.

[sirn]

That's strange, in my experience it shouldn't have 6x slowdown. Probably might be due to several factors, but here's your test, running on my system without Docker:

Ryzen 3900X (host machine)

    $ dd if=/dev/urandom bs=4k count=10k | gzip >/dev/null
    10240+0 records in
    10240+0 records out
    41943040 bytes (42 MB, 40 MiB) copied, 1.02284 s, 41.0 MB/s

qemu-aarch64-static

    $ dd if=/dev/urandom bs=4k count=10k | proot -R /tmp/aarch64-alpine -q qemu-aarch64-static sh -c 'gzip >/dev/null'
    10240+0 records in
    10240+0 records out
    41943040 bytes (42 MB, 40 MiB) copied, 3.33964 s, 12.6 MB/s