benhoyt

To me, the most interesting change is the performance improvement due to the new register-based calling convention. Your CPU-bound programs will magically get 5% faster when compiled with 1.17:

> Go 1.17 implements a new way of passing function arguments and results using registers instead of the stack. Benchmarks for a representative set of Go packages and programs show performance improvements of about 5%, and a typical reduction in binary size of about 2%. This is currently enabled for Linux, macOS, and Windows on the 64-bit x86 architecture (the linux/amd64, darwin/amd64, and windows/amd64 ports).

I love how they're doing it in such an iterative fashion: even assembly functions don't have to be rewritten. Then again, I guess doing it progressively like this is the only feasible way to avoid reworking all the low-level assembly routines in one fell swoop.

benhoyt
Wow, this update is awesome: my GoAWK interpreter (https://github.com/benhoyt/goawk) runs a simple CPU-bound AWK program 38% faster when compiled with Go 1.17 (compared to 1.16).

  $ time goawk_go1.16 'BEGIN { for (i=0; i<100000000; i++) s += i; print(s) }'
  4999999950000000
  real    0m10.158s ...
  $ time goawk_go1.17 'BEGIN { for (i=0; i<100000000; i++) s += i; print(s) }'
  4999999950000000
  real    0m6.268s ...
I wonder why it's so much better than their advertised 5% perf improvement? Here's a quick CPU profile: https://i.imgur.com/csJyOYq.png ... I don't get too much out of it at a glance, just seems like everything's a bunch faster.