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Performance

go-ruby-time/time is the pure-Go library that rbgo binds for Ruby's time. This page records a comparative benchmark of that module against the reference Ruby runtimes, part of the ecosystem-wide per-module parity suite.

What is measured

The same Ruby script — the same workload — constructing an instant and formatting it through strftime / iso8601 / rfc2822 plus a Time.parse round-trip — is run under every runtime. rbgo's number reflects this pure-Go library doing the work; every other column is that interpreter's own time implementation. So the comparison is the Ruby-visible operation, apples-to-apples across interpreters. The script prints a deterministic checksum and its output is checked byte-identical to MRI before timing.

  • Method: best-of-N wall time (best, not mean, to suppress scheduler noise); single-shot processes, no warm-up beyond the script's own loop.
  • Runtimes: ruby (MRI, the oracle) and ruby --yjit; jruby (on the JVM); truffleruby (GraalVM). JRuby and TruffleRuby are timed cold, single-shot, so they carry JVM / Graal startup on every run.
  • The benchmark script and harness live in rbgo's repo under bench/modules/ (time.rb + run.sh). Reproduce: RBGO=./rbgo TRUFFLE=truffleruby bash bench/modules/run.sh 5.

Cross-runtime numbers pending

The full cross-runtime table (rbgo / MRI / YJIT / JRuby / TruffleRuby) for this module is produced by the rbgo per-module parity run and is not yet recorded here — rather than paste fabricated figures, this page documents the methodology and points at the harness. The table will be filled in from a real measured run, the same way the sibling go-ruby-yaml page reports its numbers.

Honest framing

JRuby and TruffleRuby are timed cold, single-shot, so they carry JVM / Graal startup on every run — read them as one-shot ruby file.rb costs, the same way rbgo and MRI are measured, not as steady-state JIT numbers. Rows that complete in well under ~200 ms carry the most relative noise; treat their ratios as order-of-magnitude.