Class Benchmark

src/test/java/net/starlark/java/eval/Benchmarks.java:284–383

  // The type of the parameter to each bench(b) function.
  // Provides n, the number of iterations.
  @StarlarkBuiltin(name = "Benchmark")
  private static class Benchmark implements StarlarkValue {

    private final String name;
    private final StarlarkFunction f;

    // The cast assumes we use the "Sun" JVM, which measures per-thread allocation and CPU.
    private final ThreadMXBean threadMX = (ThreadMXBean) ManagementFactory.getThreadMXBean();

    // Starlark attributes
    private int n; // requested number of iterations

    // current span  (time0 != 0 => started)
    private long cpu0;
    private long alloc0;
    private long time0;
    private long steps0;

    // accumulators
    private int count; // iterations
    private long cpu; // CPU time (ns) in this thread
    private long alloc; // bytes allocated by this thread
    private long time; // wall time (ns)
    private long steps; // Starlark computation steps

    private Benchmark(String name, StarlarkFunction f) {
      this.name = name;
      this.f = f;
    }

    // Runs n iterations of this benchmark and reports success.
    private boolean runIterations(StarlarkThread thread, int n) {
      this.n = n;
      try {
        start(thread);
        Starlark.positionalOnlyCall(thread, f, this);
        stop(thread);
        this.count += n;

      } catch (EvalException ex) {
        System.err.println(ex.getMessageWithStack());
        return false;

      } catch (
          @SuppressWarnings("InterruptedExceptionSwallowed")
          Throwable ex) {
        // unhandled exception (incl. InterruptedException)
        System.err.printf("In %s: %s\n", name, ex.getMessage());
        ex.printStackTrace();
        return false;
      }
      return true;
    }

    @StarlarkMethod(name = "n", doc = "Requested number of iterations.", structField = true)
    public int n() {
      return n;
    }