[Someone]

This times performance like this:

  $ time ./crb

That means time spent writing the .ppm file is included.

In the implementations I browsed, that is about a million print calls, each of which might flush the output buffer, and whose performance may depend on locale.

To benchmark ray tracing I would, instead, just output the sum of the pixel values, or set the exit code depending on that value.

Even though ray tracing is cpu intensive, it also wouldn’t completely surprise me if some of the implementations in less mature languages spent significant time writing that output because their programmers haven’t come around to optimizing such code.

[weberc2]

The Go version spends 8 seconds writing data. This is probably par for the course for most implementations.