When profiling NodeJS using --inspect, what does "(program)" mean

11
votes

When using node --inspect to profile a NodeJS application using chrome dev tools, a large part of the runtime is spent in (program). I did not find information on what exactly this means? Is it just time spend in the C++ parts of NodeJS?

1
node.jsprofiling

1 Answers

0
votes

The (program) entry is Chrome itself - it's the first thing that gets executed before anything else and remains there regardless of what your Node application is doing.

There is discussion in this Chromium profiler issue on what exactly it means (and whether or not it's confusing).

You can also see in the comments of the Changelog for the commit also includes the following comment:

Web Inspector: [Chromium] profiler - differentiate between native code (program) and idle time https://bugs.webkit.org/show_bug.cgi?id=88446

Reviewed by NOBODY (OOPS!).

Now idleTime is supplied in profile object. In this patch, idleTime, if any, is subtracted from "(program)" node, and new node "(idle)" is injected as a top level node ti profile.