Nodejs Profiling: What to do with v8.log file

You need to process the v8.log. The v8 log contains sample points, and want to collect that data into something readable/usable. Check out node-tick-processor and run that over your v8 log.

Starting with v5.2.0, Node.JS ships with a built-in tick processor:

node --prof-process

See the release notes for more information.

Chrome's built-in Trace Event Profiling Tool (accessible in Chrome or Chromium at chrome://tracing) can build more-useful visualizations around v8.log output.

Note that dumps from node >= 0.11.x may be more useful to you than those on the current stable release (0.10.35).