heapviz

Heapviz

Warning: This probably shouldn't be used for anything important. It requires patching and building a custom Ruby

Produces a png of a json dump of the Ruby objspace. Heap dump images are organised in rows and columns:

• A heap page is a vertical column 4 pixels wide
• A slot is a vertical chunk that is 4 pixels wide and (4*slot_size/sizeof(RVALUE)) tall. so 40 byte slots are 4x4 pixels, 80 bytes slots are 4x8 pixels, 160 bytes are 4x16 pixels and so on.

Running

This script requires a commit that recently landed on Ruby master to add a slot_size field to the output of ObjectSpace.dump_all. Use your Ruby version manager of choice to install the development release of Ruby and then write a script that dumps the heap to a file.

require 'objspace'
ObjectSpace.dump_all(output: File.new("output.json", "w"))

Run it with Ruby

./ruby test.rb

Then run this script with your json output, and a filename of a png to write to (the png doesn't need to exist)

../heapviz/exe/heapviz output.json output.png
open output.png