Graphs from valgrind’s massif

Valgrind’s massif tool tracks how much memory an application uses over time, allowing you to see leaks. Previous versions produced pretty graphs. For instance, see the graph in this out-dated GNOME tutorial about massif.

However, massif’s behaviour has changed and those graphs are no longer generally appropriate. But they were nice. So I hacked a copy of the current ms_print perl code, producing massif_grapher. Forgive me for my perl code.

I used perl’s GD::Graph module. It worked but it’s a little eccentric. The image size is hard-coded and needs to be increased in the code when Gd::Graph complains that the vertical or horizontal space is too small, if you have too many data points. outputs a massif_pretty.png file:

  • There’s a simple graph (the default) that just shows the stack and heap allocations, splitting the heap up into useful and extra (allocated as an optimization) . It doesn’t mention any functions. See this example.
  • And there’s a detailed graph (via –detailed) that tries to show the old-style cumulative graph, with color for each allocating function. See this example. I won’t put it directly in my blog because their’s some obviously weird stuff happening at the top. Also, the legend needs to be reversed so it’s easier to associate the functions with the blocks on the graph. Patches welcome. You’ll get weird results if you don’t specify–detailed-freq=1 to massif.

Time will tell if this is useful.

Other useful massif tools:

  • Eclipse Linux Tools’ valgrind support: Scroll down to see the video for their massif support. This allows you to jump right to the code. Useful if you are using Eclipse.
  • massiftool: A Qt-based application for navigating massif snapshot data.

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