by gaffneyc

GitHub Readme.md


TCMalloc is a thread-caching malloc implementation designed to reduce fragmentation in multithreaded applications. This buildpack makes it easy to install and use TCMalloc on Heroku and compatible platforms.


heroku buildpacks:add https://github.com/gaffneyc/heroku-buildpack-tcmalloc.git
git push heroku master



Set the TCMALLOC_ENABLED config option to true and tcmalloc will be used for all commands run inside of your dynos.

heroku config:set TCMALLOC_ENABLED=true

Per dyno

To control when tcmalloc is configured on a per dyno basis use tcmalloc.sh <cmd> and ensure that TCMALLOC_ENABLED is unset.

Example Procfile:

web: tcmalloc.sh bundle exec puma -C config/puma.rb



Set this to true to automatically enable tcmalloc.

heroku config:set TCMALLOC_ENABLED=true

To disable tcmalloc set the option to false. This will cause the application to restart disabling tcmalloc.

heroku config:set TCMALLOC_ENABLED=false


Set this to select or pin to a specific version of tcmalloc. The default is to use the latest stable version if this is not set. You will receive an error mentioning tar if the version does not exist.

Default: 2.7

note: This setting is only used during slug compilation. Changing it will require a code change to be deployed in order to take affect.

heroku config:set TCMALLOC_VERSION=2.7

Available Versions

Version 2.7

The complete and most up to date list of supported versions and stacks is available on the releases page.


This uses Docker to build against Heroku stack-image-like images.

make VERSION=2.7

Artifacts will be dropped in dist/ based on Heroku stack and tcmalloc version.

Deploying New Versions

  • make VERSION=X.Y.Z
  • open dist
  • Go to releases
  • Edit the release corresponding to each heroku Stack
  • Drag and drop the new build to attach

Creating a New Stack

  • Go to releases
  • Click "Draft a new release"
  • Tag is the name of the Stack (e.g. heroku-18)
  • Target is release-master
  • Title is Builds for the [stack] stack


Development of the TCMalloc buildpack is sponsored by Dead Man's Snitch, a monitoring service for cron jobs and other scheduled tasks. Running backups, invoicing, or other critical jobs on a regular basis? Dead Man's Snitch gives you the peace of mind that they're actually working.