Any reasons to run or not run Jemalloc on Heroku?
https://egghead.io uses it.
Here are a few links
I’m convinced that tuning glibc is a no brainer. Set MALLOC_ARENA_MAX=2 everywhere you start Sidekiq and enjoy your extra memory. Using jemalloc is more complex. Memory bloat has been a serious issue in large scale Rails apps as far back as I can remember in Ruby. I wish ruby-core would pull in jemalloc as the default allocator but they seem content with glibc.
The potential memory savings here are so great and the penalties so minor that I would recommend that if you are using Ruby and Puma or Sidekiq in production, you should always use jemalloc.