Issue #14718 has been updated by mperham (Mike Perham). Hi Yusuke, I'm sorry if this hasn't been approached the right way. **The Problem**: Many large Rails apps have a memory fragmentation problem on 64-bit Linux. I hear reports of excessive memory consumption from users every day, I linked some of those tweets above. **The Immediate Solution**: Tune arenas, see #14759. This seems to greatly reduce memory fragmentation. This is a glibc developer's recommendation: > Therefore the solution to a program with lots of threads is to limit the arenas as a trade-off for memory. I'm working on a script which reproduces the memory fragmentation but it requires a dedicated large 64-bit Linux machine instance, with many gigabytes of RAM. Jemalloc might be a good long-term solution; I will try to get you a script so we can show you the memory improvement, not just say it. :-) ---------------------------------------- Feature #14718: Use jemalloc by default? https://bugs.ruby-lang.org/issues/14718#change-72010 * Author: mperham (Mike Perham) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- I know Sam opened #9113 4 years ago to suggest this but I'm revisiting the topic to see if there's any movement here for Ruby 2.6 or 2.7. I supply a major piece of Ruby infrastructure (Sidekiq) and I keep hearing over and over how Ruby is terrible with memory, a huge memory hog with their Rails apps. My users switch to jemalloc and a miracle occurs: their memory usage drops massively. Some data points: https://twitter.com/brandonhilkert/status/987400365627801601 https://twitter.com/d_jones/status/989866391787335680 https://github.com/mperham/sidekiq/issues/3824#issuecomment-383072469 Redis moved to jemalloc many years ago and it solved all of their memory issues too. Their conclusion: the glibc allocator "sucks really really hard". http://oldblog.antirez.com/post/everything-about-redis-24.html This is a real pain point for the entire Rails community and would improve Ruby's reputation immensely if we can solve this problem. -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>