From: dennisb55@... Date: 2019-03-15T06:54:12+00:00 Subject: [ruby-core:91844] [Ruby trunk Feature#14759] [PATCH] set M_ARENA_MAX for glibc malloc Issue #14759 has been updated by bluz71 (Dennis B). Hongli Lai's [What causes Ruby memory bloat?](https://www.joyfulbikeshedding.com/blog/2019-03-14-what-causes-ruby-memory-bloat.html) post is most-interesting indeed. That article has given rise to a new issue, opened by Sam Saffron, [Introduce malloc_trim(0) in full gc cycles #15667](https://bugs.ruby-lang.org/issues/15667). If `malloc_trim` does not have any deleterious performance demons (to-be-determined) then there would be a very strong case to add a call to it in the the Ruby GC hence rendering this issue completely moot. We await real-world results of [#15667](https://bugs.ruby-lang.org/issues/15667) ---------------------------------------- Feature #14759: [PATCH] set M_ARENA_MAX for glibc malloc https://bugs.ruby-lang.org/issues/14759#change-77112 * Author: normalperson (Eric Wong) * Status: Open * Priority: Normal * Assignee: * Target version: ---------------------------------------- Not everybody benefits from jemalloc and the extra download+install time is not always worth it. Lets make the user experience for glibc malloc users better, too. Personally, I prefer using M_ARENA_MAX=1 (via MALLOC_ARENA_MAX env) myself, but there is currently a performance penalty for that. gc.c (Init_GC): set M_ARENA_MAX=2 for glibc malloc glibc malloc creates too many arenas and leads to fragmentation. Given the existence of the GVL, clamping to two arenas seems to be a reasonable trade-off for performance and memory usage. Some users (including myself for several years, now) prefer only one arena, now, so continue to respect users' wishes when MALLOC_ARENA_MAX is set. Thanks to Mike Perham for the reminder [ruby-core:86843] This doesn't seem to conflict with jemalloc, so it should be safe for all glibc-using systems. ---Files-------------------------------- 0001-gc.c-Init_GC-set-M_ARENA_MAX-2-for-glibc-malloc.patch (1.46 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: