From: ko1@... Date: 2018-08-08T06:10:25+00:00 Subject: [ruby-core:88343] [Ruby trunk Feature#14759] [PATCH] set M_ARENA_MAX for glibc malloc Issue #14759 has been updated by ko1 (Koichi Sasada). sam.saffron (Sam Saffron) wrote: > Koichi / Nobu > > Is there any chance we can merge this in and even backport to 2.4/2.5. > > It is a very safe change for now and users can override the behavior if they need to using ENV (rare cases where you say host a ton of V8 runtimes) > > It will give Ruby a much better reputation to have this out there and guilds are a few releases out. We are not maintainers for both versions, but I think we shouldn't backport it because we can change this parameter by an environment variable. ---------------------------------------- Feature #14759: [PATCH] set M_ARENA_MAX for glibc malloc https://bugs.ruby-lang.org/issues/14759#change-73371 * 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: