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Diffstat (limited to 'man')
| -rw-r--r-- | man/ruby.1 | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/man/ruby.1 b/man/ruby.1 index 8f0c0d1ae7..c35f130557 100644 --- a/man/ruby.1 +++ b/man/ruby.1 @@ -482,6 +482,95 @@ as below. % gem help .Ed .Pp +.Sh GC ENVIRONMENT +The Ruby garbage collector (GC) tracks objects in fixed-sized slots, +but each object may have auxillary memory allocations handled by the +malloc family of C standard library calls ( +.Xr malloc 3 , +.Xr calloc 3 , +and +.Xr realloc 3 ) . +In this documentatation, the "heap" refers to the Ruby object heap +of fixed-sized slots, while "malloc" refers to auxillary +allocations commonly referred to as the "process heap". +Thus there are at least two possible ways to trigger GC: +.Bl -hang -offset indent +.It Sy 1 +Reaching the object limit. +.It Sy 2 +Reaching the malloc limit. +.Pp +.El +In Ruby 2.1, the generational GC was introduced and the limits are divided +into young and old generations, providing two additional ways to trigger +a GC: +.Bl -hang -offset indent +.It Sy 3 +Reaching the old object limit. +.It Sy 4 +Reaching the old malloc limit. +.El +.Pp +There are currently 4 possible areas where the GC may be tuned by +the the following 11 environment variables: +.Bl -hang -compact -width "RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR" +.It Ev RUBY_GC_HEAP_INIT_SLOTS +Initial allocation slots. Introduced in Ruby 2.1, default: 10000. +.Pp +.It Ev RUBY_GC_HEAP_FREE_SLOTS +Prepare at least this amount of slots after GC. +Allocate this number slots if there are not enough slots. +Introduced in Ruby 2.1, default: 4096 +.Pp +.It Ev RUBY_GC_HEAP_GROWTH_FACTOR +Increase allocation rate of heap slots by this factor. +Introduced in Ruby 2.1, default: 1.8, minimum: 1.0 (no growth) +.Pp +.It Ev RUBY_GC_HEAP_GROWTH_MAX_SLOTS +Allocation rate is limited to this number of slots, +preventing excessive allocation due to RUBY_GC_HEAP_GROWTH_FACTOR. +Introduced in Ruby 2.1, default: 0 (no limit) +.Pp +.It Ev RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR +Perform a full GC when the number of old objects is more than R * N, +where R is this factor and N is the number of old objects after the +last full GC. +Introduced in Ruby 2.1.1, default: 2.0 +.Pp +.It Ev RUBY_GC_MALLOC_LIMIT +The initial limit of young generation allocation from the malloc-family. +GC will start when this limit is reached. +Default: 16MB +.Pp +.It Ev RUBY_GC_MALLOC_LIMIT_MAX +The maximum limit of young generation allocation from malloc before GC starts. +Prevents excessive malloc growth due to RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR. +Introduced in Ruby 2.1, default: 32MB. +.Pp +.It Ev RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR +Increases the limit of young generation malloc calls, reducing +GC frequency but increasing malloc growth until RUBY_GC_MALLOC_LIMIT_MAX +is reached. +Introduced in Ruby 2.1, default: 1.4, minimum: 1.0 (no growth) +.Pp +.It Ev RUBY_GC_OLDMALLOC_LIMIT +The initial limit of old generation allocation from malloc, +a full GC will start when this limit is reached. +Introduced in Ruby 2.1, default: 16MB +.Pp +.It Ev RUBY_GC_OLDMALLOC_LIMIT_MAX +The maximum limit of old generation allocation from malloc before a +full GC starts. +Prevents excessive malloc growth due to RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR. +Introduced in Ruby 2.1, default: 128MB +.Pp +.It Ev RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR +Increases the limit of old generation malloc allocation, reducing full +GC frequency but increasing malloc growth until RUBY_GC_OLDMALLOC_LIMIT_MAX +is reached. +Introduced in Ruby 2.1, default: 1.2, minimum: 1.0 (no growth) +.Pp +.El .Sh STACK SIZE ENVIRONMENT Stack size environment variables are implementation-dependent and subject to change with different versions of Ruby. The VM stack is used @@ -510,6 +599,7 @@ default: 65536 or 131072 Machine stack size used at fiber creation. default: 262144 or 524288 .Pp +.El .Sh SEE ALSO .Bl -hang -compact -width "http://www.ruby-lang.org/123" .It https://www.ruby-lang.org/ |