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http://tmm1.net/ruby21-objspace/ https://github.com/ruby/ruby/blob/trunk/include/ruby/ruby.h https://github.com/ruby/ruby/blob/trunk/include/ruby/ruby.h#L485-L517

https://eaton.party/blog/configuring-docker-for-crystal-development

https://anomaly.io/understand-auto-cross-correlation-normalized-shift/index.html https://anomaly.io/detect-correlation-time-series/

Single pass across each line

crystal build --verbose src/dumpster.cr --link-flags "-L /nix/store/zbw5w43lhbp7lrn7j5hcj36j1whdff92-liblapack-3.8.0/lib"

docker exec engine rbtrace -p 1 -e 'Thread.new{GC.start;require "objspace";ObjectSpace.trace_object_allocations_start}.join'

docker exec engine rbtrace -p 1 -e 'Thread.new{GC.start;require "objspace";io=File.open("/tmp/ruby-heap.dump", "w"); ObjectSpace.dump_all(output: io); io.close}.join'

Provide ability to filter using BM (based on cmd line options)

For filtering by class - BM scan for class entry, then use address in BM scan for lines referencing it.

When reading, use pos/file.size to update progress

Keep hash of class address -> name Count min sketch for grouping

  1. BM search for ' "type":"'
  2. Case on first char to detect type and define jump
  3. For fast search extract address, for full use gets prepend '{' and extract as JSON

extract char_at - check for 'O' or 'C'

Sub-problems

  • line segmentation / iteration
  • entry discard / pre-parse
  • entry parsing
  • space-bounded counting

+++++

$ dumpster Usage: dumpster [OPTION]... FILE Try 'dumpster --help' for more information.

$ dumpster --help Usage: dumpster [OPTION]... FILE Analyses the contents of a Ruby MRI heap dump in FILE.

-q, --quick provide a partial analysis (instance counts only) -n, --num=COUNT show top COUNT objects in metrics (default: 20) -g, --generation=NUM only inspect objects allocated in generation NUM -f, --file=PATTERN only inspect objects instantiated within files matching PATTERN -c, --class=NAME only inspect objects of class NAME

$ dumpster ruby-heap.dump --quick ◢ Analysing (34%)

... Found 37678936 heap objects

► Top objects by instance count 89098 Foo::Bar 9809 Test::A 4377 A::B 9309 C::Hkkljfs

$ dumpster ruby-heap.dump

Found 37678936 objects Built from 4787 classes Using 34995MiB of memory

► Top allocations by location 1245 /foo/bar:6

► Top instances by count 1 Foo::Bar 9809 Test::A 4377 A::B 9309 C::Hkkljfs

► Top instances by memory usage

► Top allocations by generation Gen | Objects | Mem usage

  •     23497

17 879 18 769 19 9876 20 67

$ dumpster --help Usage: dumpster [OPTION]... FILE Analyses the contents of a Ruby MRI heap dump in FILE to detect potential memory leaks.

-n, --num=COUNT show top COUNT objects in metrics (default: 20) -f, --file=PATTERN only inspect objects instantiated within files matching PATTERN -c, --class=PATTERN only inspect objects where the base class matches PATTERN -l, --locations-only provide locations of interest only -t, --types-only provide instance types only -m, --machine-readable output CSV data only to STDOUT for piping to other processes

$ dumpster ruby-heap.dump

Parsed 37678936 active objects Across 583 generations

► Locations of interest Growth | Instances | Type | Location 0.26 12345 STRING /foo/bar:6

► Types of interest Growth | Instances | Class 0.26 12345 Foo::Bar::Example

$ dumpster ruby-heap.dump

Parsed 37678936 active objects Across 4 generations

warning: only a small number of GC generations parsed, accuracy of the below analysis may be questionable...

► Locations of interest Growth | Instances | Type | Location 0.26 12345 STRING /foo/bar:6

► Types of interest Growth | Instances | Class 0.26 12345 Foo::Bar::Example

$ dumpster ruby-heap.dump

Parsed 37678936 active objects Across 1 generations

error: not enough GC generations included within the dump file