More memory profiling

spec/memprof.rb

@@ -0,0 +1,37 @@
+require 'objspace'
+
+module MemoryUsage
+  MemoryReport = Struct.new(:total_memsize)
+
+  def self.full_gc
+    GC.start(full_mark: true)
+  end
+
+  def self.report(&block)
+    rvalue_size = GC::INTERNAL_CONSTANTS[:RVALUE_SIZE]
+
+    full_gc
+    GC.disable
+
+    total_memsize = 0
+
+    generation = nil
+    ObjectSpace.trace_object_allocations do
+      generation = GC.count
+      block.call
+    end
+
+    ObjectSpace.each_object do |obj|
+      next unless generation == ObjectSpace.allocation_generation(obj)
+      memsize = ObjectSpace.memsize_of(obj) + rvalue_size
+      # compensate for API bug
+      memsize = rvalue_size if memsize > 100_000_000_000
+      total_memsize += memsize
+    end
+
+    GC.enable
+    full_gc
+
+    return MemoryReport.new(total_memsize)
+  end
+end

spec/model_spec.rb

@@ -1,14 +1,14 @@
 require 'spec_helper'
 require 'memory_profiler'
 
+def Process.rss; `ps -o rss= -p #{Process.pid}`.chomp.to_i; end
+
 describe Ebooks::Model do
   it "does not use a ridiculous amount of memory" do
-    RubyProf.start
-    Ebooks::Model.consume(path("data/0xabad1dea.json"))
-    result = RubyProf.stop
+    report = MemoryUsage.report do
+      model = Ebooks::Model.consume(path("data/0xabad1dea.json"))
+    end
 
-    require 'pry'; binding.pry
-
-    expect(report.total_retained).to be < 100000
+    expect(report.total_memsize).to be < 1000000000
   end
 end

spec/spec_helper.rb

@@ -1,4 +1,5 @@
 require 'twitter_ebooks'
+require_relative 'memprof'
 
 def path(relpath)
   File.join(File.dirname(__FILE__), relpath)