Apparently it's slow because of marking everything?

gistfile1.txt

Samples: 8K of event 'cycles', Event count (approx.): 367381525322, DSO: ruby_memprofiler_pprof_ext.so
  Children      Self  Comm  Symbol
+   60.45%     0.00%  ruby  [.] collector_cdata_gc_mark                                                                              ▒
+   60.34%     0.03%  ruby  [.] collector_gc_mark_each_heap_sample                                                                   ▒
+   60.30%     0.26%  ruby  [.] mpp_sample_gc_mark                                                                                   ▒
+    0.74%     0.00%  ruby  [.] collector_tphook_newobj                                                                              ▒
     0.04%     0.00%  ruby  [.] collector_tphook_freeobj                                                                             ▒
     0.02%     0.01%  ruby  [.] mpp_rb_gc_disable_no_rest                                                                            ▒
     0.01%     0.01%  ruby  [.] backtracie_bt_gc_mark_moveable@plt                                                                   ▒
     0.01%     0.01%  ruby  [.] rb_current_vm                                                                                        ▒
     0.01%     0.01%  ruby  [.] rb_gc_enable@plt                                                                                     ▒
     0.01%     0.00%  ruby  [.] collector_mark_sample_value_as_freed                                                                 ▒
     0.01%     0.00%  ruby  [.] mpp_sample_refcount_dec