README.md in stackprof-0.2.15 vs README.md in stackprof-0.2.16

@@ -107,12 +107,12 @@
 
 ## Sampling
 
 four sampling modes are supported:
 
-  - :wall (using `ITIMER_REAL` and `SIGALRM`)
-  - :cpu (using `ITIMER_PROF` and `SIGPROF`) [default mode]
+  - :wall (using `ITIMER_REAL` and `SIGALRM`) [default mode]
+  - :cpu (using `ITIMER_PROF` and `SIGPROF`)
   - :object (using `RUBY_INTERNAL_EVENT_NEWOBJ`)
   - :custom (user-defined via `StackProf.sample`)
 
 samplers have a tuneable interval which can be used to reduce overhead or increase granularity:
 
@@ -139,10 +139,16 @@
 StackProf.run(mode: :object, out: 'tmp/stackprof.dump', interval: 1) do
   #...
 end
 ```
 
+by default, samples taken during garbage collection will show as garbage collection frames
+including both mark and sweep phases. for longer traces, these can leave gaps in a flamegraph
+that are hard to follow and can be disabled by setting the `ignore_gc` option to true.
+garbage collection time will still be present in the profile but not explicitly marked with
+its own frame.
+
 samples are taken using a combination of three new C-APIs in ruby 2.1:
 
   - signal handlers enqueue a sampling job using `rb_postponed_job_register_one`.
     this ensures callstack samples can be taken safely, in case the VM is garbage collecting
     or in some other inconsistent state during the interruption.
@@ -326,9 +332,10 @@
 Option      | Meaning
 -------     | ---------
 `mode`      | mode of sampling: `:cpu`, `:wall`, `:object`, or `:custom` [c.f.](#sampling)
 `out`       | the target file, which will be overwritten
 `interval`  | mode-relative sample rate [c.f.](#sampling)
+`ignore_gc` | Ignore garbage collection frames
 `aggregate` | defaults: `true` - if `false` disables [aggregation](#aggregation)
 `raw`       | defaults `false` - if `true` collects the extra data required by the `--flamegraph` and `--stackcollapse` report types
 `metadata`  | defaults to `{}`. Must be a `Hash`. metadata associated with this profile
 `save_every`| (rack middleware only) write the target file after this many requests