Document --benchmark_filter. Thanks to NAThompson for the original patch
diff --git a/README.md b/README.md
index af99401..0993952 100644
--- a/README.md
+++ b/README.md
@@ -462,6 +462,24 @@
}
```
+## Running a subset of the benchmarks
+
+The `--benchmark_filter=<regex>` option can be used to only run the benchmarks
+which match the specified `<regex>`. For example:
+
+```bash
+$ ./run_benchmarks.x --benchmark_filter=BM_memcpy/32
+Run on (1 X 2300 MHz CPU )
+2016-06-25 19:34:24
+Benchmark Time CPU Iterations
+----------------------------------------------------
+BM_memcpy/32 11 ns 11 ns 79545455
+BM_memcpy/32k 2181 ns 2185 ns 324074
+BM_memcpy/32 12 ns 12 ns 54687500
+BM_memcpy/32k 1834 ns 1837 ns 357143
+```
+
+
## Output Formats
The library supports multiple output formats. Use the
`--benchmark_format=<console|json|csv>` flag to set the format type. `console`
