SimplePerf Usage

I'm trying to run Simpleperf to get a CPU trace of a Unity Project. The instructions seem to be missing steps.

I cannot successfully run either the `binary_cache_builder` (missing `perf.data`) or `app_profiler.py` to generate a `perf.data` file.

I'm following instructions here: https://developer.oculus.com/documentation/unity/ts-simpleperf/ 

1. Running `binary_cache_builder` requires a "perf.data" file that is missing.

```
Android\Sdk\ndk\21.4.7075529\simpleperf> python binary_cache_builder.py -lib "C:\Users\suv\Desktop\test-0.1-v1.symbols"

Traceback (most recent call last):

  File "binary_cache_builder.py", line 237, in <module>

    main()

  File "binary_cache_builder.py", line 228, in main

    args = parser.parse_args()

  File "C:\Python27\lib\argparse.py", line 1656, in parse_args

    args, argv = self.parse_known_args(args, namespace)

  File "C:\Python27\lib\argparse.py", line 1678, in parse_known_args

    default = self._get_value(action, default)

  File "C:\Python27\lib\argparse.py", line 2203, in _get_value

    raise ArgumentError(action, msg)

argparse.ArgumentError: argument -i/--perf_data_path: C:\Users\suv\AppData\Local\Android\Sdk\ndk\21.4.7075529\simpleperf\perf.data is not a file.

Running `app_profiler.py` fails to generate "perf.data" file

``` Android\Sdk\ndk\21.4.7075529\simpleperf>python app_profiler.py --disable_adb_root --ndk_path ```
```
"C:\Users\suv\AppData\Local\Android\Sdk\ndk" --app com.facebook.together.together.stable -r "-g --duration 50 -e cpu-cycles,cache-misses"

INFO:root:prepare profiling

INFO:root:start profiling

INFO:root:run adb cmd: ['\\Users\\suv\\AppData\\Local\\Android\\sdk\\ndk-bundle\\..\\platform-tools\\adb', 'shell', '/data/local/tmp/simpleperf', 'record', '-o', '/data/local/tmp/perf.data', '-g --duration 50 -e cpu-cycles,cache-misses', '--log', 'info', '--app', 'com.facebook.together.together.stable']

Failed to record profiling data.
```