Adding Compare in torch.utils.benchmark documentation (#125009)

`torch.utils.benchmark.Compare` is not directly exposed in torch.utils.benchmark documentation.

I think this is a valuable resource to add since it can help people embracing the torch benchmark way of doing things, and help people building documentation towards it.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/125009
Approved by: https://github.com/mikaylagawarecki

docs/source/benchmark_utils.rst

@@ -19,6 +19,9 @@ Benchmark Utils - torch.utils.benchmark
 .. autoclass:: FunctionCounts
     :members:
 
+.. autoclass:: Compare
+    :members:
+
 .. These are missing documentation. Adding them here until a better place
 .. is made in this file.
 .. py:module:: torch.utils.benchmark.examples

torch/utils/benchmark/utils/compare.py

@@ -267,6 +267,21 @@ Times are in {common.unit_to_english(self.time_unit)}s ({self.time_unit}).
 
 
 class Compare:
+    """Helper class for displaying the results of many measurements in a
+    formatted table.
+
+    The table format is based on the information fields provided in
+    :class:`torch.utils.benchmark.Timer` (`description`, `label`, `sub_label`,
+    `num_threads`, etc).
+
+    The table can be directly printed using :meth:`print` or casted as a `str`.
+
+    For a full tutorial on how to use this class, see:
+    https://pytorch.org/tutorials/recipes/recipes/benchmark.html
+
+    Args:
+        results: List of Measurment to display.
+    """
     def __init__(self, results: List[common.Measurement]):
         self._results: List[common.Measurement] = []
         self.extend_results(results)
@@ -278,6 +293,10 @@ class Compare:
         return "\n".join(self._render())
 
     def extend_results(self, results):
+        """Append results to already stored ones.
+
+        All added results must be instances of ``Measurement``.
+        """
         for r in results:
             if not isinstance(r, common.Measurement):
                 raise ValueError(
@@ -286,15 +305,22 @@ class Compare:
         self._results.extend(results)
 
     def trim_significant_figures(self):
+        """Enables trimming of significant figures when building the formatted table."""
         self._trim_significant_figures = True
 
     def colorize(self, rowwise=False):
+        """Colorize formatted table.
+
+        Colorize columnwise by default.
+        """
         self._colorize = Colorize.ROWWISE if rowwise else Colorize.COLUMNWISE
 
     def highlight_warnings(self):
+        """Enables warning highlighting when building formatted table."""
         self._highlight_warnings = True
 
     def print(self):
+        """Print formatted table"""
         print(str(self))
 
     def _render(self):