Collect specialization statistics from running benchmarks (#140)

doc/run_benchmark.rst

@@ -191,4 +191,16 @@ mentioned above. Running an arbitrary number of warmup values may also make
 the benchmark less reliable since two runs may use a different number of warmup
 values.
 
+Specializer statistics (``pystats``)
+==================================
 
+``pyperf`` has built-in support for `specializer statistics (``pystats``) <https://docs.python.org/dev/using/configure.html#cmdoption-enable-pystats>`_.
+If running benchmarks on a CPython built with the ``--enable-pystats`` flag, pyperf will automatically collect ``pystats`` on the benchmark code by calling ``sys._stats_on`` immediately before the benchmark and calling ``sys._stats_off`` immediately after.
+Stats are not collected when running ``pyperf``'s own code or when warming up or calibrating the benchmarks.
+
+Due to the overhead of collecting the statistics, the timing results will be meaningless.
+
+The `Tools/scripts/summarize_stats.py <https://github.com/python/cpython/blob/main/Tools/scripts/summarize_stats.py>`_ script can be used to summarize the statistics in a human-readable form.
+
+Statistics are not cleared between runs.
+If you need to delete statistics from a previous run, remove the files in ``/tmp/py_stats`` (Unix) or ``C:\temp\py_stats`` (Windows).

pyperf/_collect_metadata.py

@@ -116,6 +116,10 @@ def collect_python_metadata(metadata):
         if not gc.isenabled():
             metadata['python_gc'] = 'disabled'
 
+    # pystats enabled?
+    if hasattr(sys, "_stats_clear"):
+        metadata['pystats'] = 'enabled'
+
 
 def read_proc(path):
     path = proc_path(path)

pyperf/_runner.py

@@ -77,6 +77,13 @@ def __init__(self, values=None, warmups=None, processes=None,
                  program_args=None, add_cmdline_args=None,
                  _argparser=None):
 
+        # Reset the stats collection if running a --enable-pystats build
+        try:
+            sys._stats_off()
+            sys._stats_clear()
+        except AttributeError:
+            pass
+
         # Watchdog: ensure that only once instance of Runner (or a Runner
         # subclass) is created per process to prevent bad suprises
         cls = self.__class__

pyperf/_worker.py

@@ -56,6 +56,22 @@ def _compute_values(self, values, nvalue,
         else:
             value_name = 'Value'
 
+        task_func = self.task_func
+
+        # If we are on a pystats build, turn on stats collection around the
+        # actual work, but only if we aren't warming up or calibrating.
+        if hasattr(sys, "_stats_on") and not is_warmup and not calibrate_loops:
+            core_task_func = task_func
+
+            def stats_func(*args):
+                sys._stats_on()
+                try:
+                    return core_task_func(*args)
+                finally:
+                    sys._stats_off()
+
+            task_func = stats_func
+
         index = 1
         inner_loops = self.inner_loops
         if not inner_loops:
@@ -64,7 +80,7 @@ def _compute_values(self, values, nvalue,
             if index > nvalue:
                 break
 
-            raw_value = self.task_func(self, self.loops)
+            raw_value = task_func(self, self.loops)
             raw_value = float(raw_value)
             value = raw_value / (self.loops * inner_loops)