[benchmark] LogParser measure environment

Measure more of environment during test

In addition to measuring maximum resident set size, also extract number of voluntary and involuntary context switches from the verbose mode.

benchmark/scripts/compare_perf_tests.py

@@ -145,7 +145,14 @@ class LogParser(object):
 
     def __init__(self):
         """Create instance of `LogParser`."""
-        self.results, self.samples, self.num_iters = [], [], 1
+        self.results = []
+        self._reset()
+
+    def _reset(self):
+        """Reset parser to the default state for reading a new result."""
+        self.samples, self.num_iters = [], 1
+        self.max_rss, self.mem_pages = None, None
+        self.voluntary_cs, self.involuntary_cs = None, None
 
     # Parse lines like this
     # #,TEST,SAMPLES,MIN(μs),MAX(μs),MEAN(μs),SD(μs),MEDIAN(μs)
@@ -158,16 +165,25 @@ class LogParser(object):
         if len(columns) < 8:
             columns = result.split()
         r = PerformanceTestResult(columns)
+        if self.max_rss:
+            r.max_rss = self.max_rss
+            r.mem_pages = self.mem_pages
+            r.voluntary_cs = self.voluntary_cs
+            r.involuntary_cs = self.involuntary_cs
         if self.samples:
             r.all_samples = self.samples
         self.results.append(r)
-        self.num_iters, self.samples = 1, []
+        self._reset()
+
+    def _store_memory_stats(self, max_rss, mem_pages):
+        self.max_rss = int(max_rss)
+        self.mem_pages = int(mem_pages)
 
     # Regular expression and action to take when it matches the parsed line
     state_actions = {
         results_re: _append_result,
 
-        # Verbose mode adds two new productions:
+        # Verbose mode adds new productions:
         # Adaptively determined N; test loop multiple adjusting runtime to ~1s
         re.compile(r'\s+Measuring with scale (\d+).'):
         (lambda self, num_iters: setattr(self, 'num_iters', num_iters)),
@@ -176,6 +192,16 @@ class LogParser(object):
         (lambda self, i, runtime:
          self.samples.append((int(i), int(self.num_iters), int(runtime)))
         ),
+
+        # Environmental statistics: memory usage and context switches
+        re.compile(r'\s+MAX_RSS \d+ - \d+ = (\d+) \((\d+) pages\)'):
+        _store_memory_stats,
+
+        re.compile(r'\s+VCS \d+ - \d+ = (\d+)'):
+        (lambda self, vcs: setattr(self, 'voluntary_cs', int(vcs))),
+
+        re.compile(r'\s+ICS \d+ - \d+ = (\d+)'):
+        (lambda self, ics: setattr(self, 'involuntary_cs', int(ics))),
     }
 
     def parse_results(self, lines):