Ignore execution_time regressions when binaries have same hash

.gitignore

@@ -10,3 +10,4 @@ lnt/server/ui/static/docs
 test_run_tmp
 tests/**/Output
 venv
+*~

lnt/server/db/migrations/upgrade_17_to_18.py

@@ -0,0 +1,26 @@
+"""Adds a ignore_same_hash column to the sample fields table and sets it to
+true for execution_time.
+
+"""
+
+from sqlalchemy import Column, Integer, update
+
+from lnt.server.db.migrations.util import introspect_table
+from lnt.server.db.util import add_column
+
+
+def upgrade(engine):
+    ignore_same_hash = Column("ignore_same_hash", Integer, default=0)
+    add_column(engine, "TestSuiteSampleFields", ignore_same_hash)
+
+    test_suite_sample_fields = introspect_table(engine, "TestSuiteSampleFields")
+    set_init_value = update(test_suite_sample_fields).values(ignore_same_hash=0)
+    set_exec_time = (
+        update(test_suite_sample_fields)
+        .where(test_suite_sample_fields.c.Name == "execution_time")
+        .values(ignore_same_hash=1)
+    )
+
+    with engine.begin() as trans:
+        trans.execute(set_init_value)
+        trans.execute(set_exec_time)

lnt/server/db/testsuite.py

@@ -173,6 +173,7 @@ def from_json(data):
         for index, metric_desc in enumerate(data['metrics']):
             name = metric_desc['name']
             bigger_is_better = metric_desc.get('bigger_is_better', False)
+            ignore_same_hash = metric_desc.get('ignore_same_hash', False)
             metric_type_name = metric_desc.get('type', 'Real')
             display_name = metric_desc.get('display_name')
             unit = metric_desc.get('unit')
@@ -182,8 +183,10 @@ def from_json(data):
                                  metric_type_name)
             metric_type = SampleType(metric_type_name)
             bigger_is_better_int = 1 if bigger_is_better else 0
+            ignore_same_hash_int = 1 if ignore_same_hash else 0
             field = SampleField(name, metric_type, index, status_field=None,
                                 bigger_is_better=bigger_is_better_int,
+                                ignore_same_hash=ignore_same_hash_int,
                                 display_name=display_name, unit=unit,
                                 unit_abbrev=unit_abbrev)
             sample_fields.append(field)
@@ -196,6 +199,7 @@ def __json__(self):
         for sample_field in self.sample_fields:
             metric = {
                 'bigger_is_better': (sample_field.bigger_is_better != 0),
+                'ignore_same_hash': (sample_field.ignore_same_hash != 0),
                 'display_name': sample_field.display_name,
                 'name': sample_field.name,
                 'type': sample_field.type.name,
@@ -340,12 +344,18 @@ class SampleField(FieldMixin, Base):
     # This assumption can be inverted by setting this column to nonzero.
     bigger_is_better = Column("bigger_is_better", Integer)
 
+    # Some fields like execution_time should ignore changes if the binary hash
+    # is the same.
+    ignore_same_hash = Column("ignore_same_hash", Integer, default=0)
+
     def __init__(self, name, type, schema_index, status_field=None, bigger_is_better=0,
+                 ignore_same_hash=0,
                  display_name=None, unit=None, unit_abbrev=None):
         self.name = name
         self.type = type
         self.status_field = status_field
         self.bigger_is_better = bigger_is_better
+        self.ignore_same_hash = ignore_same_hash
         self.display_name = name if display_name is None else display_name
         self.unit = unit
         self.unit_abbrev = unit_abbrev
@@ -367,7 +377,7 @@ def __repr__(self):
 
     def __copy__(self):
         return SampleField(self.name, self.type, self.schema_index, self.status_field,
-                           self.bigger_is_better, self.display_name, self.unit,
+                           self.bigger_is_better, self.ignore_same_hash, self.display_name, self.unit,
                            self.unit_abbrev)
 
     def copy_info(self, other):

lnt/server/reporting/analysis.py

@@ -54,7 +54,8 @@ class ComparisonResult:
     def __init__(self, aggregation_fn,
                  cur_failed, prev_failed, samples, prev_samples,
                  cur_hash, prev_hash, cur_profile=None, prev_profile=None,
-                 confidence_lv=0.05, bigger_is_better=False):
+                 confidence_lv=0.05, bigger_is_better=False,
+                 ignore_same_hash=False):
         self.aggregation_fn = aggregation_fn
 
         # Special case: if we're using the minimum to aggregate, swap it for
@@ -103,6 +104,7 @@ def __init__(self, aggregation_fn,
 
         self.confidence_lv = confidence_lv
         self.bigger_is_better = bigger_is_better
+        self.ignore_same_hash = ignore_same_hash
 
     def __repr__(self):
         """Print this ComparisonResult's constructor.
@@ -118,7 +120,8 @@ def __repr__(self):
                           self.samples,
                           self.prev_samples,
                           self.confidence_lv,
-                          bool(self.bigger_is_better))
+                          bool(self.bigger_is_better),
+                          bool(self.ignore_same_hash))
 
     def __json__(self):
         simple_dict = self.__dict__
@@ -176,6 +179,12 @@ def get_value_status(self, confidence_interval=2.576,
         elif self.prev_failed:
             return UNCHANGED_PASS
 
+        # Ignore changes if the hash of the binary is the same and the field is
+        # sensitive to the hash, e.g. execution time.
+        if self.ignore_same_hash:
+            if self.cur_hash and self.prev_hash and self.cur_hash == self.prev_hash:
+                return UNCHANGED_PASS
+
         # Always ignore percentage changes below MIN_PERCENTAGE_CHANGE %, for now, we just don't
         # have enough time to investigate that level of stuff.
         if ignore_small and abs(self.pct_delta) < MIN_PERCENTAGE_CHANGE:
@@ -355,7 +364,8 @@ def get_comparison_result(self, runs, compare_runs, test_id, field,
                              prev_values, cur_hash, prev_hash,
                              cur_profile, prev_profile,
                              self.confidence_lv,
-                             bigger_is_better=field.bigger_is_better)
+                             bigger_is_better=field.bigger_is_better,
+                             ignore_same_hash=field.ignore_same_hash)
         return r
 
     def get_geomean_comparison_result(self, run, compare_to, field, tests):
@@ -385,7 +395,8 @@ def get_geomean_comparison_result(self, run, compare_to, field, tests):
                                 cur_hash=cur_hash,
                                 prev_hash=prev_hash,
                                 confidence_lv=0,
-                                bigger_is_better=field.bigger_is_better)
+                                bigger_is_better=field.bigger_is_better,
+                                ignore_same_hash=field.ignore_same_hash)
 
     def _load_samples_for_runs(self, session, run_ids, only_tests):
         # Find the set of new runs to load.

schemas/nts.yaml

@@ -16,6 +16,7 @@ metrics:
   display_name: Execution Time
   unit: seconds
   unit_abbrev: s
+  ignore_same_hash: true
 - name: execution_status
   type: Status
 - name: score

tests/server/reporting/analysis.py

@@ -319,6 +319,28 @@ def test_handle_zero_sample(self):
                 None, None)
             self.assertEqual(zeroSample.get_value_status(), UNCHANGED_PASS)
 
+    def test_ignore_same_hash(self):
+        """Test ignore_same_hash ignores regressions with the same hash."""
+        same_hash = ComparisonResult(min, False, False, [10.], [5.],
+                                     'abc', 'abc', ignore_same_hash=True)
+        self.assertEqual(same_hash.get_value_status(), UNCHANGED_PASS)
+        self.assertFalse(same_hash.is_result_interesting())
+
+        diff_hash = ComparisonResult(min, False, False, [10.], [5.],
+                                     'abc', '123', ignore_same_hash=True)
+        self.assertEqual(diff_hash.get_value_status(), REGRESSED)
+        self.assertTrue(diff_hash.is_result_interesting())
+
+        no_hash = ComparisonResult(min, False, False, [10.], [5.], None,
+                                   '123', ignore_same_hash=True)
+        self.assertEqual(no_hash.get_value_status(), REGRESSED)
+        self.assertTrue(no_hash.is_result_interesting())
+
+        disabled = ComparisonResult(min, False, False, [10.], [5.],
+                                    'abc', 'abc', ignore_same_hash=False)
+        self.assertEqual(disabled.get_value_status(), REGRESSED)
+        self.assertTrue(disabled.is_result_interesting())
+
 
 class AbsMinTester(unittest.TestCase):
 

tests/server/ui/test_api.py

@@ -290,6 +290,8 @@ def test_schema(self):
                     m['display_name'] = m['name']
                 if 'bigger_is_better' not in m:
                     m['bigger_is_better'] = False
+                if 'ignore_same_hash' not in m:
+                    m['ignore_same_hash'] = False
             yaml_schema['metrics'].sort(key=lambda x: x['name'])
             yaml_schema['run_fields'].sort(key=lambda x: x['name'])
             yaml_schema['machine_fields'].sort(key=lambda x: x['name'])