Fix issue: #254 - Fix for negative duration times.

hta/analyzers/breakdown_analysis.py

@@ -742,6 +742,21 @@ def idle_time_per_rank(trace_df: pd.DataFrame) -> Tuple[int, int, int, int]:
             ]
         ]
 
+    def _round_preserving_sum(group: pd.DataFrame) -> pd.DataFrame:
+        """Round idle time ratios while preserving the constraint
+        that they sum to 1.0 (100%) per stream."""
+
+        ratios = group["idle_time_ratio"].round(2)
+        ratio_sum = ratios.sum()
+
+        if ratio_sum != 1.0 and 0 < ratio_sum:
+            max_idx = ratios.idxmax()
+            ratios.loc[max_idx] = ratios.loc[max_idx] + (1.0 - ratio_sum)
+
+        group["idle_time_ratio"] = ratios
+
+        return group
+
     @classmethod
     def _analyze_idle_time_for_stream(
         cls,
@@ -771,6 +786,8 @@ def _analyze_idle_time_for_stream(
         gpu_kernels_s["idle_interval"] = (
             gpu_kernels_s["ts"] - gpu_kernels_s["prev_end_ts"]
         )
+        # Handle negative idle intervals that can occur due to rounding errors.
+        gpu_kernels_s.loc[gpu_kernels_s["idle_interval"] < 0, "idle_interval"] = 0
 
         # Default idle time category
         gpu_kernels_s["idle_category"] = IdleTimeType.OTHER.value
@@ -928,6 +945,8 @@ def get_idle_time_breakdown(
                 mapper=idle_category_name_map, axis=0, inplace=True
             )
 
+        grouped_result_df = result_df.groupby("stream", group_keys=False)
+        result_df = grouped_result_df.apply(cls._round_preserving_sum)
         result_df = result_df[
             ["rank", "stream", "idle_category", "idle_time", "idle_time_ratio"]
         ].round(2)

hta/analyzers/trace_counters.py

@@ -316,6 +316,8 @@ def _get_memory_bw_time_series_for_rank(
         result_df_list = []
         for _, membw_df in membw_time_series.groupby("name"):
             membw_df.memory_bw_gbps = membw_df.memory_bw_gbps.cumsum()
+            # Fix floating-point precision errors that can result in very tiny values.
+            membw_df.loc[abs(membw_df.memory_bw_gbps) < 1e-9, "memory_bw_gbps"] = 0
             result_df_list.append(membw_df)
 
         if len(result_df_list) == 0:

hta/common/trace_parser.py

@@ -386,6 +386,8 @@ def round_down_time_stamps(df: pd.DataFrame) -> None:
     df["ts"] = df[~df["ts"].isnull()]["ts"].apply(lambda x: math.ceil(x))
     df["end"] = df[~df["end"].isnull()]["end"].apply(lambda x: math.floor(x))
     df["dur"] = df["end"] - df["ts"]
+    # Fix negative durations that can occur due to rounding very small time intervals.
+    df.loc[df["dur"] < 0, "dur"] = 0
 
 
 # @profile

tests/test_trace_parse.py

@@ -649,6 +649,26 @@ def test_fix_mtia_memory_kernels(self) -> None:
         # Validate results
         pd.testing.assert_frame_equal(fixed_df, expected_df)
 
+    def test_round_down_time_stamps(self) -> None:
+        """Test that round_down_time_stamps never produces negative durations."""
+
+        # Test case 1: Very small durations that could become negative after rounding.
+        test_data = {
+            "ts": [100.3, 200.7, 300.1, 400.9],
+            "dur": [0.3, 0.2, 0.8, 0.1],
+        }
+        df = pd.DataFrame(test_data)
+        df["ts"] = df["ts"].astype("float64")
+        df["dur"] = df["dur"].astype("float64")
+
+        round_down_time_stamps(df)
+
+        # Assert no negative durations.
+        self.assertTrue(
+            (df["dur"] >= 0).all(),
+            "Found negative duration times which should not occur after rounding down timestamps!",
+        )
+
 
 class TestMetadataOnlyTrace(unittest.TestCase):
     """Test handling of traces with only metadata events (no dur/cat columns)."""