Fix issue with tallying concurrency

Signed-off-by: Samuel Monson <[email protected]>

Author: sjmonson

src/guidellm/objects/statistics.py

@@ -219,7 +219,7 @@ def from_values(
         )
 
     @staticmethod
-    def from_request_times(
+    def from_request_times(  # noqa: C901
         requests: list[tuple[float, float]],
         distribution_type: Literal["concurrency", "rate"],
         include_cdf: bool = False,
@@ -248,13 +248,7 @@ def from_request_times(
                 time_deltas[start] += 1
                 time_deltas[end] -= 1
 
-            # convert to the events over time measuring concurrency changes
-            events = []
-            active = 0
-
-            for time, delta in sorted(time_deltas.items()):
-                active += delta
-                events.append((time, active))
+            events = list(time_deltas.items())
         elif distribution_type == "rate":
             # convert to events for when requests finished
             global_start = min(start for start, _ in requests) if requests else 0
@@ -281,6 +275,16 @@ def from_request_times(
             else:
                 flattened_events.append((time, val))
 
+        if distribution_type == "concurrency":
+            # convert to the events over time measuring concurrency changes
+            events_over_time: list[tuple[float, float]] = []
+            active = 0
+            for time, delta in flattened_events:
+                active += delta  # type: ignore [assignment]
+                events_over_time.append((time, active))
+
+            flattened_events = events_over_time
+
         # convert to value distribution function
         distribution: dict[float, float] = defaultdict(float)