Log runtime for individual forward model steps

This is meant for making statistics pr forward model step name.

While testing on poly_example and local queue, there
is some odd occurences of the logged message that start_time
is None, this is not believed to happen often in production.

src/ert/ensemble_evaluator/snapshot.py

@@ -1,3 +1,4 @@
+import logging
 import sys
 import typing
 from collections import defaultdict
@@ -46,6 +47,8 @@
 from ert.ensemble_evaluator import identifiers as ids
 from ert.ensemble_evaluator import state
 
+logger = logging.getLogger(__name__)
+
 if sys.version_info < (3, 11):
     from backports.datetime_fromisoformat import MonkeyPatch  # type: ignore
 
@@ -327,6 +330,39 @@ def update_from_event(
                 start_time = convert_iso8601_to_datetime(timestamp)
             elif e_type in {ForwardModelStepSuccess, ForwardModelStepFailure}:
                 end_time = convert_iso8601_to_datetime(timestamp)
+
+                try:
+                    start_time = self._fm_step_snapshots[event.real, event.fm_step].get(
+                        "start_time"
+                    )
+                    cpu_seconds = self._fm_step_snapshots[
+                        event.real, event.fm_step
+                    ].get("cpu_seconds")
+                    fm_step_name = source_snapshot.reals[event.real]["fm_steps"][
+                        event.fm_step
+                    ]["name"]
+                    if start_time is not None:
+                        logger.warning(
+                            f"{event.event_type} {fm_step_name} "
+                            f"walltime={(end_time - start_time).total_seconds()} "
+                            f"cputime={cpu_seconds} "
+                            f"ensemble={event.ensemble} "
+                            f"step_index={event.fm_step} "
+                            f"real={event.real}"
+                        )
+                    else:
+                        logger.warning(
+                            f"Should log fm_step runtime, but start_time was None, "
+                            f"{event.event_type} {fm_step_name=} "
+                            f"endtime={end_time.isoformat()} "
+                            f"cputime={cpu_seconds} "
+                            f"ensemble={event.ensemble} "
+                            f"step_index={event.fm_step} "
+                            f"real={event.real}"
+                        )
+                except BaseException as e:
+                    logger.warning(f"Should log fm_step runtime, but got exception {e}")
+
                 if type(event) is ForwardModelStepFailure:
                     error = event.error_msg if event.error_msg else ""
                 else: