Minor add utility to read expert distribution recorder output (#7134)

python/sglang/srt/eplb_simulator/__init__.py

+from . import reader

python/sglang/srt/eplb_simulator/reader.py

+from collections import defaultdict
+from pathlib import Path
+
+import torch
+from tqdm import tqdm
+
+from sglang.srt.managers.expert_distribution import (
+    _convert_global_physical_count_to_logical_count,
+)
+
+convert_global_physical_count_to_logical_count = (
+    _convert_global_physical_count_to_logical_count
+)
+
+
+def read_mode_per_pass(dir_data: Path):
+    """Read data from ExpertDistributionRecorder when recorded with mode `per_pass`"""
+
+    # gpc := global_physical_count
+    gpc_of_forward_pass_and_rank = defaultdict(lambda: defaultdict())
+    for path in tqdm(list(dir_data.glob("*.pt"))):
+        data_pack = torch.load(path, weights_only=True)
+        last_physical_to_logical_map = data_pack["last_physical_to_logical_map"]
+        for record in data_pack["records"]:
+            forward_pass_id = record["forward_pass_id"]
+            rank = record["rank"]
+            assert (
+                gpc_of_forward_pass_and_rank[forward_pass_id].get(rank) is None
+            ), f"Duplicated {forward_pass_id=} {rank=}"
+            gpc_of_forward_pass_and_rank[forward_pass_id][rank] = record[
+                "global_physical_count"
+            ]
+
+    forward_pass_ids = sorted(gpc_of_forward_pass_and_rank.keys())
+    print(f"Make {forward_pass_ids=} into array")
+
+    items = []
+    for forward_pass_id, gpc_of_rank in sorted(gpc_of_forward_pass_and_rank.items()):
+        gpc_of_rank_tensor = torch.stack(
+            [gpc for rank, gpc in sorted(gpc_of_rank.items())]
+        ).sum(dim=0)
+        items.append(gpc_of_rank_tensor)
+
+    gpc_of_forward_pass = torch.stack(items)
+    print(f"{gpc_of_forward_pass.shape=}")
+
+    return dict(
+        global_physical_count_of_forward_pass=gpc_of_forward_pass,
+        last_physical_to_logical_map=last_physical_to_logical_map,
+        forward_pass_ids=forward_pass_ids,
+    )