exo_bench: --skip-instance-setup flag and remove existing instances before instance creation

bench/exo_bench.py

@@ -370,6 +370,11 @@ def main() -> int:
     ap.add_argument(
         "--dry-run", action="store_true", help="List selected placements and exit."
     )
+    ap.add_argument(
+        "--skip-instance-setup",
+        action="store_true",
+        help="Skip planning/download/placement (assumes model instance is already running).",
+    )
     ap.add_argument(
         "--all-combinations",
         action="store_true",
@@ -440,81 +445,110 @@ def main() -> int:
         logger.error("[exo-bench] tokenizer usable but prompt sizing failed")
         raise
 
-    selected = settle_and_fetch_placements(
-        client, full_model_id, args, settle_timeout=args.settle_timeout
-    )
-
-    if not selected:
-        logger.error("No valid placements matched your filters.")
-        return 1
-
-    selected.sort(
-        key=lambda p: (
-            str(p.get("instance_meta", "")),
-            str(p.get("sharding", "")),
-            nodes_used_in_instance(p["instance"]),
-        ),
-        reverse=True,
-    )
-
-    logger.debug(f"exo-bench model: short_id={short_id} full_id={full_model_id}")
-    logger.info(f"placements: {len(selected)}")
-    for p in selected:
-        logger.info(
-            f"  - {p['sharding']} / {p['instance_meta']} / nodes={nodes_used_in_instance(p['instance'])}"
+    if args.skip_instance_setup:
+        selected = []
+        download_duration_s = None
+        logger.info("Skipping instance setup — assuming model is already running")
+    else:
+        selected = settle_and_fetch_placements(
+            client, full_model_id, args, settle_timeout=args.settle_timeout
         )
 
-    if args.dry_run:
-        return 0
+        if not selected:
+            logger.error("No valid placements matched your filters.")
+            return 1
 
-    settle_deadline = (
-        time.monotonic() + args.settle_timeout if args.settle_timeout > 0 else None
-    )
+        selected.sort(
+            key=lambda p: (
+                str(p.get("instance_meta", "")),
+                str(p.get("sharding", "")),
+                nodes_used_in_instance(p["instance"]),
+            ),
+            reverse=True,
+        )
 
-    logger.info("Planning phase: checking downloads...")
-    download_duration_s = run_planning_phase(
-        client,
-        full_model_id,
-        selected[0],
-        args.danger_delete_downloads,
-        args.timeout,
-        settle_deadline,
-    )
-    if download_duration_s is not None:
-        logger.info(f"Download: {download_duration_s:.1f}s (freshly downloaded)")
-    else:
-        logger.info("Download: model already cached")
+        logger.debug(f"exo-bench model: short_id={short_id} full_id={full_model_id}")
+        logger.info(f"placements: {len(selected)}")
+        for p in selected:
+            logger.info(
+                f"  - {p['sharding']} / {p['instance_meta']} / nodes={nodes_used_in_instance(p['instance'])}"
+            )
 
-    cluster_snapshot = capture_cluster_snapshot(client)
+        if args.dry_run:
+            return 0
+
+        settle_deadline = (
+            time.monotonic() + args.settle_timeout if args.settle_timeout > 0 else None
+        )
+
+        logger.info("Planning phase: checking downloads...")
+        download_duration_s = run_planning_phase(
+            client,
+            full_model_id,
+            selected[0],
+            args.danger_delete_downloads,
+            args.timeout,
+            settle_deadline,
+        )
+        if download_duration_s is not None:
+            logger.info(f"Download: {download_duration_s:.1f}s (freshly downloaded)")
+        else:
+            logger.info("Download: model already cached")
+
+    cluster_snapshot = capture_cluster_snapshot(client) if not args.skip_instance_setup else {}
     all_rows: list[dict[str, Any]] = []
     all_system_metrics: dict[str, dict[str, dict[str, float]]] = {}
 
+    if args.skip_instance_setup:
+        # Run benchmark directly without instance management
+        selected = [None]  # Single iteration, no placement info
+
     for preview in selected:
-        instance = preview["instance"]
-        instance_id = instance_id_from_instance(instance)
+        if preview is not None:
+            instance = preview["instance"]
+            instance_id = instance_id_from_instance(instance)
 
-        sharding = str(preview["sharding"])
-        instance_meta = str(preview["instance_meta"])
-        n_nodes = nodes_used_in_instance(instance)
+            sharding = str(preview["sharding"])
+            instance_meta = str(preview["instance_meta"])
+            n_nodes = nodes_used_in_instance(instance)
 
-        logger.info("=" * 80)
-        logger.info(
-            f"PLACEMENT: {sharding} / {instance_meta} / nodes={n_nodes} / instance_id={instance_id}"
-        )
+            logger.info("=" * 80)
+            logger.info(
+                f"PLACEMENT: {sharding} / {instance_meta} / nodes={n_nodes} / instance_id={instance_id}"
+            )
 
-        client.request_json("POST", "/instance", body={"instance": instance})
-        try:
-            wait_for_instance_ready(client, instance_id)
-        except (RuntimeError, TimeoutError) as e:
-            logger.error(f"Failed to initialize placement: {e}")
-            with contextlib.suppress(ExoHttpError):
-                client.request_json("DELETE", f"/instance/{instance_id}")
-            continue
+            # Delete any existing instances to free resources before placing
+            try:
+                state = client.request_json("GET", "/state")
+                for old_id in list(state.get("instances", {}).keys()):
+                    logger.info(f"Deleting stale instance {old_id}")
+                    with contextlib.suppress(ExoHttpError):
+                        client.request_json("DELETE", f"/instance/{old_id}")
+                if state.get("instances"):
+                    time.sleep(2)
+            except Exception:
+                pass
 
-        time.sleep(1)
+            client.request_json("POST", "/instance", body={"instance": instance})
+            try:
+                wait_for_instance_ready(client, instance_id)
+            except (RuntimeError, TimeoutError) as e:
+                logger.error(f"Failed to initialize placement: {e}")
+                with contextlib.suppress(ExoHttpError):
+                    client.request_json("DELETE", f"/instance/{instance_id}")
+                continue
+
+            time.sleep(1)
+        else:
+            instance_id = None
+            sharding = "unknown"
+            instance_meta = "unknown"
+            n_nodes = 0
+            logger.info("=" * 80)
+            logger.info("SKIP-INSTANCE-SETUP: using existing running instance")
 
         sampler: SystemMetricsSampler | None = None
-        if not args.no_system_metrics:
+        if not args.no_system_metrics and preview is not None:
             nids = node_ids_from_instance(instance)
             sampler = SystemMetricsSampler(
                 ExoClient(args.host, args.port, timeout_s=30),
@@ -737,15 +771,16 @@ def main() -> int:
                 if placement_metrics:
                     all_system_metrics.update(placement_metrics)
 
-            try:
-                client.request_json("DELETE", f"/instance/{instance_id}")
-            except ExoHttpError as e:
-                if e.status != 404:
-                    raise
-            wait_for_instance_gone(client, instance_id)
-            logger.debug(f"Deleted instance {instance_id}")
+            if instance_id is not None:
+                try:
+                    client.request_json("DELETE", f"/instance/{instance_id}")
+                except ExoHttpError as e:
+                    if e.status != 404:
+                        raise
+                wait_for_instance_gone(client, instance_id)
+                logger.debug(f"Deleted instance {instance_id}")
 
-            time.sleep(5)
+                time.sleep(5)
 
     output: dict[str, Any] = {"runs": all_rows}
     if cluster_snapshot: