From 83d500bac9c375221120b4ae09e0e3cbd55f96b1 Mon Sep 17 00:00:00 2001
From: mateo-berri <277851410+mateo-berri@users.noreply.github.com>
Date: Mon, 7 Sep 2026 21:29:26 -0700
Subject: [PATCH] fix(router): count deployment itpm reservations off the event
 loop

---
 litellm/litellm_core_utils/token_counter.py   |  4 +--
 .../io_token_rate_limit_check.py              |  3 +-
 .../test_router/test_io_token_rate_limits.py  | 28 +++++++++++++++++++
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/litellm/litellm_core_utils/token_counter.py b/litellm/litellm_core_utils/token_counter.py
index e3a0d4c785a..e3af64fd3bf 100644
--- a/litellm/litellm_core_utils/token_counter.py
+++ b/litellm/litellm_core_utils/token_counter.py
@@ -315,12 +315,12 @@ def calculate_img_tokens(
 
 
 TokenCounterFunction = Callable[[str], int]
-
-EXTRAPOLATION_SAMPLES: Final = 16
 """
 Type for a function that counts tokens in a string.
 """
 
+EXTRAPOLATION_SAMPLES: Final = 16
+
 
 def _get_tiktoken_count_function(
     encode_length: Callable[[str], int],
diff --git a/litellm/router_utils/pre_call_checks/io_token_rate_limit_check.py b/litellm/router_utils/pre_call_checks/io_token_rate_limit_check.py
index 01d42627001..dca5a2be845 100644
--- a/litellm/router_utils/pre_call_checks/io_token_rate_limit_check.py
+++ b/litellm/router_utils/pre_call_checks/io_token_rate_limit_check.py
@@ -21,6 +21,7 @@ import litellm
 from litellm import token_counter
 from litellm._logging import verbose_router_logger
 from litellm.caching.dual_cache import DualCache
+from litellm.litellm_core_utils.asyncify import asyncify
 from litellm.types.router import RouterCacheEnum, RouterErrors
 from litellm.utils import get_utc_datetime
 
@@ -466,7 +467,7 @@ async def async_io_token_pre_call_check(
 
     request_kwargs: Final = get_io_token_rate_limit_request_kwargs()
     _model: Final = (deployment.get("litellm_params") or {}).get("model") or ""
-    estimated_input: Final = _estimate_input_tokens(request_kwargs, model=_model)
+    estimated_input: Final = await asyncify(_estimate_input_tokens)(request_kwargs, model=_model)
     max_tokens: Final = _resolve_max_tokens(request_kwargs, deployment)
 
     dt: Final = get_utc_datetime()
diff --git a/tests/test_litellm/test_router/test_io_token_rate_limits.py b/tests/test_litellm/test_router/test_io_token_rate_limits.py
index a5a68271111..3cef1c7bb63 100644
--- a/tests/test_litellm/test_router/test_io_token_rate_limits.py
+++ b/tests/test_litellm/test_router/test_io_token_rate_limits.py
@@ -1039,3 +1039,31 @@ class TestContextSlotRetention:
         assert deployment is not None
         router._update_kwargs_with_deployment(deployment=deployment.model_dump(), kwargs=kwargs)
         assert get_io_token_rate_limit_request_kwargs() is kwargs
+
+
+@pytest.mark.asyncio
+async def test_the_deployment_itpm_reservation_counts_the_request_off_the_event_loop():
+    from litellm.utils import get_utc_datetime
+    from tests.large_text import text
+    from tests.test_litellm.litellm_core_utils.event_loop_lag import (
+        assert_loop_stayed_free,
+        timed_with_loop_lags,
+        warm_tokenizer,
+    )
+
+    dual_cache = DualCache()
+    check = ModelRateLimitingCheck(dual_cache=dual_cache)
+    warm_tokenizer("anthropic/claude-fable-5")
+    deployment = {
+        "litellm_params": {"model": "anthropic/claude-fable-5", "itpm": 10_000_000},
+        "model_info": {"id": "io-loop-id"},
+        "model_name": "claude",
+    }
+    set_io_token_rate_limit_request_kwargs({"messages": [{"role": "user", "content": text * 100}], "metadata": {}})
+
+    _, took, lags = await timed_with_loop_lags(lambda: check.async_pre_call_check(deployment))
+
+    minute = get_utc_datetime().strftime("%H-%M")
+    reserved = await dual_cache.async_get_cache(key=f"global_router:io-loop-id:anthropic/claude-fable-5:itpm:{minute}")
+    assert reserved > 100_000
+    assert_loop_stayed_free(took, lags)