Tiny add more information in retract logging. (#15694)

python/sglang/srt/managers/scheduler.py

@@ -2055,13 +2055,19 @@ class Scheduler(
             return batch
 
         # Check if decode out of memory
-        if not batch.check_decode_mem(self.decode_mem_cache_buf_multiplier) or (
-            TEST_RETRACT and self.forward_ct % TEST_RETRACT_INTERVAL == 0
-        ):
+        if (
+            kv_full_retract_flag := not batch.check_decode_mem(
+                self.decode_mem_cache_buf_multiplier
+            )
+        ) or (TEST_RETRACT and self.forward_ct % TEST_RETRACT_INTERVAL == 0):
+            old_available_tokens = self.token_to_kv_pool_allocator.available_size()
             old_ratio = self.new_token_ratio
             retracted_reqs, new_token_ratio, reqs_to_abort = batch.retract_decode(
                 self.server_args, self.decode_mem_cache_buf_multiplier
             )
+            new_available_tokens = self.token_to_kv_pool_allocator.available_size()
+            new_token_gained = new_available_tokens - old_available_tokens
+
             self.num_retracted_reqs = len(retracted_reqs)
             if self.enable_metrics and (x := len(retracted_reqs)) > 0:
                 self.metrics_collector.increment_num_retracted_reqs(x)
@@ -2072,11 +2078,17 @@ class Scheduler(
                     AbortReq(abort_message=abort_reason.message, rid=req.rid), req
                 )
 
-            logger.info(
+            msg_prefix = (
                 "KV cache pool is full. Retract requests. "
-                f"#retracted_reqs: {len(retracted_reqs)}, "
-                f"#new_token_ratio: {old_ratio:.4f} -> {new_token_ratio:.4f}"
+                if kv_full_retract_flag
+                else "Testing retraction. "
             )
+            msg_details = f"#retracted_reqs: {len(retracted_reqs)}, #new_tokens_gained: {new_token_gained}"
+            if kv_full_retract_flag:
+                msg_details += (
+                    f", #new_token_ratio: {old_ratio:.4f} -> {new_token_ratio:.4f}"
+                )
+            logger.warning(msg_prefix + msg_details)
 
             for req in retracted_reqs:
                 self._add_request_to_queue(req, is_retracted=True)