[Core][Metrics] Remove unused `SchedulerStats.encoder_cache_usage` (#39693)

Signed-off-by: Mark McLoughlin <markmc@redhat.com>

vllm/v1/core/sched/scheduler.py

@@ -1961,7 +1961,6 @@ class Scheduler(SchedulerInterface):
             num_waiting_reqs=len(self.waiting),
             num_skipped_waiting_reqs=len(self.skipped_waiting),
             kv_cache_usage=self.kv_cache_manager.usage,
-            encoder_cache_usage=self._get_encoder_cache_usage(),
             prefix_cache_stats=prefix_cache_stats,
             connector_prefix_cache_stats=connector_prefix_cache_stats,
             kv_cache_eviction_events=eviction_events,
@@ -1971,14 +1970,6 @@ class Scheduler(SchedulerInterface):
             perf_stats=perf_stats,
         )
 
-    def _get_encoder_cache_usage(self) -> float:
-        """Get encoder cache usage as a fraction (0.0 to 1.0)."""
-        ecm = self.encoder_cache_manager
-        if ecm.cache_size == 0:
-            return 0.0
-        used_slots = ecm.cache_size - ecm.num_free_slots
-        return used_slots / ecm.cache_size
-
     def make_spec_decoding_stats(
         self,
         spec_decoding_stats: SpecDecodingStats | None,

vllm/v1/metrics/stats.py

@@ -181,7 +181,6 @@ class SchedulerStats:
     current_wave: int = 0
 
     kv_cache_usage: float = 0.0
-    encoder_cache_usage: float = 0.0
 
     prefix_cache_stats: PrefixCacheStats = field(default_factory=PrefixCacheStats)
     connector_prefix_cache_stats: PrefixCacheStats | None = None