diff --git a/speechx/speechx/common/frontend/feature_cache.cc b/speechx/speechx/common/frontend/feature_cache.cc
index bf76aaff4..d39391d05 100644
--- a/speechx/speechx/common/frontend/feature_cache.cc
+++ b/speechx/speechx/common/frontend/feature_cache.cc
@@ -45,21 +45,11 @@ bool FeatureCache::Read(std::vector<kaldi::BaseFloat>* feats) {
         } while (result);
     }
 
-    //while (cache_.empty() && base_extractor_->IsFinished() == false) {
-        //// todo refactor: wait
-        //// ready_read_condition_.wait(lock);
-        //int32 elapsed = static_cast<int32>(timer.Elapsed() * 1000);  // ms
-        //if (elapsed > timeout_) {
-            //return false;
-        //}
-        //usleep(100);  // sleep 0.1 ms
-    //}
     if (cache_.empty()) return false;
 
     // read from cache
     *feats = cache_.front();
     cache_.pop();
-    //ready_feed_condition_.notify_one();
     VLOG(1) << "FeatureCache::Read cost: " << timer.Elapsed() << " sec.";
     return true;
 }
@@ -81,16 +71,9 @@ bool FeatureCache::Compute() {
         vector<BaseFloat> feature_chunk(feature.data() + start, 
                                         feature.data() + start + dim_);
 
-       // std::unique_lock<std::mutex> lock(mutex_);
-        //while (cache_.size() >= max_size_) {
-            // cache full, wait
-         //   ready_feed_condition_.wait(lock);
-        //}
-
         // feed cache
         cache_.push(feature_chunk);
         ++nframe_;
-        //ready_read_condition_.notify_one();
     }
 
     VLOG(1) << "FeatureCache::Compute cost: " << timer.Elapsed() << " sec. "