1 // Copyright 2024 gRPC authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef GRPC_SRC_CORE_LIB_TRANSPORT_CALL_SIZE_ESTIMATOR_H 16 #define GRPC_SRC_CORE_LIB_TRANSPORT_CALL_SIZE_ESTIMATOR_H 17 18 #include <grpc/support/port_platform.h> 19 20 #include <stddef.h> 21 22 #include <atomic> 23 24 namespace grpc_core { 25 26 class CallSizeEstimator { 27 public: CallSizeEstimator(size_t initial_estimate)28 explicit CallSizeEstimator(size_t initial_estimate) 29 : call_size_estimate_(initial_estimate) {} 30 CallSizeEstimate()31 size_t CallSizeEstimate() { 32 // We round up our current estimate to the NEXT value of kRoundUpSize. 33 // This ensures: 34 // 1. a consistent size allocation when our estimate is drifting slowly 35 // (which is common) - which tends to help most allocators reuse memory 36 // 2. a small amount of allowed growth over the estimate without hitting 37 // the arena size doubling case, reducing overall memory usage 38 static constexpr size_t kRoundUpSize = 256; 39 return (call_size_estimate_.load(std::memory_order_relaxed) + 40 2 * kRoundUpSize) & 41 ~(kRoundUpSize - 1); 42 } 43 44 void UpdateCallSizeEstimate(size_t size); 45 46 private: 47 std::atomic<size_t> call_size_estimate_; 48 }; 49 50 } // namespace grpc_core 51 52 #endif // GRPC_SRC_CORE_LIB_TRANSPORT_CALL_SIZE_ESTIMATOR_H 53