expose batchcontextpool settings

src/csharp/Grpc.Core/GrpcEnvironment.cs

@@ -33,6 +33,8 @@ namespace Grpc.Core
     public class GrpcEnvironment
     {
         const int MinDefaultThreadPoolSize = 4;
+        const int DefaultBatchContextPoolSharedCapacity = 10000;
+        const int DefaultBatchContextPoolThreadLocalCapacity = 64;
 
         static object staticLock = new object();
         static GrpcEnvironment instance;
@@ -40,6 +42,8 @@ namespace Grpc.Core
         static int? customThreadPoolSize;
         static int? customCompletionQueueCount;
         static bool inlineHandlers;
+        static int batchContextPoolSharedCapacity = DefaultBatchContextPoolSharedCapacity;
+        static int batchContextPoolThreadLocalCapacity = DefaultBatchContextPoolThreadLocalCapacity;
         static readonly HashSet<Channel> registeredChannels = new HashSet<Channel>();
         static readonly HashSet<Server> registeredServers = new HashSet<Server>();
 
@@ -187,7 +191,7 @@ namespace Grpc.Core
 
         /// <summary>
         /// Sets the number of threads in the gRPC thread pool that polls for internal RPC events.
-        /// Can be only invoke before the <c>GrpcEnviroment</c> is started and cannot be changed afterwards.
+        /// Can be only invoked before the <c>GrpcEnviroment</c> is started and cannot be changed afterwards.
         /// Setting thread pool size is an advanced setting and you should only use it if you know what you are doing.
         /// Most users should rely on the default value provided by gRPC library.
         /// Note: this method is part of an experimental API that can change or be removed without any prior notice.
@@ -204,7 +208,7 @@ namespace Grpc.Core
 
         /// <summary>
         /// Sets the number of completion queues in the  gRPC thread pool that polls for internal RPC events.
-        /// Can be only invoke before the <c>GrpcEnviroment</c> is started and cannot be changed afterwards.
+        /// Can be only invoked before the <c>GrpcEnviroment</c> is started and cannot be changed afterwards.
         /// Setting the number of completions queues is an advanced setting and you should only use it if you know what you are doing.
         /// Most users should rely on the default value provided by gRPC library.
         /// Note: this method is part of an experimental API that can change or be removed without any prior notice.
@@ -238,6 +242,26 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Sets the parameters for a pool that caches batch context instances. Reusing batch context instances
+        /// instead of creating a new one for every C core operation helps reducing the GC pressure.
+        /// Can be only invoked before the <c>GrpcEnviroment</c> is started and cannot be changed afterwards.
+        /// This is an advanced setting and you should only use it if you know what you are doing.
+        /// Most users should rely on the default value provided by gRPC library.
+        /// Note: this method is part of an experimental API that can change or be removed without any prior notice.
+        /// </summary>
+        public static void SetBatchContextPoolParams(int sharedCapacity, int threadLocalCapacity)
+        {
+            lock (staticLock)
+            {
+                GrpcPreconditions.CheckState(instance == null, "Can only be set before GrpcEnvironment is initialized");
+                GrpcPreconditions.CheckArgument(sharedCapacity >= 0, "Shared capacity needs to be a non-negative number");
+                GrpcPreconditions.CheckArgument(threadLocalCapacity >= 0, "Thread local capacity needs to be a non-negative number");
+                batchContextPoolSharedCapacity = sharedCapacity;
+                batchContextPoolThreadLocalCapacity = threadLocalCapacity;
+            }
+        }
+
         /// <summary>
         /// Occurs when <c>GrpcEnvironment</c> is about the start the shutdown logic.
         /// If <c>GrpcEnvironment</c> is later initialized and shutdown, the event will be fired again (unless unregistered first).
@@ -250,8 +274,7 @@ namespace Grpc.Core
         private GrpcEnvironment()
         {
             GrpcNativeInit();
-            // TODO(jtattermusch): configure params
-            batchContextPool = new DefaultObjectPool<BatchContextSafeHandle>(() => BatchContextSafeHandle.Create(this.batchContextPool), 10000, 64);
+            batchContextPool = new DefaultObjectPool<BatchContextSafeHandle>(() => BatchContextSafeHandle.Create(this.batchContextPool), batchContextPoolSharedCapacity, batchContextPoolThreadLocalCapacity);
             threadPool = new GrpcThreadPool(this, GetThreadPoolSizeOrDefault(), GetCompletionQueueCountOrDefault(), inlineHandlers);
             threadPool.Start();
         }