prefer to handle cache RPC requests synchronously (#428)

* only handle RPC requests in a worker thread if we have an upstream. we may as well handle the request inline on the http_io thread if we're only dealing with local data since the response times should be pretty consistent in that case
* http.sys: don't create async worker thread pool until it's needed (typically only if we have an upstream)

1 files changed, 22 insertions, 1 deletions

diff --git a/src/zenhttp/httpsys.cpp b/src/zenhttp/httpsys.cpp
index f95a31914..886d53143 100644
--- a/src/zenhttp/httpsys.cpp
+++ b/src/zenhttp/httpsys.cpp
@@ -747,7 +747,7 @@ HttpSysServer::HttpSysServer(const Config& Config)
 , m_IsRequestLoggingEnabled(Config.IsRequestLoggingEnabled)
 , m_IsAsyncResponseEnabled(Config.IsAsyncResponseEnabled)
 , m_ThreadPool(Config.ThreadCount != 0 ? Config.ThreadCount : std::thread::hardware_concurrency())
-, m_AsyncWorkPool(Config.AsyncWorkThreadCount != 0 ? Config.AsyncWorkThreadCount : 16, "http_async")
+, m_InitialConfig(Config)
 {
 	ULONG Result = HttpInitialize(HTTPAPI_VERSION_2, HTTP_INITIALIZE_SERVER, nullptr);
 
@@ -768,6 +768,9 @@ HttpSysServer::~HttpSysServer()
 	{
 		ZEN_ERROR("~HttpSysServer() called without calling Close() first");
 	}
+
+	delete m_AsyncWorkPool;
+	m_AsyncWorkPool = nullptr;
 }
 
 void
@@ -977,6 +980,24 @@ HttpSysServer::Cleanup()
 	}
 }
 
+WorkerThreadPool&
+HttpSysServer::WorkPool()
+{
+	if (!m_AsyncWorkPool)
+	{
+		RwLock::ExclusiveLockScope _(m_AsyncWorkPoolInitLock);
+
+		if (!m_AsyncWorkPool)
+		{
+			unsigned int WorkerThreadCount = m_InitialConfig.AsyncWorkThreadCount != 0 ? m_InitialConfig.AsyncWorkThreadCount : 16;
+
+			m_AsyncWorkPool = new WorkerThreadPool(WorkerThreadCount, "http_async");
+		}
+	}
+
+	return *m_AsyncWorkPool;
+}
+
 void
 HttpSysServer::StartServer()
 {