Windows System Resource Manager (WSRM) is an optional component that is available in Windows Server 2008 R2. WSRM supports an “equal per session” built-in policy that keeps CPU usage equally distributed among all active sessions on the system. Although enabling WSRM adds some CPU usage overhead to the system, we recommend that you enable it because it helps limit the effect that high CPU usage in one session has on the other sessions on the system. This helps improve user experience and also lets you run more users on the system because of a reduced need for a large cushion in CPU capacity to accommodate random CPU usage spikes.
This section describes the performance-related parameters that help improve the performance of a customer deployment and the tunings that rely on their network usage patterns. At its core, the Remote Desktop Gateway (RD Gateway) performs many packet forwarding operations between the Remote Desktop Connection Client instances and the RD Session Host Server instances within the customer’s network. IIS and RD Gateway export the following registry parameters to help improve system performance in the RD Gateway role:
HKLM\Software\Microsoft\Terminal Server Gateway\ (REG_DWORD)
The default value is 5. It specifies the number of threads that the RDGateway service creates to handle incoming requests.
The default value is 4. It specifies the number of Internet Information Services (IIS) pool threads to create per processor. The IIS pool threads watch the network for requests and process all incoming requests. The MaxPoolThreads count does not include threads that the RD Gateway service consumes.
The following parameters can help tune the remote procedure call (RPC) receive windows on the RDC Client and RD Gateway machines. Changing the windows helps throttle how much data is flowing through each connection and can improve performance for RPC over HTTP v2 scenarios:
The default value is 64 KB. This value specifies the receive window that the server uses for data that is received from the RPC proxy. The minimum value is set to 8 KB, and the maximum value is set at 1 GB. If the value is not present, then the default value is used. When changes are made to this value, IIS must be restarted for the change to take effect.
The default value is 64 KB. This value specifies the receive window that the client uses for data that is received from the RPC proxy. The minimum valid value is 8 KB, and the maximum value is 1 GB. If the value is not present, then the default value is used.
Hyper-V™ is the virtualization server role in Windows Server 2008 R2. Virtualization servers can host multiple virtual machines (VMs) that are isolated from each other but share the underlying hardware resources by virtualizing the processors, memory, and I/O devices. By consolidating servers onto a single machine, virtualization can improve resource usage and energy efficiency and reduce the operational and maintenance costs of servers. In addition, VMs and the management APIs offer more flexibility for managing resources, balancing load, and provisioning systems.
The following sections define the virtualization terminology that is used in this guide and suggest best practices that yield increased performance on Hyper-V servers.
This section summarizes key terminology specific to VM technology that is used throughout this performance tuning guide:
Any partition (VM) that is created by the root partition.
A mechanism that lets a hardware resource be abstracted and shared among multiple consumers.
A virtualized device that mimics an actual physical hardware device so that guests can use the typical drivers for that hardware device.
An optimization to a guest operating system to make it aware of VM environments and tune its behavior for VMs.
Software that is running in a partition. It can be a full-featured operating system or a small, special-purpose kernel. The hypervisor is “guest-agnostic.”
A layer of software that sits just above the hardware and below one or more operating systems. Its primary job is to provide isolated execution environments called partitions. Each partition has its own set of hardware resources (CPU, memory, and devices). The hypervisor is responsible for controls and arbitrates access to the underlying hardware.
logical processor (LP)
A processing unit that handles one thread of execution (instruction stream). There can be one or more logical processors per core and one or more cores per processor socket.
A representation of an entire physical disk as a virtual disk within the guest. The data and commands are “passed through” to the physical disk (through the root partition’s native storage stack) with no intervening processing by the virtual stack.
A partition that is created first and owns all the resources that the hypervisor does not, including most devices and system memory. It hosts the virtualization stack and creates and manages the child partitions.
A virtualized device with no physical hardware analog so that guests might need a driver (virtualization service client) to that synthetic device. The driver can use VMBus to communicate with the virtualized device software in the root partition.
virtual machine (VM)
A virtual computer that was created by software emulation and has the same characteristics as a real computer.
virtual processor (VP)
A virtual abstraction of a processor that is scheduled to run on a logical processor. A VM can have one or more virtual processors.
virtualization service client (VSC)
A software module that a guest loads to consume a resource or service. For I/O devices, the virtualization service client can be a device driver that the operating system kernel loads.
virtualization service provider (VSP)
A provider exposed by the virtualization stack in the root partition that provides resources or services such as I/O to a child partition.
A collection of software components in the root partition that work together to support VMs. The virtualization stack works with and sits above the hypervisor. It also provides management capabilities.