HP ProLiant DL380p ISS Technology Focus, Number 14 - Page 4

power to DC. The severity of the power loss depends on the equipment. DC power distribution improves safety, minimizes electrical losses, and improves data center efficiency. As shown in the previous figure, DC power is isolated from the 480 V AC supplied by the utility. This is much safer for personnel servicing equipment because arc flash is not a concern. DC power distribution also requires fewer conversions from the utility to the server components, which increases efficiency. DC and AC power supplies For several years, -48 V DC power supplies were more efficient than AC power supplies. But today‟s AC power supplies, such as the HP Gold and Platinum Common Slot Power Supplies, achieve efficiencies that reach or exceed 90%. In particular, HP Platinum Common Slot Power Supplies reach 94% efficiency at 50% load. So, the power efficiency advantage has now gone to AC power supplies. Tip: Check Hyper-Threading status remotely using Microsoft® Windows® PowerShell Intel® Xeon® four-core processors based on the Intel Microarchitecture Nehalem reintroduced support for Hyper-Threading (HT) Technology, also known as simultaneous multi-threading. HT, which is enabled by default, allows the OS to schedule two instruction threads to each core to share its physical resources. HT can boost the performance of some workloads, such as Internet and e-commerce applications, by as much as 30%. But HT can also decrease the performance of applications, such as HPC, that have high thread contention for the core‟s resources. For this reason, you may have disabled HT Technology on some servers through the ROM Based Setup Utility (RBSU). But in environments with hundreds or thousands of servers, it‟s difficult to remotely determine which servers are HT-disabled. The most common options are: • Reboot each server and check the HT status through the RBSU • Log in to the remote console of each server and check its Task Manager. Both options are time-consuming. A better way to check if HT is disabled for processors running Windows Server 2008 or Windows Vista® is to use Windows PowerShell. PowerShell is a task automation framework. It consists of a command-line shell and associated scripting language built on top of the .NET Framework. PowerShell provides full access to Windows Management Instrumentation (WMI), enabling administrators to perform tasks on local and remote servers. PowerShell scripting lets administrators automate queries to remote servers using a comma-separated list of computer names. To query a remote computer about the HT status of its processors, use the Win32_Processor association class: Get-WmiObject Win32_Processor; add -computername whatever (replace whatever with a comma-separated list of computer names) Each instance of Win32_Processor is a socket with properties that include NumberOfLogicalProcessors and NumberOfCores. The NumberOfCores value represents the number of cores for the current instance of the processor. If HT is enabled in the BIOS for the processor, then NumberOfCores is less than NumberOfLogicalProcessors. To determine the total number of processor instances associated with a computer system object, use the Win32_ComputerSystemProcessor association class. Additional resources » Microsoft Windows PowerShell » Win32_Processor class