Microsoft Issues 2 patches for Windows 7 PC's & Server 2008 R2 running Bulldozer CPU
An new AMD blog details the scheduler updates that OS'es have published to support more optimized threading when running on AMD's new Bulldozer archtecture products, including Windows 7:
One of the updates is now available through Microsoft Update and will be automatically deliver, presuming you're not a dirty, dirty pirate. Dirty. The other is a hotfix available by request, which disables core parking. This update increases performance of lightly threaded applications at the expense of power saving - disabling core parking.
Core parking is performed by Bulldozer architecture CPU's to reduce power by running threads in as few modules as possible. For lightly threaded applications, this can reduce performance as non-common tasks are running the same module which can introduce latency as shared elements are contested. By disabling core parking, threads are assigned to empty modules to get the full benefit of the CPU resources, but at the expense of power saving - previously unused modules are now used, and won't go into C6 sleep to save heat and power.
Read the full AMD blog here for more information and the download links.
Let’s take a first look at Windows®. Currently, the CPU scheduling techniques used by Windows Server 2008 R2 SP1 are not optimized for the module architecture of the AMD Opteron 6200 and 4200 Series processors. This means that certain multi-threaded workloads will not be optimally distributed between cores, which can result in decreased system performance.
Microsoft has just posted a hotfix for Windows Server 2008 R2 SP1 documented in KB2645595 that enlightens the OS kernel to the AMD Opteron 6200 and 4200 Series topology so that the kernel can do a better job of scheduling threads to the processor cores. This patch leverages work that AMD and Microsoft have done cooperatively for future versions of the Windows kernel, and can be applied as desired by users running Windows Server 2008 R2 SP1. Below you’ll find links to the patches:
What are the performance gains that can be expected from this patch? It depends. Workloads that are moderately threaded have the potential for uplift. This could include virtualization, database, or transactional environments that are “bursty” – a mixture of light and heavy transactions, or legacy applications that are by nature not very threaded. The more heavily threaded the application, the less the likely the uplift. We recommend that interested users apply the patch to a test system and see how their workload responds.
One of the updates is now available through Microsoft Update and will be automatically deliver, presuming you're not a dirty, dirty pirate. Dirty. The other is a hotfix available by request, which disables core parking. This update increases performance of lightly threaded applications at the expense of power saving - disabling core parking.
Core parking is performed by Bulldozer architecture CPU's to reduce power by running threads in as few modules as possible. For lightly threaded applications, this can reduce performance as non-common tasks are running the same module which can introduce latency as shared elements are contested. By disabling core parking, threads are assigned to empty modules to get the full benefit of the CPU resources, but at the expense of power saving - previously unused modules are now used, and won't go into C6 sleep to save heat and power.
Read the full AMD blog here for more information and the download links.
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