40555 Rev. 3.00 June 2006

Performance Guidelines for AMD Athlon™ 64 and AMD Opteron™

 

ccNUMA Multiprocessor Systems

A.5 Why Is 0 Hop-1 Hop Case Slower Than

0 Hop-0 Hop Case on a System under High Background Load (High Subscription) for Write- Only Threads?

When a 0 hop-0 hop scenario is subjected to a very high background load, the system sees the following traffic pattern, where each node gets memory requests from the threads as described:

•Node 0: 2 foreground threads.

•Node 1: 1 background thread.

•Node 3: 1 background thread.

•Node 2: 1 background thread.

In the 0 hop-1 hop case, the system sees the following traffic pattern:

•Node 0: 1 foreground thread

•Node 1: 1 foreground and 1 background threads.

•Node 3: 1 background thread.

•Node 2: 1 background thread.

The 0 hop-1 hop case suffers from a greater load imbalance than the 0 hop-0 hop case, with node 1 suffering the worst effect of this imbalance.

Each of the background threads, as before, asks for data at a rate of 4GB/s and each of the foreground threads asks for data at a rate of 2.98 GB/s.

Data shows that there is a total memory access rate of 4.78 GB/s on node 1 and several buffer queues on node 1 are saturated and cannot absorb the data provided by the memory controller any faster.

A.6 Support for a ccNUMA-Aware Scheduler for AMD64 ccNUMA Multiprocessor Systems

Developers should ensure that the OS is properly configured to support ccNUMA. All versions of Microsoft® Windows® XP for AMD64 and Windows Server for AMD64 support ccNUMA without any configuration changes. The 32-bit versions of Windows Server 2003, Enterprise Edition and Windows Server 2003, Datacenter Edition require the /PAE boot parameter to support ccNUMA. For 64-bit Linux®, there may be separate kernels supporting ccNUMA that should be selected. The 2.6.x Linux kernels feature NUMA awareness in the scheduler[11]. Most SuSE and Red Hat Enterprise distributions of 64-bit Linux have the ccNUMA aware kernel. Solaris 10 and subsequent versions of Solaris for AMD64 support ccNUMA without any changes.

Appendix A

43

Page 42 Page 44
Page 43
Image 43
AMD 64 manual Appendix a
Page 42 Page 44

64 specifications

AMD64 is a 64-bit architecture developed by Advanced Micro Devices (AMD) as an extension of the x86 architecture. Introduced in the early 2000s, it aimed to offer enhanced performance and capabilities to powering modern computing systems. One of the main features of AMD64 is its ability to address a significantly larger amount of memory compared to its 32-bit predecessors. While the old x86 architecture was limited to 4 GB of RAM, AMD64 can theoretically support up to 16 exabytes of memory, making it ideal for applications requiring large datasets, such as scientific computing and complex simulations.

Another key characteristic of AMD64 is its support for backward compatibility. This means that it can run existing 32-bit applications seamlessly, allowing users to upgrade their hardware without losing access to their existing software libraries. This backward compatibility is achieved through a mode known as Compatibility Mode, enabling users to benefit from both newer 64-bit applications and older 32-bit applications.

AMD64 also incorporates several advanced technologies to optimize performance. One such technology is the support for multiple cores and simultaneous multithreading (SMT). This allows processors to handle multiple threads concurrently, improving overall performance, especially in multi-tasking and multi-threaded applications. With the rise of multi-core processors, AMD64 has gained traction in both consumer and enterprise markets, providing users with an efficient computing experience.

Additionally, AMD64 supports advanced vector extensions (AVX), which enhance the capability of processors to perform single instruction, multiple data (SIMD) operations. This is particularly beneficial for tasks such as video encoding, scientific simulations, and cryptography, allowing these processes to be executed much faster, thereby increasing overall throughput.

Security features are also integrated within AMD64 architecture. Technologies like AMD Secure Execution and Secure Memory Encryption help protect sensitive data and provide an enhanced security environment for virtualized systems.

In summary, AMD64 is a powerful and versatile architecture that extends the capabilities of x86, offering enhanced memory addressing, backward compatibility, multi-core processing, vector extensions, and robust security features. These innovations have positioned AMD as a strong competitor in the computing landscape, catering to the demands of modern users and applications. The continuous evolution of AMD64 technology demonstrates AMD's commitment to pushing the boundaries of computing performance and efficiency.
Top Page Image Contents