40555 Rev. 3.00 June 2006

Performance Guidelines for AMD Athlon™ 64 and AMD Opteron™

 

ccNUMA Multiprocessor Systems

 

 

C0

 

 

C1

 

 

4 GV/s per direction

4 GV/s per direction

@ 2 GHz Data Rate

@ 2 GHz Data Rate

4 GV/s per direction @ 2 GHz Data Rate

HT = HyperTransport™ Technology

Figure 2. Internal Resources Associated with a Quartet Node

From the perspective of the MCT, a memory request may come from either the local core or from

another core over a coherent HyperTransport link. The former request is a local request, while the latter is a remote request. In the former case, the request could be routed from the local core to the

SRI, then to the XBar and then to the MCT. In the later case, the request is routed from the remote core over the coherent HyperTransport link to the XBar and from there to the MCT.

The MCT, the SRI and the XBar on each node all have internal buffers that are used to queue transaction packets for transmission. For additional details on the Northbridge buffer queues, refer to Section A.1 on page 39.

From a system perspective, the developer can think of the system as having three key resources that affect throughput: memory bandwidth, HyperTransport bandwidth and buffer queue capacity.

2.2Synthetic Test

The test used is a simple synthetic workload consisting of two threads with each thread accessing an array that is not shared with the other thread. The time taken by each thread to access this array is measured.

Each thread does a series of read-only or write-only accesses to successive elements of the array using a cache line stride (64 bytes). The test iterates through all permutations of read-read, read-write, write-read, and write-write for the access patterns of the two threads. Each array is sized at 64MB— significantly larger than the cache size.

This synthetic test is neither a pure memory latency test nor a pure memory bandwidth test; rather it places varying throughput and capacity demands on the resources of the system described in the previous section. This provides an understanding of how the system behaves when any of the

Chapter 2

Experimental Setup

15

Page 14 Page 16
Page 15
Image 15
AMD 64 manual Synthetic Test, Internal Resources Associated with a Quartet Node
Page 14 Page 16

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