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A Guide To Server Processors

Fourth Edition

Published June 2015

Authors: Jag Bolaria, Tom R. Halfhill and David Kanter

Single License: $4,495 (single copy, one user)
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Analyzing the Processors for Scalable Computing

The server-processor market is changing, creating openings for new vendors. With the emergence of mega data centers and cloud computing, server economics no longer focus on capital expenses alone. In addition to high performance, server customers need to balance capital expenses and operating costs. Performance per watt and performance per watt per dollar are the new metrics driving purchasing decisions in large data centers. Physical density is also growing in importance, driving greater scalability and new form factors such as microservers that pack more nodes into precious rack space.

In this new era, backward compatibility is less important than before and innovation takes the front seat. Intel and AMD — the incumbent vendors — continue to innovate and advance their Xeon and Opteron designs, respectively. Integration, microarchitecture advances, and process technology are the primary factors in x86 evolution. But new entrants are eyeing cloud-computing environments as an opening for CPU architectures that are more power efficient.

Product Information Tempered With In-Depth Analysis

This report covers merchant-market processors designed specifically for servers. We provide detailed coverage of Intel’s Xeon D, E3, E5, and E7 product lines as well as its new Atom products for microservers. We cover AMD’s Opteron family, including Opteron X for microservers and the company’s new ARM processor. Other ARM-compatible products include AppliedMicro’s X-Gene 1 and X-Gene 2, Broadcom’s Vulcan, and Cavium’s ThunderX. This edition adds coverage for IBM’s Power8 processors and upcoming server processors from HiSilicon. We also speculate about future entries from Qualcomm and others. In addition, we continue our coverage of coprocessors (or accelerators) for high-performance computing (HPC), including Intel’s Xeon Phi, Nvidia’s Tesla, and AMD’s FirePro.

This report analyzes each vendor and each product, probing their strengths and weaknesses and presenting key details in a consistent, easy-to-compare fashion. We examine processor performance, integration, power dissipation, and overall system design. Where possible, we also evaluate the vendors' product roadmap.

Make Informed Decisions

As the leading vendor of technology analysis for microprocessors, The Linley Group has the expertise to deliver a comprehensive look at these technologies. Our analysts use their broad experience to deliver the technical and strategic information you need to make informed business decisions. And in case you are not familiar with all of the concepts involved in processor and server designs, the report includes several introductory chapters that define and describe terms such as superscalar, multithreading, pipelines, and virtualization.

This report is written for:

  • OEMs that need to make strategic vendor selections
  • ODMs supplying cloud-computing and HPC customers
  • Data-center architects looking at alternative platforms
  • Marketing and engineering staff at companies that sell other server components
  • Financial analysts who desire a detailed analysis and comparison of both incumbents and new vendors

What's New in This Edition

This fourth edition of “A Guide to Server Processors” has been extensively updated to include the latest vendor disclosures. Here are some of the many changes you will find:

  • Coverage of many new products from Intel, including Xeon D Xeon E5/E7v3 (Haswell), Xeon E5 4600, Xeon E3v3 (Haswell), and greater coverage of Xeon Phi (Knights Landing)
  • New coverage of AMD’s roadmap for x86 and ARMv8 processors
  • New coverage of Broadcom’s Vulcan CPU for future server processors
  • New coverage of IBM’s Power8 and the OpenPower Foundation
  • Updated coverage of AppliedMicro’s X-Gene 1 processor, the server industry’s first ARMv8 product, and new coverage of its successor, X-Gene 2
  • Updated coverage of Cavium’s ThunderX, a multicore ARMv8 design based on the company’s successful Octeon III architecture
  • Extensive updates to company information, roadmaps, and analysis
  • Forecast for ARM and x86 server processors through 2019
  • New coverage of HiSilicon’s server processor

Cloud computing and hyperscale data centers operated by companies like Amazon, Apple, Facebook, Google, and Microsoft are changing the market for server processors, creating opportunities for new vendors. In the past, raw processor performance and capital expenses were the vital metrics. Today, long-term operating costs are equally important. Performance per watt and performance per watt per dollar are the new metrics driving purchasing decisions in large data centers. Physical density is also growing in importance, driving greater scalability and new systems such as microservers that pack more nodes into precious rack space.

Although software compatibility remains important, data-center customers are more willing than before to adopt new platforms if the cost savings and performance are compelling. This opening has created an opportunity for ARM and its numerous licensees to challenge the incumbent x86 architecture. But this drama is unfolding slower than expected. As 2015 dawned, only one 64-bit ARM server processor — AppliedMicro’s X Gene — was actually shipping in systems. Although more are coming soon, Intel is responding vigorously with new versions of its Xeon and Atom-based server processors.

Meanwhile, a new challenger has emerged: IBM. In partnership with its rapidly growing OpenPower Foundation, the company is offering its Power server processor on the merchant market for the first time. Because the server-processor market exceeds $9 billion annually, these newcomers can build a profitable business by taking only a few percentage points of share from Intel.

Server processors are raising performance using more CPU cores and more threads, which are extremely useful for parallel processing — running multiple tasks simultaneously. Intel’s Xeon products now offer as many as 18 cores per chip. Cavium’s 48-core ThunderX CN88xx is the largest ARM-compatible processor announced to date. Intel’s Hyper-Threading technology enables a CPU core to execute two threads at once, and Broadcom is developing ARM-compatible server processors that can run four threads per core. Together with advances in parallel-programming tools, these highly threaded processors are valuable for big-data analytics, web servers, scientific computing, transactional databases, and many other applications.

For low-cost processors targeting microservers, system-on-a-chip (SoC) design is now common. By integrating several functions that previously required two or more separate chips, SoCs can cut costs, reduce power consumption, and save board space. Those functions typically include memory interfaces and I/O interfaces. More often, they also include hardware accelerators for specialized tasks. All ARM server processors announced to date use SoC designs. Intel’s new Xeon D combines the CPU and south-bridge chips in a single package, mimicking these SoC products.

In the past year, Intel has refreshed its entire Xeon line, moving to 22nm FinFET technology to reduce cost and power while improving transistor performance. By contrast, all non-Intel server processors are still manufactured in 28nm or older technologies and lack FinFETs. The sole exception is IBM’s Power8, which is manufactured in a 22nm silicon-on-insulator (SOI) process. IBM has always owned and operated its own fabs but recently transferred them to GlobalFoundries, leaving Intel as the only vendor still manufacturing its own server processors for the merchant market. Intel’s 14nm process is already in volume production, but the low-end Xeon D is the only server processor using that node.

The other x86 vendor, AMD, is more static. Struggling financially, the company has managed only minor updates to its Opteron x86 server processors in recent years, falling further behind Xeon in performance and performance per watt. As a result, Opteron’s market share has dropped to 3%. The company’s server hopes rest on a new CPU micro-architecture, code-named Zen, that should reduce the performance gap. New CEO Lisa Su recently prioritized Zen over a new ARM project (K12) in hopes of keeping Zen-based products on track for 2016 production. In the meantime, AMD’s first ARM-compatible server processor, the Opteron A1100 (Seattle), was originally scheduled to ship in 2014, but with little customer interest, production has been delayed until 2015.

In late 2014, AppliedMicro’s X-Gene became the first 64-bit ARM server processor to reach the market. It is a highly integrated eight-core SoC that inherits several features from the company’s high-performance embedded processors. X-Gene 2 moves to newer 28nm technology and is scheduled for production in 3Q15.

Cavium is the next ARM server-processor vendor to reach the market. Its ThunderX CN88xx chips have been sampling since 4Q14 and are sched-uled for production in 3Q15. They have up to 48 CPU cores, allowing them to match the per-socket performance of low-end Xeon E5 products. ThunderX is well suited to scale-out applications (such as web servers) that can exploit its high parallelism.

Other ARM-compatible processors are in the pipeline. Broadcom has been developing Vulcan, a high-end ARM-compatible CPU core, for embedded and server applications; we expect the first Vulcan-based products to enter production in 2016, although the pending Avago deal may disrupt these plans. HiSilicon, a subsidiary of Huawei, has demonstrated a 16-core ARM server processor that could reach production this year. Qualcomm has confirmed its plans to develop ARM-compatible server processors but disclosed no timeframe for its entry.

List of Figures
List of Tables
About the Authors
About the Publisher
Executive Summary
1 Processor Technology
Processor Basics
Central Processing Unit (CPU)
MMUs and TLBs
Bus Bandwidth
CPU Microarchitecture
Scalar and Superscalar
Instruction Reordering
Pipelining and Penalties
Branch Prediction
Server Processors and Technologies
What Is a Server Processor?
System Buses
Memory Subsystem
PCI Express
Server Benchmarks
SPEC Benchmarks
TPC Benchmarks
2 Instruction Sets
x86 Instruction Set
Initial Instruction Set
Modern Extensions
ARM Instruction Set
Initial Instruction Set
ARMv7 Architecture
ARMv8 Architecture
3 Server System Technology
Basic Server Architecture
Main Memory
System-Logic Chipset
Baseboard-Management Controller
Multisocket System Design
Storage Interfaces
High-Performance Computing
RDMA Over Ethernet
Storage Networking
Server Form Factors
Operating Systems
Windows Server
Linux Server
Hypervisor Software
4 Technology and Market Trends
Technology Trends
x86 Versus ARM
SoC Integration
The Main-Memory Bottleneck
System Fabric
Scale Up Versus Scale Out
Cloud-Computing Workloads
High-Performance Computing
Market Outlook
Cloud Computing
Open Compute
Market Forecast and Segmentation
Processor Revenue and ASP
Addressable Market for ARM
Market Share
5 Intel
Company Background
Product-Line Overview
Key Features and Performance
Atom-Based Processors
Haswell-Based Xeon Single-Socket Processors
Broadwell-Based Xeon Single-Socket Processors
Haswell-Based Xeon Multisocket Processors
Internal Architecture
Haswell and Broadwell
Atom Silvermont
System Design
Xeon E3v3
Atom C2000
Xeon D1500
Xeon E5v3
Xeon E7v3
Product Roadmap
Xeon E3
Atom and Xeon D
Xeon E5 and E7
FPGA-Integrated Products
Company Background
Key Features and Performance
Mainstream Server Processors
Microserver Processors
Internal Architecture
Bulldozer and Piledriver CPUs
Jaguar CPU
ARM Processor
System Design
Opteron System Design
A1100 System Design
Product Roadmap
7 AppliedMicro
Company Background
Key Features and Performance
Internal Architecture
System Design
Development Tools
Product Roadmap
8 Cavium
Company Background
Key Features and Performance
Internal Architecture
System Design
Development Tools
Product Roadmap
Company Background
Key Features and Performance
Internal Architecture
System Design
Development Tools
Product Roadmap
10 HPC Coprocessor Vendors
Intel Xeon Phi
Company Background
Key Features and Performance
Internal Architecture
Programming Model and Tools
Product Roadmap
Nvidia Tesla
Company Background
Key Features and Performance
Design Details
Product Roadmap
AMD FirePro
Company Background
Key Features and Performance
Design Details
Product Roadmap
11 Other Vendors
Company Background
Key Features
12 Processor Comparisons
Microserver Processors
Single-Socket Platforms
Two-Socket Platforms
Four-Socket Platforms
13 Conclusions
Market Outlook
Opportunities for ARM
Vendor Outlook
Other ARM Vendors
HPC Coprocessors
Closing Thoughts
Appendix: Further Reading
Figure 1-1. Basic CPU design.
Figure 1-2. Simple superscalar processor design.
Figure 1-3. CPU pipelining examples.
Figure 1-4. Block diagram of a typical server processor.
Figure 1-5. Interleaved tasks on a multithreaded CPU.
Figure 3-1. Typical single-processor server architecture.
Figure 3-2. Typical multisocket server architecture.
Figure 3-3. Rack-mount servers and a standard-size rack.
Figure 3-4. Lenovo’s BladeCenter H.
Figure 3-5. Typical blade-server architecture.
Figure 4-1. Dell and HP microservers.
Figure 4-2. Cisco M-Series modular servers.
Figure 4-3. Facebook’s Yosemite design.
Figure 4-4. Server-processor shipments by segment, 2013–2019.
Figure 4-5. Server-processor revenue by form factor, 2013–2019.
Figure 5-1. Intel server-processor roadmap.
Figure 5-2. Block diagram of Intel Haswell microarchitecture.
Figure 5-3. Block diagram of Intel Haswell server.
Figure 5-4. Block diagram of Intel Silvermont microarchitecture.
Figure 5-5. Server design based on Intel Xeon E3-1200v3.
Figure 5-6. Server design based on Intel Atom C2570.
Figure 5-7. Server design based on Intel Xeon D1500.
Figure 5-8. Dual-socket server design based on Intel Xeon E5-2600.
Figure 5-9. Four-socket server design based on Intel Xeon E7v3.
Figure 6-1. Block diagram of AMD Bulldozer/Piledriver CPU module.
Figure 6-2. Block diagram of AMD Bulldozer/Piledriver microarchitecture.
Figure 6-3. Block diagram of AMD Opteron X server chip.
Figure 6-4. Block diagram of AMD Opteron A1100 server chip.
Figure 6-5. AMD Opteron 4300 two-socket system design.
Figure 6-6. AMD Opteron 6300 four-socket system design.
Figure 7-1. Block diagram of AppliedMicro Potenza CPU core.
Figure 7-2. Block diagram of AppliedMicro X-Gene 2 processor.
Figure 7-3. Gigabyte Micro-ATX board with AppliedMicro X-Gene 1.
Figure 8-1. Block diagram of Cavium ThunderX CN88xx.
Figure 8-2. Dual-socket system design using Cavium ThunderX.
Figure 9-1. IBM Power8 memory architecture.
Figure 9-2. Block diagram of IBM Power8 CPU core.
Figure 9-3. IBM Power8 multiprocessor cluster.
Figure 10-1. Intel Xeon Phi coprocessor card.
Figure 10-2. Microarchitecture of Intel Xeon Phi core.
Figure 10-3. Conceptual block diagram of Xeon Phi coprocessor.
Figure 10-4. Block diagram of Tesla GK110 SMX array.
Figure 10-5. Block diagram of a GCN compute unit.
Table 1-1. Selected SPEC benchmarks.
Table 5-1. Summary of selected Intel x86 server processors.
Table 5-2. Key parameters for selected single-socket Intel server processors.
Table 5-3. Key parameters for selected dual-socket Intel Xeon processors.
Table 5-4. Key parameters for selected Intel multisocket Xeon processors.
Table 6-1. Key parameters for AMD Piledriver-based Opteron processors.
Table 6-2. Key parameters for selected AMD Opteron processors.
Table 6-3. Key parameters for AMD microserver processors.
Table 6-4. Key parameters for AMD SR56x0 north-bridge chips.
Table 6-5. Key parameters for AMD SP5100 south-bridge chip.
Table 7-1. Key parameters for AppliedMicro X-Gene processors.
Table 8-1. Key parameters for Cavium ThunderX server processors.
Table 9-1. Key parameters for IBM Power8 merchant processors.
Table 10-1. Key parameters for Intel Xeon Phi coprocessor cards.
Table 10-2. Key parameters for Nvidia Tesla coprocessor cards.
Table 10-3. Key parameters for AMD FirePro S-series coprocessor cards.
Table 11-1. Additional erver-processor vendors.
Table 12-1. Comparison of selected microserver processors.
Table 12-2. Comparison of high-performance single-socket processors.
Table 12-3. Comparison of processors for dual-socket servers.
Table 12-4. Comparison of processors for four-socket servers.


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