[cst031] graphics and console hardware and real-time …hardware. in this lecture we look at the...

[CSt031] Graphics and Console Hardwareand Real-time Rendering

5th Lecture :: The XBOX 360 ArchitectureDr. Michael Manzke

[email protected]

Trinity College Dublin

Dr. Michael Manzke :: CS7031 :: 5th Lecture :: The XBOX 360 Architecture :: October 20, 2010 – p. 1/22

A First Look at the XBOX 360Architecture

So far we covered general CPU and simple cacheorganisations.

We have not yet considered advanced optimisation.

This part of the course is about graphics and consolehardware.

In this lecture we look at the first console hardware.

This will help us to identify aspects or computerarchitecture that we need to investigate further.

You will use the Xbox 360 intensively for your shaderprograming in the second part.

A good appreciation of the underlying architectureshould help you with this.


The XBOX System Architecture Paper

The following slides are based on Andrews’ andBacker’s "XBOX 360 System Architecture"paper [AB06]. Figures on these slides are take fromthe paper.

A link to the paper, that can only be accessed bystudents in college, will be made available on thecourse’s web page.

[AB06] Jeff Andrews and Nick Baker. Xbox 360system architecture. IEEE Micro, 26(2):25–37, 2006.


System Overview

The live cycle of game consoles is approximately 5years.

Consequently we see greater advances than we wouldexpect in desktop or server architectures.

The figure on the next slide shows a top-level systemdiagram (Figure on Slide 10).

We can clearly idenfy the main components in thistop-level system diagram:

CPUGraphics Processing Unit (GPU)MemoryI/O


Top-level System Diagram


Design Objectives

The architecture should provide a balanced hardware for the software pipe.

Rendering

Animation

Physics

AI

Console design must meet the the power requirements.

The design choices include:

Number of CPU cores.

Number of GPU shaders

CPU L2 size

Bus bandwidths

Memory size


Design Features

The CPU has three cores that share:

A 8-way set-associative L2 cache.

The L2 cache has 1MB and is clocked at 3.2 GHz

Each of the three cores hold four-way single-instruction, multiple data (SIMD)vector units.

These components are optimised for graphics and game workloads.

The front-side bus (FSB) operates at 10.8 GB/s for reads and writes.

With 16 logical pins in each direction.

The FSB and L2 design allows the GPU to directly access the L2 cache.

The system’s I/O chip provides:

Xbox media audio XMA decoder.

on-the-fly decoding of compressed audio streams.

NAND flash controller

System management controller (SMC)


The Graphics Processing Unit andMain Memory

The GPU has:

48 parallel, unified shaders.10 MB embedded DRAM EDRAM

Operats at 256 GB/sFor hight bandwidth to frame buffer and z-buffer.

The Main Memory has:

512 MB unified memoryIs a 700-MHz graphics douple-data-rate-3 (GDDR3)memory.22.4 GB/s memory bandwidth


The CPU Component

PowerPC instruction set architecture

VMX SIMD vector instruction set (VMX128)

Customized for graphics workloads.

Shared L2 cache

Fine-graind, dynamic allocation of cache lines between the six threads

CPU core has two-per-cycle, in-order instruction issuance.

Two hardware threads per core.


CPU Chip Diagram


CPU Cached Data Streaming

The figure on the next slide is from the XBOX 360 SystemArchitecture Paper (Figure on Slide 12).


CPU Cached Data Streaming Diagram


A :: X360BlockDiagram04 (IBM)



The CPU Die Photo (IBM)


The GPU Design



GPU Block Diagram (ATI)


The GPU Die



The GPU Die Photo


The ERAM Die



The ERAM Die Photo


XNA Studio Integrated DevelopmentEnvironment (IDE)



XNA Studio (IDE) Screen Shot


[cst031] graphics and console hardware and real-time …hardware. in this lecture we look at the...

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