Slide 1

Windows PC Accelerators

Reporter：吳柏良

Slide 2

Outline

Introduction Windows SuperFetch Windows ReadyBoost Windows ReadyDrive Conclusion

Slide 3

Introduction

Windows PC Accelerators are the mechanism used in Windows Vista to improve performance especially on I/O response time.

Ensuring Memory is well Utilized SuperFetch ： an memory manager that analyzes usage p

attern over time to optimize memory content Avoiding the Disk Bottleneck

ReadyBoost Expanded Memory Devices ： support the use of flash storage devices to boost PC performance

ReadyDrive Hybrid Hard Drive ： support the use of hybrid hard drives (H-HDDs)

Slide 4

Poor Memory Contents

Typical Memory Pressure Scenario1. Memory is populated with pages for Application A

2. Application B is loaded, pushing App A’s pages out

3. User switches back to Application A

4. Application A reloads pages as needed through Pagefaults, pushing out Application B’s pages

5. Repeat cycle…

Slide 5

Disk Seek Time Problem

Drive Industry Continues to Deliver Impressive Data Rate, Rotation and Interface Speed Improvements

ATA/33 ATA/66 ATA/100 SATA 4200RPM 5400RPM 7200RPM 10000RPM 2 MB 8 MB 16 MB Result ： Sequential IO rates of 80 MB/s+

At that rate, 1 GB of RAM fully populated in ~12.8sec Seek Times Improving, but not as Significantly

3.5” Desktop drive avg seek ~10 mSec 2.5” Mobile drives ~12.5 mSec Much better when hitting the track buffer… Result ： Random IO rate limited to an effective 1MB/sec

At that rate, populating 1GB of RAM takes ~1024sec!

Slide 6

Disk Seek Time Problem

50% of MobileMark 2005 I/Os are 4 KB and Random

Files and Structured Files A single DLL is generally 5 to 6 Disk Locations (min)

Directory, MFT Entry, and other File System Metadata Programs like Internet Explorer, Adobe Reader, or

Outlook use over 100 DLLs Logging, Transactions, Application Temp Files

A simple Registry Write can require 5 to 6 Random and

Ordered Disk Writes

Slide 7

Outline

Introduction Windows SuperFetch Windows ReadyBoost Windows ReadyDrive Conclusion

Slide 8

Windows SuperFetch

SuperFetch analyzes memory usage patterns to determine the optimal memory content.

SuperFetch uses a lightweight, sophisticated tracking algorithm to determine which pages a user uses most frequently.

When the PC has free physical memory, SuperFetch places candidate pages into memory to make the PC more responsive.

SuperFetch manages both RAM and cache memory.

Slide 9

Outline

Introduction Windows SuperFetch Windows ReadyBoost Windows ReadyDrive Conclusion

Slide 10

Windows ReadyBoost

ReadyBoost supports the use of nonvolatile flash storage devices to boost system performance.

Allows fast reads to satisfy page faults when page is not in main memory and significantly outperforms disk in random reads by avoiding the rotational and seek latencies.

Slide 11

Windows ReadyBoost

Write-through cache allows user to remove device at any time

Secure Data is encrypted using AES 128bit crypto

Efficient Data is compressed by a factor of 1.8X to 2.3X

Slide 12

Windows ReadyBoost

Using a simulated workload on a PC running Windows Vista

ReadyBoost Capacity

Time to complete workload (s)

Percent Improvement

0 MB 42.25 --

512 MB 27.12 36.12

1024 MB 25.21 40.61

2048 MB 24.72 41.78

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Implement Consideratins

Flash Performance 5 MB/s for random 4K reads 3 MB/s for random 512K writes

Flash Capacity 3:1 ratio of ReadyBoost cache size to main memory size w

ill realize optimal performance. Flash Wear

Unique write gathering algorithm optimizes performance and wear patterns

Projected life of devices 19.4 – 1823 years depending on device size, variant, and usage patterns

Slide 14

Outline

Introduction Windows SuperFetch Windows ReadyBoost Windows ReadyDrive Conclusion

Slide 15

Windows ReadyDrive

Up to 90% Power Saving when

powered down

Read and Write instantly while

spindle stopped

Read instantly even while spindle spinning for higher

IO rate

ATA ATA InterfaceInterface

Disk comes ready in less than 1

second

NVCache

DRAMCache

Slide 16

Hybrid Hard Disk Boot And Resume

During shutdown or hibernate all the disk sectors needed to boot or resume are pinned into the NV cache

On next power on the BIOS POST runs and the disk is powered on but the spindle won’t be ready for 2-4 seconds

BIOS can read data from the NV cache and all boot process IO can be read from the NV Cache

Once the rotating media is ready IO can be satisfied by both NV Cache and rotating media for optimized read performance

2.5” HDD2.5” HDD

Hard DiskController

NV Cache

MotherboardMotherboard

DRAM

ATAController

Windows Vista OS

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ReadyDrive System Startup

Hybrid HDD comes ready faster and fast BIOS POST reads from disk earlier

LBAs needed to start boot process are read fromNV Cache before the magnetic spindle is ready

No seek times for data in NV Cache for the remainder of startup

BIOS andDisk spin-up Read disk

Read NV Cache

Std HDD

Hybrid HDD Read disk and NV Cache

timetime

Slide 18

Power Saving Mode

SuperFetch buffers disk data in system DRAM to fulfill reads

Write IOs buffered in NV cache while disk is spun down

Disk spins up only when Read cache miss NV cache full

The disk spins-down and continues to use the NV cache

2.5” HDD

Hard DiskController

NV Cache

Motherboard

DRAM

ATA Controller

Windows Vista OS

Slide 19

Windows ReadyDrive

ReadyDrive is a hard disk drive with integrated nonvolatile flash memory that acts as a high-performance cache for writes and low-latency reads.

Performance Faster boot and Resume from Hibernate Faster and more consistent application launch Reduced disk contention

Saves battery power Increased system ruggedness and reliability

Slide 20

Windows ReadyDrive

Slide 21

Windows ReadyDrive Performance

Slide 22

Windows ReadyDrive Power Consumption

Slide 23

Implementatin Consideratins

ATA Command Set Control what data is pinned for retention in the NV cache Control the drive power mode

NV Cache Size The NV cache size as large as 256 MB to 1 GB would be

more effective. NV Cache Performance

> 4 MB/s 4 KB random reads to a file pinned in the NV Cache

> 4 MB/s 4 KB random writes to a file pinned in the NV Cache

> 8 MB/s 64 KB sequential writes to a file pinned in the NV Cache

> 16 MB/s 64 KB sequential reads to a file pinned in the NV Cache

Slide 24

Conclusion

Microsoft introduces three mechanisms to improve system performance.

SuperFetch： an memory manager that analyzes usage pattern over time to optimize memory content

ReadyDrive： support the use of flash storage devices to boost PC performance

ReadyBoost： support the use of hybrid hard drives (H-HDDs)

Slide 25

Reference

http://www.microsoft.com/whdc/system/sysperf/perfaccel.mspx

http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/STO008_WH06.ppt

http://download.microsoft.com/download/5/b/9/5b97017b-e28a-4bae-ba48-174cf47d23cd/CPA131_WH06.ppt

Slide 26

Thank You!