Accelerating SSD Performance with HLNAND

Santa Clara, CA USAAugust 2008 1

Accelerating SSD Performance with HLNAND

Roland Schuetz

MOSAID Technologies Inc.

David Won, INDILINX


Presentation Outline

PC Architecture and the Solid State Drive HLNAND Introduction HLNAND Enhances SSD Performance Conclusions


PC System ArchitectureWhere are the Bottlenecks?

CPU

North Bridge

South Bridge

GPU DRAM

HDD

BIOS

DRAM/GDRAM

PC System ArchitectureMigration of System Memory

Creating New MemorySub-Architecture

Utilize Upgraded PCIelink for New Storage

Memory Sub-Architecture

Most Memory Interfaces and System Interconnect Have

Undergone Dramatic BW Upgrades Over the Years

Bulk Storage Access BW Lags(Mechanical Latency)

DRAM


Three categories:• Enterprise• Notebook / PC• NetBook / Ultraportable

Three cost models:• >$100 non-NAND in

Enterprise SSD’s• ~$5.00 non-NAND BOM in

Notebook SSD’s• <$1.00 non-NAND BOM in

NetBook / Ultraportable SSD’s

Enterprise

Notebook

NetBook / Ultraportable

SSD Market Segment

Source: STECSource: SanDisk

Source: STEC


Enterprise application move huge amounts of data and are IO bound

These include:• File, web, transaction servers• Multimedia editing systems• Simulation

servers/workstations

Current Flash based enterprise applications based on conventional, 40 – 100 MBps sub-systems

Source: Violin 1010 Memory Appliance, Violin Memory, Inc.

Enterprise Flash Storage Excellent Market for HLNAND SSDs


Current SSD Offerings (1st Generation)

Leading NAND, memory module, and specialized SSD manufacturers offer conventional NAND flash based product

Cost is pivotal for SSD adoption Little product and architectural differentiation

• 4 channel• 4-way interleave

Similar cost structure• NAND flash constitutes the majority of the BOM• Vertically integrated manufacturers have pricing advantage

Similar performance• 30 ~ 100MB/s Read/Write performance• No one competitor has performance lock on the market


How are Current SSDs Stacking Up?

Source: Engadget


Current SSDs vs. HDDs

59.9 MB/s

76.5 MB/s

85.9 MB/s

50.1MB/s

60.0 MB/s

94.6 MB/sMTRON SSD 2.5"SATA150, 32GB

86.9 MB/sWestern Digital HDD, WD1500ADFD

150GB, SATA150, 10,000 rpm(Enterprise HDD)

68.3MB/sSanDisk SSD5000SATA150, 32GB

Fujitsu HDD, MHW2160BJ160GB, SATA300, 7200 rpm

MTRON SSD 2.5"SATA150, 32GB

Western Digital HDD, WD1500ADFD150GB, SATA150, 10,000 rpm

(Enterprise HDD)

SanDisk SSD5000SATA150, 32GB


Window XP Startup PerformancePCMark05 HDD Benchmark

25.9

51.5

10.9

7.9

(MB/s)

Read Throughput Write Throughput

Sources: Tom’s Hardware, Mtron SSD 32 GB: Performance with a Catch,Patrick Schmid, Achim Roos, November 21, 2007;Tom’s Hardware, Flash-Based Hard Drives Cometh,Patrick Schmid, Achim Roos, August 13, 2007;


HLNAND – New High Speed NAND Standard

HLNAND Unidirectional, point-to-point, daisy-chain

cascade with programmable link width; 1- 8 bits

Synchronous DDR signaling up to 800Mb/s/pin

Each ring supports up to 255 devices with no bandwidth degradation

Single CE per ring enables pin controller count reduction

Low Power 1.8V I/O

Controller

HLNAND

HLNAND

HLNAND

HLNAND

Controller

HLNANDHost

Interface

HLNAND

HLNAND

HLNANDNAND NAND NAND

CE1CE2

CE3Host

Controller

Conventional NAND 8 bit, bidirectional, multi-drop bus

Asynchronous LVTTL signaling up to 40Mb/s/pin

Speed degradation with more than 4 devices on bus

Chip Enable (CE) signal required for each device

Power hungry 3.3V I/O


HLNAND – New High Speed NAND Standard (cont’d)

HLNAND New device features enhance

performance and simplify controller and SSD design

New, low-stress program scheme enables:

Random page program Page-pair erase Multi-page & Multi-block erase

Controller

HLNAND

HLNAND

HLNAND

HLNAND

Controller

HLNANDHost

Interface

HLNAND

HLNAND

HLNANDNAND NAND NAND

CE1CE2

CE3Host

Controller

Conventional NAND No new features to enhance flash

performance or simplify controller and SSD design


PC Demands on System Storage

Typical PC use is IO intensive -> frequent HDD/SSD access; Ex: creating slide presentation, virus scan, etc.

Booting PC is very IO intensive since the OS must load a large amount of data from bulk storage to DRAM


IO Operation ExampleCan SSD Deliver “Instant Boot”

Populate 1GB DRAM from Flash Based Bulk Storage

Conventional Flash SSD with 60MB/s BW takes ~17sec

Optimized conventional flash SSD with 95MB/s* takes ~10 sec

* Mtron SSD 32 GB: Performance with a Catch Patrick Schmid, Achim Roos, November 21, 2007; SSD: Mtron MSDSATA6025032NA

10 Seconds is very observable time!


IO Operation ExampleCan SSD Deliver “Instant Boot”

Populate 1GB DRAM from Flash Based Bulk Storage

HLNAND HL1 SSD with 266MB/s BW takes ~3.8sec

HLNAND HL2 SSD with 800MB/s BW takes ~1.3sec

HLNAND based SSDs offer 260% - 450% and up to 800% IO rate improvement. 3.8 sec. not instant, but much closer


IOPS are Holly Grail in Enterprise Applications

SSDs offer significantly higher I/O (inputs/outputs) per second Than HDDs: HLNAND will shine

HDD (typical enterprise class) ~150 SSD, SATA (advertised by Sandisk)

7,000 SSD, 4G Fiber Channel (advertised by

STEC) 45,000 HLNAND 300,000*Source: Sandisk, STEC, and Deutsche Bank estimates

I

O P S

* Assume similar design to STEC SSD and multiply by media speed improvement; 45,000 * (266/40).Not including 4GFC saturation limit.Holy Grail of the Monastery of Xenophontos, Macedonian Heritage, 2000-2008


SSD Controllerfor HLNAND

HL1 RingHost Interface

Max. Media BW = 1066MB/s @x8b, 4 rings Total 96 signal pins excluding power: 24 signal pins per ring

SSD Controllerfor NAND

Channel 1 - Max. 25MB/s x8b



Parallel Bus

Host Interface

Max. Media BW = 200MB/s @x8b, 8 channels Total 208 signal pins excluding power: 29 signal pins per

channel, 8 CE# and 8 R/B# per channel

32 dies per ring

16 dies per channel, no termination

128GB SSD using 128 * 8Gb SLC

Ring 1 - Max. 266MB/s @x8b

SSD Performance ComparisonHLNAND-based vs. NAND-based

Ring 1 - Max. 266MB/s @x8b


HLNAND SSD vs. NAND SSD

266 MB/s per ring 1 ring to saturate SATA1

(1.5Gbs, 188MB/s) 2 rings to saturate SATA2

(3Gbps, 375M/s) Reduced pin count; 24

ctrl/data pins per ring Expanded feature set reduces

controller overhead Pwr/Media BW : 1.87mW/MB/s

Max. 40MB/s per channel 4-5 channels to saturate

SATA1 8-10 channels to saturate

SATA2 Ctrl/data pin count 29 per

channel No new overhead-reducing

features Pwr/Media BW: 8.96mW/MBs

8 Bit HLNAND-based SSD 8 Bit NAND-based SSD


HLNAND SSD vs. NAND SSDRead Throughput, Experimental Results

HLNAND-based SSD, Media Rate NAND-based SSD, Media Rate

Plots from Mobile Embedded Lab, University of Seoul, 2008


HLNAND SSD vs. SSD vs. HDDEstimates and Measured Performance

Read Throughput

60.0 MB/s

210 MB/s

420 MB/s (SATA300 IO saturated @ 300 MB/s)

HLNAND SSD, HL1-266, 2KB page, 8bit Link, 1 Ring, SATA300

HLNAND SSD, HL-1266, 2KB page, 8bit Link, 2 Rings, SATA300

94.6 MB/s MTRON SSD 2.5"SATA150, 32GB

86.9 MB/sWestern Digital HDD, WD1500ADFD

150GB, SATA150, 10,000 rpm(Enterprise HDD)

68.3MB/s SanDisk SSD5000SATA150, 32GB Sources:

Tom’s Hardware, Mtron SSD 32 GB: Performance with a Catch,Patrick Schmid, Achim Roos, November 21, 2007;Tom’s Hardware, Flash-Based Hard Drives Cometh,Patrick Schmid, Achim Roos, August 13, 2007;Mosaid EstimatesFujitsu HDD, MHW2160BJ

160GB, SATA300, 7200 rpm

Throughput Calculation: Read throughput = (Maximum media BW) – (20% controller overhead)


HLNAND SSD vs. NAND SSDWrite Throughput, Experimental Results

HLNAND-based SSD, Media Rate NAND-based SSD, Media Rate

Plots from Mobile Embedded Lab, University of Seoul, 2008


HLNAND SSD vs. SSD vs. HDDEstimates and Measured Performance

59.9 MB/s

170 MB/s

339 (SATA300 IO saturated @ 300 MB/s)


HLNAND SSD, HL1-266, 2KB page, 8bit Link, 1 Ring, SATA300

HLNAND SSD, HL-1266, 2KB page, 8bit Link, 2 Rings, SATA300

76.5 MB/sMTRON SSD 2.5"SATA150, 32GB

85.9 MB/s Western Digital HDD, WD1500ADFD150GB, SATA150, 10,000 rpm

50.1MB/s SanDisk SSD5000SATA150, 32GB

Calculated base on MTRON SSD 2.5; (Read Throughput)/(Write Throughput) = 1.24HLNAND:(Read throughput) / 1.24 = (210MB/s)/1.24 ≈ 170MB/s

Sources: Tom’s Hardware, Mtron SSD 32 GB: Performance with a Catch,Patrick Schmid, Achim Roos, November 21, 2007;Tom’s Hardware, Flash-Based Hard Drives Cometh,Patrick Schmid, Achim Roos, August 13, 2007;Mosaid Estimates

Write Throughput


SSD Controller Design:Flash Translation Layer, FTL

FTL responsible for high cost jobs of wear-leveling and garbage collection

Wear leveling operations include• Merge• Switch• Switch after copy• Copy after PPE (Page-Pair Erase)• Migration


HLAND Improves FTL Performance

New HLNAND features reduce block recycling costs• Page-Pair Erase• Random page program• Partial block erase• Multi block erase


Wear Leveling Enhancement:Copy-After-Page-Pair-Erase

p

cpEE

N

CkCMC

Blk 0

1

2

3

4

Log 0

1

2

4

4

1. Page-pair erase

2. Copy

Copy-after-PPE

CE: Erase cost

Ccp : Copy cost

M : Number of blocks erased concurrently

Np: Number of pages in a block

k: Number of page-copies: Additional copy overhead

Page-pair erase introduces low cost wear-leveling opportunities

Translates into more greater system longevity and less controller overhead


Synthetic Workload Experiment X8b 4KB page size 256KB block size 2048 blocks/bank 1 bank

Experiment performed by Mobile Embedded Lab, University of Seoul, 2008

Read Program Copyback Erase

60% 25% 10% 5%

617 263 82 38

Wokload

0

5000

10000

15000

20000

25000

30000

35000

40000

1 2 3 4 5 6 7 8 9 10

# of Chip per Ring/Bus

To

tal E

lasp

ed T

ime

(us)


Register

Cache

DRAM (5.3 ~ 6.4GB/s per Channel)

HDD (20 ~ 70MB/s)

Memory BWGap

Historical Storage Hierarchy

Register

Cache

DRAM (5.3 ~ 6.4GB/s per Channel)

HDD (20 ~ 70MB/s)

HLNAND(500MB/s ~ 1GB/s)

New Storage Hierarchy

New Hierarchy for New User Experience


Conclusions

High Speed Interface

Low Power Consumption

High Scalability

Interface Extensibility

Reduced Overall Cost with Increased Performance

Advance Core Features

HLNAND’s features contribute to the acceleration of SSD satisfaction and adoption

Accelerating SSD Performance with HLNAND

Documents

hlnand ssd

gb ssd

stec ssd

mtron ssd

ring ssd controller

nandbased ssd controller

ssd performance conclusions

sec hlnand hl2 ssd