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Embedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University of Maryland at College Park USA
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Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

May 01, 2018

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Page 1: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Embedded Systems, Memory Systems, and Embedded Memory Systems

Prof. Bruce JacobElectrical & Computer EngineeringUniversity of Maryland at College ParkUSA

Page 2: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Yesterday’s high-performance technologies are today’s embedded technologies, but yesterday’s embedded-systems issues are today’s high-performance issues

Ankush Varma, U. Maryland PhD 2007 (Intel)

Page 3: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Four-Day Overview

1. Embedded Systems

2. Memory Systems

3. Memory Systems, cont’d (DRAM Systems detail if time)

4. Embedded Memory Systems

Page 4: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Part I. Embedded Systems

Page 5: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Today’s Story

• What are embedded systems? (more than just processor and/or software)

• What is the main problem?(difficult to verify that they work correctly)

• Why has it become a problem?(now in the era of non-classical systems)

• What is/are the solution/s?     :)

Page 6: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Perspective

• High-Performance Design Space (yesterday): Performance

• High-Performance Design Space (today): Performance and Power

• Embedded-System Design Space: Correctness of design,Predictability, Reliability, Power Dissipation, Size,Cost, …Performance

Page 7: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

EMBEDDED SYSTEMS

Page 8: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

CommunicationNetwork/s

(Multi-Mode)

Sensor/s(Multi-Mode)

Microprocessor/sand dedicated

softwarePower Supply(Self-Sufficient)

Actuator/s(Multi-Mode)

A DISSECTION

Page 9: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Actuator/s(Multi-Mode)

A DISSECTION

Power Supply(Self-Sufficient)

CommunicationNetwork/s

(Multi-Mode)

Sensor/s(Multi-Mode)

Microprocessor/sand dedicated

software

Page 10: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Characteristics

• Dedicated function (not general-purpose)

• Interact with environment (real-time)

• Resource-constrained (power, space, cost)

• Safety-critical (loss of life, property, etc.)

• Increasing pressure on time-to-market

THIS IS A BAD MIX

Page 11: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Examples Abound …

Official Trapped in Car After Computer Fails Mon May 12, 2003 09:44 AM ET

BANGKOK (Reuters) - Security guards smashed their way into an official limousine with sledgehammers on Monday to rescue Thailand's finance minister after his car's computer failed.

Suchart Jaovisidha and his driver were trapped inside the BMW for more than 10 minutes before guards broke a window. All doors and windows had locked automatically when the computer crashed, and the air-conditioning stopped, officials said.

'We could hardly breathe for over 10 minutes,' Suchart told reporters. 'It took my guard a long time to realize that we really wanted the window smashed so that we could crawl out. It was a harrowing experience.'

Page 12: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Examples Abound …

Microsoft Technology Hits the Road in BMW 7 Series

Microsoft Navigates the Automotive Industry, Enhances the Driver Experience

REDMOND, Wash. -- March 4, 2002

Page 13: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

THE PROBLEM

Page 14: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

COMPONENTS MAY BE VERIFIABLE, BUT THE SYSTEM IS NOT

Page 15: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

BehavioralDesign

StructuralDesign

PhysicalDesign

Fabrication,Deployment

Logic (RTL)Representation

SchematicDiagram

PhysicalLayout

Logic Libs & Synthesis Physical Libs, P & R Design Rule Checks

WorkingSilicon

VLSI Design Flow: characterized by strict design rules, verifiable physical design

A Tale of Two Design Flows

Page 16: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

BehavioralDesign

StructuralDesign

PhysicalDesign

Fabrication,Deployment

Logic (RTL)Representation

Logic Libs & Synthesis Physical Libs, P & R Design Rule Checks

module fibonacci(clk2, rst_l, out_w);

input clk2, rst_l;output [7:0] out_w;

reg [7:0] src1, out;wire [7:0] out_w = out;

always @(posedge clk2)begin if(!rst_l) begin src1 <= 1'd0; out <= 1'd1; end else begin src1 <= out_w; out <= src1 + out_w; endend

endmodule

A Tale of Two Design Flows

Page 17: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

BehavioralDesign

StructuralDesign

PhysicalDesign

Fabrication,Deployment

SchematicDiagram

Logic Libs & Synthesis Physical Libs, P & R Design Rule Checks

A Tale of Two Design Flows

Page 18: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

BehavioralDesign

StructuralDesign

PhysicalDesign

Fabrication,Deployment

PhysicalLayout

Logic Libs & Synthesis Physical Libs, P & R Design Rule Checks

A Tale of Two Design Flows

Page 19: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

BehavioralDesign

StructuralDesign

PhysicalDesign

Fabrication,Deployment

Logic Libs & Synthesis Physical Libs, P & R Design Rule Checks

WorkingSilicon

A Tale of Two Design Flows

Page 20: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

BehavioralDesign

StructuralDesign

PhysicalDesign

Fabrication,Deployment

Logic (RTL)Representation

SchematicDiagram

PhysicalLayout

Logic Libs & Synthesis Physical Libs, P & R Design Rule Checks

WorkingSilicon

VLSI Limitation: you can build WIRES or TRANSISTORS

VLSI Design Flow: characterized by strict design rules, verifiable physical design

A Tale of Two Design Flows

Page 21: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

EmbeddedApplication

Algorithm(Software)

ComponentDesign/Test

Integration,Deployment

FunctionalSpecification/s

HW/SW Co-Design Synthesis Models Open Problem

WorkingSystem

?

Architecture(Hardware)

ComponentDesign/Test

ComponentDesign/Test

Embedded Design Flow: characterized by nonexistent design rules, ad hoc methods for system-level verification

A Tale of Two Design Flows

Page 22: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Examples Abound …

“System Level EMC Testing of Spacecraft,” Narvaez, EMC 2003.Jet Propulsion Laboratory, California Institute of Technology

Page 23: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

NON-CLASSICAL SYSTEMS

Page 24: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Classical Systems

Analysis of this system requires guarantees of no out-of-band interactions

Page 25: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Classical Systems

Analysis of this system requires guarantees of no out-of-band interactions

Page 26: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Embedded System

Microcontroller/s, DSP/s, Bus/ses

...Task Task Task

Analog Component/s(sensors, etc.)

MEMS Component/s(actuators, etc.)

Network/s

Embedded RTOS

A Classical System?

Analysis of this system requires guarantees of no out-of-band interactions

NOISE

HE

AT

HEAT

HEAT

Page 27: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Embedded System

Microcontroller/s, DSP/s, Bus/ses

...Task Task Task

Analog Component/s(sensors, etc.)

MEMS Component/s(actuators, etc.)

Network/s

Embedded RTOS

A Classical System?

Analysis of this system requires guarantees of no out-of-band interactions

TIMING

UNPREDICTABILITY

UNPREDICTABILITY

Page 28: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

THE SOLUTIONI

Page 29: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

EXTREMELY ACCURATE MODELS

Page 30: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

• Extremely accurate software model of embedded hardware

• Runs unmodified RTOS and application binaries

• Models performance and energy consumption

• Allows arbitrary probing & debugging of system

Existing: SimBed

Task

Real-Time OS

SimBed(Emulated Hardware)

Workstation

Task Task

Page 31: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

… Expanded

Task

Real-Time OS

SimBed(Emulated Processors, Devices, Networks,

etc.)

Workstation

Task TaskAc

tuat

ors

Sens

ors

MEM

S

Page 32: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

But Wait, There’s More

OUT-OF-BAND EFFECTS:

• Electromagnetic Interference

• Thermal Interference

• Mechanical Interference

• etc. …

Page 33: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

But Wait, There’s More

OUT-OF-BAND EFFECTS:

• Electromagnetic Interference

• Thermal Interference

• Mechanical Interference

• etc. …

300MHz

500MHz

1GHz

RF_clk_1GHz

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

0 100 200 300 400 500 600

Time [us]

Volta

ge[V

]

-8

-6

-4

-2

0

2

4

6

8

Counter Output RF pulse envelope

RF_clk_500M

-2

-1

0

1

2

3

4

5

0 100 200 300 400 500 600

Time [us]Vo

ltage

[V]

-8

-6

-4

-2

0

2

4

6

8

Counter Output RF pulse envelope

RF_clk_300M

-1.5

-1

-0.5

0

0.5

1

1.5

2

2.5

3

3.5

0 100 200 300 400 500 600

Time [us]

Volta

ge[V

]

-8

-6

-4

-2

0

2

4

6

8

Counter Output RF pulse envelope

Page 34: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

But Wait, There’s More

OUT-OF-BAND EFFECTS:

• Electromagnetic Interference

• Thermal Interference

• Mechanical Interference

• etc. …

Page 35: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

But Wait, There’s More

OUT-OF-BAND EFFECTS:

• Electromagnetic Interference

• Thermal Interference

• Mechanical Interference

• etc. …

Image: Morgan, Waits, Kastantin and Ghodssi, University of Maryland, Feb. 2003

Page 36: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

But Wait, There’s More

OUT-OF-BAND EFFECTS:

• Electromagnetic Interference

• Thermal Interference

• Mechanical Interference

• etc. …

I3 I4I2

I6

I1

I5

I7

GATE

SOURCE DRAIN

BODY

Device Physics?

Page 37: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

What is Required?

• Expertise in design: VLSI, PCB, system

• Expertise in tools: CAD, codesign, compiler

• Expertise in digital, mixed-mode, MEMS, …

• Expertise in controls, networks

• Expertise in real-time systems software

• Proven ability to make things that work

Page 38: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

What is Required?

• (most importantly) Foresee all possibilities

Page 39: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

THE SOLUTIONII

Page 40: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Come up with a totally new understanding

Page 41: Embedded Systems, Memory Systems, and …blj/talks/1.pdfEmbedded Systems, Memory Systems, and Embedded Memory Systems Prof. Bruce Jacob Electrical & Computer Engineering University

Perspective, Revisited

• Embedded systems care about correctness of design

• Embedded systems are becoming increasingly complex,involving many heterogeneous components

• The embedded-systems community has SOLVED (or at least ADDRESSED more-or-less successfully) issues of correctness, power/space, etc. … in particular the very issues that now confront the general-purpose community(granted, issues have been addressed rel. to older technology, but still …)

• (next time) The memory system has become the dominant concern in performance, and it is rapidly becoming a/the dominant concern in power.

• Time to take a page from the embedded-systems community …