1

LOAD BALANCING SWITCH

By: Maxim Fudim Oleg Schtofenmaher Supervisor: Walter Isaschar

PROJECT POSTER

Winter - Spring 2008

2

Abstract

Software solutions for real-time are too slow

Power dissipation limits work frequencies

Greater computing power neededH/W accelerators may improve S/W

processesMulti-core, multi-threaded systems

are the future

3

Multiprocessor environment for parallel processing of vectors data stream

Maximal ThroughputConfigurable hardwareExpandable designStatistics report

Project Goals

4

System specifications

SW over transparent HWInterface over PCI 1 Mbit/sec input streamVectors of 8 ÷ 1024 chunksVariable number of processorsSystem spreads over multiple FPGAs

5

Problem How to manage Data stream? How to manage multiple parallel units? How to achieve full and effective

utilization of resources?

6

Solution (Top Level)Board Level Load Balancing SwitchOne system input and output to

PCIDistribute vectors among classes Local buffers for chip data

7

Solution (Chip Level)

Chip Level Load Balancing SwitchConverting shared resources to

“personal” work space.Cluster ‘s organized VPUsMonitoring for each unit’s loadSmart arbitrationFlexible and easy configuration

8

Solution - Tree Distribution Switch

Class of Service Distribution

SW/HW interface

Clusters of VPUs

Clusters of VPUsClusters

of VPUs

LBS Arbitration

Clusters of VPUs

Clusters of VPUsClusters

of VPUs

LBS ArbitrationCluster

s of

VPUs

Clusters

of VPUs

Clusters

of VPUs

LBS Arbitration

9

Three level Architecture

Provide level for packets management ( Classes )Type, Size, Priority of Data

Provide level for organizing various processing units ( Clusters )Speed , Quantity, Resources of

Processors

Provide level for fine tuning ( VPUs ) Algorithm, HW accelerating

10

Implementation

Multi chip system connected over two busses

Input and Controls over Main BusOutput via streamed neighbored

bussesLocal FIFOs for every chip/classClassifier for packet managementSW configurable controlsCluster organized VPUs with in/out

arbitrationWatchdogs & Statistics Gathering

11S/W emulator or H/W DSP system

Board Level diagram

Input vectorsOutput reports

LBS1

Classifier

Stratix II 180

PROCStar IIPCI Bus

DDR2 DDR2

LBS2

DDR2 DDR2 DDR2 DDR2 DDR2 DDR2

LBS3 LBS4

Main Bus : Data In and Controls

Stratix II 180 Stratix II 180 Stratix II 180

Ring Bus

Ring Bus

Per LBS registers

12

Single FPGA Top Diagram

Load Balancing

Switch

(LBS)

DDR2Controls Bank A

LBS 1-4

Stratix II 180 FPGA

DDR2 Controls

Bank B

I/O – LBSControl Block

Data flow

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

NIOScluster

BusControl Block

13

Data Packet Format

Header Data 1 to N of 32-bit

WordsTail

……

Unused

Nios Numb

er Data

Length NVector ID/Command

Type

8-bit 32-bit16-bitVersion 4-bit

SW/HW Control 1-bit

Type 1-bit(Data/

Command)

Tail : Sync Data

Header:

14

LBS Class Top Level View

Main Controller

unit

Stratix II FPGA

Output Writer

Cluster ArbiterNIOS II Syste

m

Input Reader

Cluster ArbiterNIOS II Syste

m

Control

Control

FIFO Input Port

FIFOOutput

Port

Control

Cluster ArbiterNIOS II Syste

mMuxed output data bus

Input data bus

Controland Status

Statistics

Reporter

Buss

es C

ontr

ol B

lock

Organization of VPU’s(Vector Processing Units)NIOS VPUs joined into the clustersConstant number of ClustersParametric number of NIOS VPU’s

in clusterParametric control & distribution

logicVarious configurations of NIOS Static/Dynamic Priority Arbitration

16

Single processor with in/out buffers

HW accelerated systemShared resources system with

mutexMulti- processors system with

number of ports to Cluster

LBS Units DescriptionVPUs: NIOS System

17

Resource Usage

ModuleLogic

utilization

%Memor

y (M4K)

%

Peripheral IPs (MegaFIFO, PLLs, etc.) 3,100 2 16 2

User System (All VPUs + LBS) 42,000 30 675 88

Single VPU 6,775 4.7 112 15LBS Logic 1,350 1 3 0.5Total usage of chip resources 45,896 32 691 90

Total available 143,000 100 768 100

Resource usage data for 6 VPU system

VPU resource usage is based on basic VPUs and may be decreased by advanced configurations and policies.

18

Performance of LBSTheoretical Throughput:

100MHz x 64bit = 6.4Gbit/sArbitration and routing latency:

2-4 cycles in average60% effective bandwidth utilization

for short vectors, up to 98% for long vectors

1Mbit/s – 400 Mbit/s real throughput PCI and slow algorithms =

bottlenecks

19

Performance for short vectors

SystemTime ofService[sec]

Throughput[Mbit/s] Impr

SW(on Core2Duo

E6600)0.1 3.2

6 VPUs 0.00209 122 382 Classes of 6 VPUs 0.00134 191 603 Classes of 6 VPUs 0.00086 297 93

4 Classes of 6 VPUs 0.00064 400 125

Time and throughput for 1000 vectors of 4 chunks each

VPU performance is based on basic VPUs and RR arbitration and may be increased for giving workload after perf. analysis by defining advanced configurations and policies.

20

Performance for medium vectors

SystemTime ofService[sec]

Throughput[Mbit/s] Impr

SW(on Core2Duo

E6600)2.9 2.3

6 VPUs 0.28 23.4 102 Classes of 6 VPUs 0.15 43.5 18.53 Classes of 6 VPUs 0.01 66 28.7

4 Classes of 6 VPUs 0.074 88 38

Time and throughput for 1000 vectors of 200 chunks each

VPU performance is based on basic VPUs and RR arbitration and may be increased for giving workload after perf. analysis by defining advanced configurations and policies.

21

Performance for long vectors

SystemTime ofService[sec]

Throughput[Mbit/s] Impr

SW(on Core2Duo

E6600)1.1 2.9

One VPU 1.224 2.62 0.896 VPUs 0.208 15.43 5.3

2 Classes of 6 VPUs 0.11 29.1 103 Classes of 6 VPUs 0.074 43.69 14.8

4 Classes of 6 VPUs 0.061 52.46 18

Time and throughput for 100 vectors of 1000 chunks each

VPU performance is based on basic VPUs and RR arbitration and may be increased for giving workload after perf. analysis by defining advanced configurations and policies.

22

System performance – missing TOAs

0 2 4 6 8 10 12 14 16 18 200.000

0.100

0.200

0.300

0.400

0.500

Missing TOAs

HardwareSoftware

Number of missing TOAs

Proc

essi

ng t

ime

[sec

]

23

System performance – noise levels

0 5 10 15 20 25 30 35 40 45 500.000

0.100

0.200

0.300

0.400

0.500

0.600

Noise percentage

HardwareSoftware

Noise [%]

Proc

essi

ng t

ime

[sec

]