ixp lab 2012: part 1

IXP Lab 2012: Part 1

Network Processor Brief

NCKU CSIE CIAL Lab 2

Outline Network Processor Intel IXP2400

Processing Element Register Memory Interface

IXP Programming Language Programming Model Programming Syntax


Router Development (1)

Software Based General Purpose Processor

Flexible Poor Performance …

Hardware Based ASIC

Best Performance Long Development Time


Router Development (2)

Network Processor (NPU) Based Balance of both How ?

Parallel processors Multi-threaded cores Programmable processors with

nonprogrammble copressors


Network Processor Overview

For high speed packet processing Comprise Multi-Cores for Parallel

executing Multi-Threaded Core Reduced Instruction Set Multiple Memory Interfaces


Hierarchical Layer Data-Plane

Fast-Path Slow-Path

Control-Plane Routing Protocol

Management-Plane Monitor Applications User Interface


Data-Plane

Fast-Path General Packet Handling As fast as possible

Slow-Path Exception Packet Handling

Packet with options Local TCP/IP Stack


Internet eXchange Processor First Generation

IXP1200, IXP1240, IXP1250 Second Generation

IXP2400, IXP2800, IXP2850 IXP2805, IXP2855

Others IXP4XX


Network Flow Processor

By Netronome From Intel IXP2XXX NFP-3240, NFP-3216


Intel IXP2400 Block Diagram


IXP2400 Overview

Functional Block Processing Element Memory Interfaces Coprocessors Other Interfaces

Hierarchical View


Processing Element

Programmability Hierarchical Processing Elements

XScale Microengine (ME)


XScale

RISC based processor (ARMV5TE) Real-time OS

Montavista Linux ME Management

Control ME execution Resource Management


MicroEngine (1)

Eight MEs per IXP2400 (work in parallel)

Eight Threads per ME Instruction set of ME are reduced

for packet processing only Not as powerful as general processor No floating point related instructions No divide instruction


MicroEngine (2)

No OS Not interactive Managed by XScale

Code Store (4K Instrcutions) Executing


MicroEngine Threads

Concurrent Executing No Preemptive Round Robin Executing Each thread own its private set of

registers Zero-Overhead Context Switching


Registers of ME 256 GPRs 256 SRAM Transfer Registers

128 Read 128 Write

256 DRAM Transfer Registers 128 Read 128 Write

128 Next Neighbor Registers


Context Switch

Content of registers needs not be swap-out and swap-in during context switching

With the mechanism, another thread can swap in and doing some useful task to cover the long latency when the previous thread has swapped out for issues a memory request


Memory Interface of IXP2400 Local Memory

Smallest and Fastest Scratchpad

Passing handle of the packet SRAM

Hold data structure for packet processing DRAM

Largest and Slowest Hold packet’s content


Local Memory Per ME Private to Other MEs Private to XScale Size: 2560 Bytes (640 LWs) Usage

Variable Spilling Caching

Latency: 3 cycles


Scratchpad

On-Chip Memory Shared by all MEs Size: 16KB (Fixed) Usage:

Scratchpad Scratch Ring (Hardware FIFO)

Latency: ~60 cycles


SRAM Off-Chip Memory Shared by all MEs (2-channels) Size: 64 MB (Per Channel at

Maximum) Usage:

Hardware FIFO Hold data structure Hold Meta-data of packets

Latency: ~90 cycles


DRAM

Off-Chip Memory Shared by all MEs (1-channels) Size: 1 GB (at Maximum) Usage:

Hold whole packet contents Alternative space for data structure

Latency: ~120 cycles


Coprocessor MSF (Media Switch Fabric)

Receive Packet to DRAM Transmit Packet from DRAM

SHaC Scratchpad Hash Unit CAP


Packet META-DATA (1)

Data for processing packets How to identify packet?

Packet Handle Packet Temporal Information

Non-related to packet content Meta-data

Input Port, Output Port Info for Packet Address in DRAM


Packet META-DATA (2)

How to pass these info between ME? Hardware FIFO

Scratch Ring SRAM Ring Next-Neighbor Ring

Issues


Hierarchical View (Setting #1) Only one IXP2400 based board Data-Plane

Fast-Path: Microengine Slow-Path: XScale

Control-Plane XScale

Management-Plane XScale


Hierarchical View (Setting #2) Multiple IXP2400 based boards Data-Plane

Fast-Path: Microengine Slow-Path: XScale

Control-Plane CPU

Management-Plane CPU


Programming IXP2400

XScale Programming with C

Microengine Programming with MicroC or

Microcode We will focus on this part !


IDE Tool--IXA SDK Workbench


ME Language

MicroC Subset of ANSI C Only limited part of standard C

libraries are implemented Intrinsic Library for supporting

operations of IXP Microcode

High level of assembly


Programming Model (1)

Receive – Processing – Transmit Intel has provided sample code for

receive and transmit. We only focus on the part of

processing.

RX PROCESSING TX


Programming Model (2)

Processing ME Pipeline Model Parallel Model Mixed Model

RX PROCESSING TX


Pipeline Model

RX TXPROC #1 RPOC #2

•Control the whole resource of ME

•Hard to balance between different stage


Parallel Model

RX TX

PROC #1

RPOC #2

•Balance is easy

•Higher Performance

•Resource is limited


Mixed Model

RX TX

PROC #1

RPOC #2

PROC #3


MicroC Example 1 (1)void main () {

_declspec(shared sram) int old_array[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };_declspec(shared sram) int new_array[sizeof(old_array)/sizeof(int)];

global_label("start_reverse");reverse_array(old_array, new_array,

sizeof(old_array)/sizeof(int));global_label("end_reverse");

}


MicroC Example 1 (2)

void reverse_array(volatile int* old, volatile int* new, int

size) { int index = 0;

for (index = 0; index < size; index++) {new[index] = old[size - index - 1];

}}


MicroC Example 2

sram_read(&sram_egt_dim1_2_node, (__declspec(sram) unsigned int *)(PACKET_CLASSIFICATION_SRAM_BASE1 + current*8), 2, sig_done, &sram_read_sig_dim1_2);

__wait_for_all(&sram_read_sig_dim1_2);temp = sram_egt_dim1_2_node.next_dim;


1. COPY IXA_SDK_3.51, ixp_book 到 D:\ ; 再 reboot

3.[Ctrl+Enter] 進還原卡總管模式 4.Password: davidchang 5. 解壓縮 ixasdk351cd1windows.zip,

ixasdk351cd3.zip, ixasdk351framework.zip, 再依序安裝 (cd1 裝完後需 reboot)

6. 把 ixp_book 目錄 COPY 到 C:\

ixp lab 2012: part 1

Documents

ixp lab

router development

packet processing onlynot

packet processingdraml

pathgeneral packet handlingas

ixp2400 work

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