A survey of uC/OS & lwIP

A survey of uC/OS & lwIP

蔡嘉泰[email protected]

NETLAB

MicroC/OS II

NETLAB

Features

Source Code Open Source，程式碼簡潔易懂

Portable 程式碼大部分皆是利用 ANSI C所開發的與 microprocessor行為有關的則利用組合語言來完成，使得 uC/OS-II能夠輕易的移植到其他 Processor uC/OS-II可以在 8/16/32 bits 的 microprocessor上或是micro-controller上運作

NETLAB

Features

ROMable 只要有適當的工具 (C compiler, assembler and

linker/locator)就可將 uC/OS-II嵌入成為產品一部分 Scalable

可以很簡單的選用程式 /產品所需要的特性也就是說可以依照自己的需求減少程式的大小，以便可以放入 ROM/RAM中

NETLAB

HIGH Priority Task

LOW Priority TaskISR(1) (2)

(3)(4)

(5)

(6)

(7)

ISR makes the high priority task ready

Time

Features

Preemptive uC/OS-II 永遠會讓已經 Ready且優先權最高的工作行程先執行

NETLAB

TASKWAITING

TASKDORMANT

TASKREADY

TASKRUNNING

ISRRUNNING

Features

NETLAB

Features

Multi-tasking uC/OS-II最多可支援 64 個 task，其中會為系統保留8 個 task使用每一個 task都有一個唯一的 priority，也就是說

uC/OS-II無法實現 Round Robin排程

NETLAB

StatusSP

Priority...

Task Control Block

TASK #1Stack

SP

.

.

.

StatusSP

Priority...

Task Control Block

TASK #2Stack

StatusSP

Priority...

Task Control Block

TASK #nStack

……

MEMORYCPU

Features

NETLAB

Features

Deterministic 在 uC/OS-II內的各項服務所需要的執行時間都是可明確預先得知的

Task Stacks uC/OS-II允許每一個 task擁有不一樣的 stack size 根據需要增減 task 的 stack size減少 RAM的使用

NETLAB

Features

Services Mailbox, Queues, Semaphores, Fixed-sized

memory partitions, Time related function, etc. Interrupt Management

Interrupts can suspend the execution of a task 256 levels

Robust and Reliable

NETLAB

uC/OS-II移植分析只要有相對應的 C Compiler，即可將 uC/OS-II移植到特定的處理器上大部分移植工作都在多任務的切換上

用來儲存以及恢復 register的值利用組合語言完成

需修改的檔案 OS_CPU.H, OS_CPU_C.C, OS_CPU_A.S

NETLAB

OS_CPU.H

定義DATA TYPE 與所使用的 Compiler相關不同的 Compiler會使用不一樣的 byte來表示同一

DATA TYPE X86平台 , Integer:

• GNU (gcc): 4 bytes• MicroSoft (VC++): 2 bytes

NETLAB

OS_CPU.H

Stack Entry 定義 TASK 的 Stack長度，必須要和 CPU 的

Register的長度一致堆疊增長方向

定義 Stack grows from HIGH to LOW or Low to HIGH Memory

NETLAB

OS_CPU.H

NETLAB

OS_CPU.H

中斷、 Content Switch

NETLAB

OS_CPU_C.C

Initialize a Task‘s STACK 在堆疊增長的方向上定每一個需要保存的 Register位址

AXCXDXBXSPBPSIDIESDS

HIGH

LOW

NETLAB

OS_CPU_C.C

NETLAB

OS_CPU_A.S

OSStartHighRdy( ) 在 OSStart()啟動之後，負責從最高優先權任務的

TCB Control Block中獲得該任務的 Stack Point (SP)

OSCtxSw( ) 將前一 task 的 register保存到堆疊中，獲得最高優先

權 task 的 SP，將此 task 的 register恢復，使之繼續執行 OSIntCtxSw( )

中斷級的 Content Switch

NETLAB

Handbook

NETLAB

Hardware Abstraction Layer (HAL) Real-time kernel Interrupt handling Exception handling Choice of schedulers Thread support Rich set of synchronization primitives Timers, counters and alarms Choice of memory allocators Debug and instrumentation support

μITRON 3.0 compatible API POSIX compatible API ISO C and math libraries Serial, ethernet, wallclock and watchdog device drivers USB slave support TCP/IP networking stacks GDB debug support

NETLAB

light weight IP (lwIP)

NETLAB

lwIP簡介 lwIP一套可用於 embedded system 的 TCP/IP

protocol lwIP可以移植到各OS上，在沒有OS情形下也可以獨立運作

lwIP主要是為了保持 TCP Protocol的主要功能並減少對 RAM的使用

只需要幾十 K 的 RAM和約 40K 的 ROM就可以運作，使得 lwIP很適合在嵌入式系統中運作

NETLAB

lwIP簡介

嵌入式系統開發板

lwIP (TCP/IP Protocol)

uC-OS II

Upper Layer Protocol (ULP)

NETLAB

lwIP特性 IP including packet forwarding over multiple

network interfaces ICMP for network maintenance and

debugging UDP for datagram data TCP with congestion control, RTT estimation

and fast recovery/fast retransmit Specialized no-copy API for enhanced

performance Optional Berkeley socket API

NETLAB

lwIP特性 lwIP將所有與硬體、OS 、 Compiler相關的部分獨立出來放置在 /src/arch下修改這一些相關檔案將 lwIP移植到 uC/OS-II上

NETLAB

Application/ Management model

Protocol Stack

RTP, RTCP

UDP

IP

MAC

Physical

NETLAB

TCP/IP與行程間的溝通

NETLAB

SOCKET APIbindlistenconnectacceptrecvsendwriteclose

lwip_APIlwip_bindlwip_listenlwip_connectlwip_acceptlwip_recvlwip_sendlwip_writelwip_close

netconn_APInetconn_bindnetconn_listennetconn_connectnetconn_acceptnetconn_recvnetconn_sendnetconn_writenetconn_close

NETLAB

application

socket API

lwip_bind …

netconn_bind …

driver

recv_buf_data

ethernetif_input

low_level_inpit

ip_input

tcp_input

tcp_process

tcpip_thread

api_msg_input

do_bind …

TASK 1 TASK 2 TASK 3

NETLAB

TASK 1(application 1) TASK 2

(data input)

TASK 3(tcpip_thread)

mboxrecvmbox acceptmbox

Single Application

NETLAB

TASK 2(data input)

TASK 3(tcpip_thread)

mbox

TASK 1(application 1)

recvmbox acceptmbox

TASK N(application N)

recvmbox acceptmbox

Multi Application

NETLAB

API types

TYPE 1 BIND, LISTEN, CLOSE

TYPE 2 CONNECT

TYPE 3 SEND. WRITE

TYPE 4 ACCEPT, RECV

NETLAB

TASK 1

TYPE 1

TASK 2mbox1 2

34

msg->type• API_MSG_BIND• API_MSG_LISTEN

NETLAB

netconn_bind do_bindAPI_MSG_BIND

netconn_bind

mboxapi_msg_post sys_mbox_fetch

sys_mbox_postsys_mbox_fetch

tcp_bind

NETLAB

netconn_listen do_listenAPI_MSG_LISTEN

netconn_listen



pcb->accpet = accept_function

NETLAB

netconn_close do_closeAPI_MSG_CLOSE

netconn_close



tcp_close

NETLAB

TYPE 2

TASK 1

TASK 2

mbox1

2msg->type• API_MSG_CONNECT

TASK 3

34

NETLAB

netconn_connect

do_connect

pcb->connected = do_connectedpcb->state = SYN_SENTtcp_enqueue()tcp_output()

netconn_connect

tcp_input() , tcp_process()switch case: SYNSENTpcb->connected

do_connected

mboxapi_msg_post

sys_mbox_fetch

sys_mbox_post

sys_mbox_fetch

NETLAB

TYPE 3

TASK 1 mbox1 2

34

msg->type• API_MSG_SEND• API_MSG_WRITE

TASK 2

udp_outputor

tcp_write

NETLAB

netconn_send do_sendAPI_MSG_SEND

netconn_send



udp_output

NETLAB

netconn_write do_writeAPI_MSG_WRITE

netconn_write



tcp_enqueuetcp_output

NETLAB

TYPE 4

TASK 3TASK 112 acceptmbox

orrecvmbox

TASK 2mbox3 4

56

msg->type• API_MSG_RECV

NETLAB

netconn_accept

in tcp_processpcb->accept

accept_functionnetconn_accept acceptmboxsys_mbox_postsys_mbox_fetch

NETLAB

netconn_recv

recv_tcpnetconn_recv recvmbox

do_recvmboxAPI_MSG_RECV

in tcp_input()pcb->recv


api_msg_post sys_mbox_fetch


Let the stack know that we have taken the data

NETLAB

Server

netconn_new

netconn_bind

netconn_listen

netconn_accept

netconn_recv

netconn_write

netconn_close

do_bind

do_listen

accept_function

recv_tcp

do_write

do_recv

do_close

mbox

acceptmbox

recvmbox

mbox

mbox

mbox

mbox


NETLAB

Client

netconn_new

netconn_bind

netconn_connect

netconn_recv

netconn_write

netconn_close

do_bind

do_connect

do_connected

recv_tcp

do_write

do_recv

do_close

mbox

recvmbox

mbox

mbox

mbox

mbox


An Implementation of RDMA

Student: Chia-Tai TsaiAdviser: Prof. Rong-Hong Jan

NETLAB

Introduction 1/3

Network bandwidth bottlenecks Network hardware Network Protocol Performance End station performance

• CPU• The I/O bottlenecks

– Interrupts– TCP/IP checksum– Copies

NETLAB

DMA

NETLAB

RDMA

NETLAB

Protocol Stack

NETLAB

Experimental Model

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Documents

A survey of uC/OS & lwIP