8. ThreadX-presentation TN

8/18/2019 8. ThreadX-presentation TN

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Group members:Huynh Trung ManhPham Hung Thinh

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Contents• ThreadX Unique Features• Embedded Applications•

ThreadX benefts• Functional Components o ThreadX

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ThreadX Unique Features• "ico#ernel Architecture• A$%& C source code•

$ot a blac# bo'• A potential stantard

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ThreadX Unique Features• "ico#ernel Architecture

– ser(ices are implemented as a C librar) – onl) ser(ices actuall) used are brou*ht

into the run+time ima*e – ser(ices plu* directl) into its core ,-

astest possible conte't s.itchin* and

ser(ice call per ormance

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ThreadX Unique Features• A$%& C source code

– .ritten primaril) in A$%& C – A small amount o assembl) lan*ua*e is

needed to tailor the #ernel to theunderl)in* tar*et processor

possible to port ThreadX to a ne.processor amil) in a (er) short time

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ThreadX Unique Features• $ot a blac# bo'

– ost distributions include the completeC source code 4 the processor+specifcassembl) lan*ua*e

see e'actl) .hat the #ernel is doin*

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ThreadX Unique Features• A potential standard

– 5ersatilit) – i*h+per ormance pico#ernel

architecture – "ortabilit)

potential to become an industr)standard or embedded applications

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Embedded Applications• 8eal+time so t.are• ultitas#in*•

Tas#s and Threads

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Embedded Applications• 8eal+time so t.are

– interaction .ith the e'ternal .orld•

ultitas#in* – the allocation o the processor bet.eenthe (arious application tas#s

– the primar) purpose o ThreadX

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Embedded Applications• Tas#s and Threads

– Tas#• sometimes means a separatel) loadable

pro*ram• &n other instances; it mi*ht re er to an internal

pro*ram se*ment – Thread

• A semi+independent pro*ram se*ment thate'ecutes .ithin a process

• %hare the same process address space• The o(erhead associated .ith thread

mana*ement is minimal

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ThreadX benefts• &mpro(ed responsi(eness

– preempti(e; priorit)+based schedulin*al*orithm

• %o t.are maintenance – Enables de(elopers to concentrate on

specifc requirements o their applicationthreads .ithout ha(in* to .orr) aboutchan*in* the timin* o other areas othe application

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ThreadX benefts• &ncreased throu*hput

– multi+threadin* actuall) reduceso(erhead b) eliminatin* all o theredundant pollin*

• "rocessor isolation – robust processor+independent inter ace

bet.een the application and theunderl)in* processor

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ThreadX benefts•


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ThreadX benefts• &mpro(e time+to+mar#et

– ThreadX ta#es care o most processorissues

• "rotectin* the so t.are in(estment – ThreadX insulates applications rom

details o the underl)in* processors hi*hl) portable

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Functional Components o ThreadX

• E'ecution o(er(ie.• &nitiali=ation•

Thread E'ecution• Application timers• emor) usa*e• &nterrupts

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E'ecution o(er(ie.

&nitiali=ation

ThreadE'ecutio

n

&%8 Application timers

ard.are 8eset

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&nitiali=ation

ain>?

t'@#ernel@enter>?

t'@application@defne>mem @ptr?

Enter thread %chedulin* loop

int main>? /B Enter the ThreadX #ernelB/ t'@#ernel@enter>? D

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t'@thread@create

t'@mute'@create


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Thread E'ecution

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Terminated %tate

Completed

%tate

E'ecutin* %tate

%uspended %tate

8ead)%tate

T'@thread@create

TX@AUT @%TA8T TX@< $ T@%TA8T

Threadschedulin*


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Thread priorities

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Highest Lowest

• Threads can ha(e the same priorit) as others in theApplication

• Thread priorities can be chan*ed durin* run+time

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Thread %chedulin*

• & multiple threads o the same priorit) G• F&F• Time+slicin*

• A time+slice specifes the ma'imumnumber o timer tic#s >timerinterrupts?

•

The thread s time+slice is assi*neddurin* creation and can be modifeddurin* run+time

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Thread %chedulin*• "reemption causin* G

+ star(ation

+ e'cessi(e conte't s.itchin*o(erhead + priorit) in(ersion

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Thread %chedulin*• "reemption+threshold

Hhat is apreempti

on+threshold

I

speci ) a priorit) ceilin*

or disablin* preemption

i*herpriorities > The ceiling Jo.er priorities>

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E'ampleI


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Application timers• applications .ith the abilit) to

e'ecute application C unctions atspecifc inter(als o timers

• Usin* timer interrupt >timer tic#s?10ms

• o. to *enerate periodic interrupts IUnderl)in*hard.are

peripheralde(iceinterrupts

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emor) Usa*e

&nstruction Area8

Constant Area8

&nitiali=ed


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emor) Usa*e


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Another componnents

&nterrupt

emor)Nloc#"ools E(entFla*s ute'es

%emaphores

essa*eOueues

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Q !

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Documents

8. ThreadX-presentation TN