bof4957 hunt javaone rtsj bof 2014

8/17/2019 BOF4957 Hunt Javaone Rtsj Bof 2014

1/29

SR 282 BoF

The new

Real-Time Specifcation or ava

Dr. James J. Hunt

JSR 282 Spec ea!

Java"ne Septem#er 2$%&


2/29


3/29

,

eal-T'me Specifcation or ava 2.$

onstraints

o chan*es to the lan*ua*e

same #+teco!e

no new lan*ua*e eatures

Full+ compati#le with convention Java

implementations such as "penJD/

Java pro*rams shoul! run correctl+ on RTSJ

implementations that supports the re0uire! profle

1aimi3e co!e reuse un!er time compleit+

constraints


4/29&


(h+ 4p!ate the RTS )

5nvironment evolution

#etter realtime *ar#a*e collection

aster processors

Java %.& Java %.8→

6n!roi!

1ar7etin*

support !ierent levels o realtime

even or conventional Java implementations

eliminate nee! or J' or '9"


5/29:


RTS %.$.2 'ssues

Device memor+ access inefcient

Sin*le class or accessin* all precision or each ointe*ral an! ;oatin* t+pes

Raw1emor+6ccess

Raw1emor+Float6ccess

4nclear how '9" memor+ is a!!ress

flters un!er !efne!6ccess testin* on ever+ access

annot t+pe restrict memor+ access

Har! to inline


6/29<


RTS %.$.2 'ssues

Happenin* ill !efne!

o stan!ar! wa+ to a!! new happenin*s

Happenin*s not o#=ects

'nconsistent with other 6s+nc5vent t+pes

>"S'?

loc7

4ser tri**ere!

Too man+ levels o in!irection

Happenin* 6s+nc5vent 6s+nc5ventHan!ler→ →

o support or frst level interrupt han!lers


7/29@


RTS %.$.2 'ssues

o wa+ to !efne a new loc7

Scope!1emor+

o simple wa+ to use scopes or >ro!ucer-onsumer pattern

o wa+ to mana*e #ac7in* store

1ulticore

no wa+ to assi*n S"s to processors

1iscellaneous Defciencies


8/298eal-T'me Specifcation or ava 2.$

ew Raw 1emor+ 6rchitecture

Factor+Base!

Raw1emor+ class or re*istration

Raw1emor+Factor+ or implementation

'nteraces or each access t+pe

Raw'ntA RawShortA RawB+teA RawFloatA etc.

oncrete classes or

1emor+ mappe! !evicesA

'9" mappe! !evicesA an!

eneric mappe! !evices.


9/29Ceal-T'me Specifcation or ava 2.$

Raw1emor+ 'nteraces

javax.realtime::RawFloatWriter

«interface»

+setFloat(oat v)

+setFloat(int oset, oat data)+set(int oset, oat[] v): int

+set(int oset, oat[] v,

int start, int count): int

+address():long

javax.realtime::RawFloat

«interface»

javax.realtime::RawFloatReader

«interface»

+getFloat():oat

+getFloat(int oset):oat

+get(int oset, oat[] v): int

+get(int oset, oat[] v,


+address():long

javax.realtime::RawDoubleWriter

«interface»

+setDouble(double v)

+setDouble(int oset, double data)+set(int oset, double[] v): int

+set(int oset, double[] v,


+address():long

javax.realtime::RawDoubleReader

«interface»

+get():double

+getDouble(int oset):double

+get(int oset, double[] v): int

+get(int oset, double[] v,


+address():long

javax.realtime::RawDouble

«interface»

javax.realtime::RawByteWriter

«interface»

+set!te(b!te v)

+set!te(int oset, b!te v)+set(int oset, b!te[] v):int

+set(int oset, b!te[] v,

int start, int count):int

+address():long

javax.realtime::RawByte

«interface»

javax.realtime::RawByteReader

«interface»

+get!te():b!te

+get!te(int oset):b!te

+get(int oset, b!te[] v):int

+get(int oset, b!te[] v,


+address():long

javax.realtime::RawShortWriter

«interface»

+set"#ort(s#ort v)

+set"#ort(int oset, s#ort v)+set(int oset, s#ort[] v):int

+set(int oset, s#ort[] v,


+address():long

javax.realtime::RawShortReader

«interface»

+get"#ort():s#ort

+get"#ort(int oset):s#ort

+get(int oset, s#ort[] v):int

+get(int oset, s#ort[] v,


+address():long

javax.realtime::RawShort

«interface»

javax.realtime::RawIntWriter

«interface»

+set$nt(int v)

+set$nt(int oset, int v)+set(int oset, int[] v):int

+set(int oset, int[] v,


+address():long

javax.realtime::RawIntReader

«interface»

+get$nt():int

+get$nt(int oset):int

+get(int oset, int[] v):int

+get(int oset, int[] v,


+address():long

javax.realtime::RawInt

«interface»

javax.realtime::RawLongWriter

«interface»

+set%ong(long v)

+set%ong(int oset, long v)+set(int oset, long[] v):int

+set(int oset, long[] v,


+address():long

javax.realtime::RawLongReader

«interface»

+get%ong():long

+get%ong(int oset):long

+get(int oset, long[] v):int

+get(int oset, long[] v,


+address():long

javax.realtime::RawLong

«interface»

javax.realtime::RawMemory

«interface»

java.io::Cloable

«interface»

+close()

&isibilit!

+ ' ublic

' rotected

* ' acage


10/29%$


5ample

>u#lic class '"Busontroller implements RawShort

private 1emor+RawB+te comman!E

private 1emor+RawB+te ;a*E

private 1emor+RawShort a!!ressE private 1emor+Raw'nt !ataE

pu#lic int *etshort a!!ressG

a!!ress.puta!!ressGE

comman!.putR56DGE

while ;a*.*etG I D"5GE

return !ata.*etGE

...


11/29%%


D16 Support

Special actor+ or !irect #+te #uer

et #+te #uer that is visi#le D16 controller

1eans to *et a!!ress to pass to D16 controller

oul! #e use to implement '9" hannels

6!!itional #arrier t+pes

provi!e write visi#ilit+ across J' #oun!ar+

or supportin* D16 with !irect #+te #uers

oor!inatin* with Dou* eaJ5> %88 Java 1emor+ 1o!el 4p!ateG


12/29%2


5vent 6rchitecture

6#stract6s+nc5vent

6s+nc5vent

>"S'?Si*nal>"S'?RealtimeSi*nal

6ctive5vent6s+ncon*5vent

6s+nc"#=ect5vent

Happenin*

'SR

Timer

>erio!icTimer "neShotTimer


13/29

%,


1i an! 1atch

T+pes 6s+nc5vent 6s+ncon*5vent 6s+nc"#=ect5vent

6s+nc5ventHan!ler o pa+loa! o pa+loa! o pa+loa!

6s+ncon*5ventHan!ler 5vent 'D >a+loa! 5vent 'D

6s+nc"#=ect5ventHan!ler 5vent "#=ect 5vent "#=ect >a+loa!


14/29

%&


Timer States

disabled disabled

stopped

active

relative

absoluteabsolute

-> FALSE

stop

startDisabled

stop

-> TRUE

-> TRUE

stop

Any Call

-> IllegalStateException

nonexistant

new Timer(AbsoluteTime, ..)

destroy

OneShotTimer

fire

active

skip

OneShotTimer

fire and selfreschedule

PeriodicTimer

isRunning

-> TRUE

skip and selfreschedule

PeriodicTimer

isRunning

-> FALSE

isRunning

-> FALSE


getFireTime

new Timer(RelativeTime, ..)

RelativeTime

reschedule

reschedule

RelativeTime

reschedule

reschedule

AbsoluteTime

AbsoluteTime


startDisabled

IllegalStateException

start

getFireTime

-> absoluteTime

-> start +

relativeTime

getFireTime

startenable disable

absolute

enabledactive

relative

disabled

active

enableddisabled

relative

stopped

destroyed


15/29

%:


6#stract6s+nc5vent States

new AbstractAsyncEvent(..)

isRunning isRunning

-> FALSE-> TRUE

enable disable

enabled disablednonexistant


16/29

%<


Happenin* /in! o 6s+nc5vent

6s+nc5vent

>assive fre mechanismG

Runs all associate! event han!lers

4ser !efna#le

Happenin*s

supports active #ehavior too tri**er mechanismG

an have nee!sG !ispatcher to mana*e activit+

an #e tri**ere! rom outsi!e the K1


17/29

%@


Happenin* Se0uence


18/29

%8


4ser Defne! loc7s

i7e an 'SR

no active threa!

=ust tri**ers associate! Timers

1ana*es Tri**er Lueue

net set o Timers in priorit+ or!erG to tri**er

time or!ere! set o Timer sets

constant tri**er time or top net Timer

#oun! a!!in* an! !eletin*


19/29

%C


loc7 Se0uence Dia*ram


20/29

2$


Sleep with 6pplication loc7


21/29

2%


6fnit+

1ulticore control

ena#le pinnin* Threa!s an! 6s+nc5ventHan!lersto a su#set o processors.

support collective pinnin* w9>rocessin*roup>arameters

fn! out what processors an! processor su#sets

are availa#le or pinnin*

pinnin* to sin*le processors is alwa+s supporte!.

ortho*onal to all other RTSJ classes


22/29

22


ew Scope!1emor+ 6reas

>inne!1emor+

su#class o Scope!1emor+

similar to T 1emor+ ecept supports pinnin*

Stac7e!1emor+

su#class o Scope!1emor+ supports SJ 1o!elG

similar to T 1emor+ #ut reserves #ac7in* store

#ac7in* store rom parent when Stac7e!1emor+

entera#le onl+ rom 1emor+6rea where create!

resi3e to ma reserve! when no su# areaG


23/29

2,


Stac7e!1emor+ 5ample

estin* $

estin* $

Split 6 estin* 2

estin* %

Split B estin* %

Split 6 estin* %

estin* 2

Split estin* ,


24/29

2&


Small han*e

RealtimeThrea!

a!! waitForetReleaseG an! releaseG

or aperio!ic processin*

6s+nc5ventHan!ler

memor+ area entere! on each release

ol! #ehavior o#taine! #+ usin* >inna#le1emor+

Release>arameters

a!! #loc7in* actor to support easi#ilit+ anal+sis


25/29

2:


Small han*e

onsistenc+

provi!e or frin* an 6s+nc5vent or release an6s+nc5ventHan!lerG on all resource limit errors.

new metho!s as necessar+ to provi!e #oth areturne! o#=ect an! one that ta7es a !estinationA

e.*.A to reuse Hi*hResolutionTime o#=ects

up!ate semantics or cost enorcement to permit

a sche!ula#leMs >4 use to #e #oun! #+ its cost

parameter in each perio!

sot cost enorcement


26/29

2<


Small han*e

>h+sical1emor+

4p!ate !ocumentation to improve clarit+.

>hasin* control or perio!ic S"s

RelativeTime

a!! compareTo$G

a!! scaleint actorG

Time!

a!! resetG metho!

#etter support or watch!o* timers


27/29

2@


1o!ulari3ation oals

>rovi!e useul su#sets o the RTSJ

with an! without a realtime

with an! without !evice support

5ncoura*e more implementations

Har! realtimeA e.*.A or control s+stems

Sot realtimeA e.*. or s+stem monitorin*

o realtimeA e.*.A or !evelopment


28/29

28


1o!ules

Base

Sche!ula#les

>riorit+ 'nheritance

loc7

...

Device

Happenin*s

Raw1emor+

...

1emor+ 6rea

immortal

ph+sical

scope!

6!vance! "ptions

6T

>5

'SR


29/29

2Cicas m#H

ontact 'normation

Dr. ames . Hunt

aicas m#HHai!-un!-eu-Str. %8

D-@

bof4957 hunt javaone rtsj bof 2014

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