cpu schedulin… · (chapter 6: “scheduling” up to page 458) performance scheduling round robin...
TRANSCRIPT
433
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
433
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Defi
nit
ion
of t
erm
s
Tim
e sc
ales
of s
ched
ulin
g
CPU
ydaer
read
y, s
usp
end
ed
blo
cked
, su
spen
ded
blo
ckedp
re-e
mp
tio
n o
r cy
cle
do
ne
blo
ck o
r sy
nch
ron
ize
exec
uti
ng
dis
pat
ch susp
end
(sw
ap-o
ut)
swap
-in
swap
-out
un
blo
ck
susp
end
(sw
ap-o
ut)
Short-term
Med
ium-term
430
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
430
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Mot
ivat
ion
and
defi
niti
on o
f ter
ms
Purp
ose
of s
ched
ulin
g
Two
sce
nar
ios
for
sch
edu
ling
algo
rith
ms:
1. O
rder
ing
reso
urc
e as
sign
men
ts (C
PU ti
me,
net
wo
rk a
cces
s, …
). l
ive,
on
-lin
e ap
plic
atio
n o
f sch
edu
ling
algo
rith
ms.
2. P
red
icti
ng
syst
em b
ehav
iou
rs u
nd
er a
nti
cip
ated
load
s. s
imu
late
d, o
ff-l
ine
app
licat
ion
of s
ched
ulin
g al
gori
thm
s.
Pred
icti
on
s ar
e u
sed
:
• at
co
mp
ile t
ime:
to c
on
fi rm
the
feas
ibili
ty o
f th
e sy
stem
, or
to p
red
ict r
eso
urc
e n
eed
s, …
• at
ru
n t
ime:
to p
erm
it a
dm
itta
nce
of n
ew r
equ
ests
or
for
load
-bal
anci
ng,
…
427
6Sc
hedu
ling
Uw
e R
. Zim
mer
- T
he A
ustr
alia
n N
atio
nal U
nive
rsity
Syst
ems,
Net
wo
rks
& C
on
curr
ency
201
9
434
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
434
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Defi
nit
ion
of t
erm
s
Tim
e sc
ales
of s
ched
ulin
g
CPU
crea
tio
ny
daerhcta
b
read
y, s
usp
end
ed
blo
cked
, su
spen
ded
blo
ckedp
re-e
mp
tio
n o
r cy
cle
do
ne
term
inat
e.
blo
ck o
r sy
nch
ron
ize
exec
uti
ng
adm
it
dis
pat
ch susp
end
(sw
ap-o
ut)
swap
-in
swap
-out
un
blo
ck
susp
end
(sw
ap-o
ut)
Long
-term
Short-term
Med
ium-term
431
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
431
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Mot
ivat
ion
and
defi
niti
on o
f ter
ms
Cri
teri
a
Perf
orm
ance
cri
teri
a:Pr
edic
tabi
lity
crit
eria
:
Pro
cess
/ u
ser
per
spec
tive
:
min
imiz
e th
e …
min
imiz
e d
evia
tio
n fr
om
giv
en …
Wai
ting
tim
em
inim
a / m
axim
a / a
vera
ge /
vari
ance
valu
e / m
inim
a / m
axim
a
Res
pons
e ti
me
min
ima
/ max
ima
/ ave
rage
/ va
rian
ceva
lue
/ min
ima
/ max
ima
/ dea
dlin
es
Turn
arou
nd t
ime
min
ima
/ max
ima
/ ave
rage
/ va
rian
ceva
lue
/ min
ima
/ max
ima
/ dea
dlin
es
Syst
em p
ersp
ecti
ve: m
axim
ize
the
…
Thro
ughp
utm
inim
a / m
axim
a / a
vera
ge
Uti
lizat
ion
CPU
bu
sy ti
me
428
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
428
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Ref
eren
ces
for
this
cha
pter
[ Ben
2006
] B
en-A
ri, M
Pr
inci
ple
s o
f Co
ncu
rren
t an
d D
is-
trib
ute
d P
rogr
amm
ing
seco
nd
ed
itio
n, P
ren
tice
-Hal
l 200
6
[Ad
aRM
2012
]A
da
Refe
ren
ce M
anu
al -
Lan
-gu
age
and
Sta
nd
ard
Lib
rari
es;
ISO
/IEC
865
2:20
1x (E
)
[ Sta
lling
s200
1 ] St
allin
gs, W
illia
m
Op
erat
ing
Syst
ems
Pren
tice
Hal
l, 20
01
435
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
435
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Req
uest
ed r
eso
urce
tim
es
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Task
s h
ave
an a
vera
ge t
ime
betw
een
inst
anti
atio
ns o
f T
i
and
a c
on
stan
t com
puta
tion
tim
e o
f C
i
432
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
432
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Defi
nit
ion
of t
erm
s
Tim
e sc
ales
of s
ched
ulin
g
CPU
ydaer b
lock
edpre
-em
pti
on
or
cycl
e d
on
e
blo
ck o
r sy
nch
ron
ize
exec
uti
ng
dis
pat
ch
Short-term
429
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
429
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Mot
ivat
ion
and
defi
niti
on o
f ter
ms
Purp
ose
of s
ched
ulin
g
442
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
442
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Sho
rtes
t jo
b fi
rst
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..11,
ave
rage
: 3.7
– T
urna
roun
d ti
me:
1..1
4, a
vera
ge: 6
.3
Op
tim
ized
for
goo
d a
vera
ge p
erfo
rman
ce w
ith
min
imal
task
-sw
itch
es.
Pre
fers
sh
ort
task
s b
ut a
ll ta
sks
will
be
han
dle
d.
Goo
d ch
oice
if c
ompu
tati
on t
imes
are
kno
wn
and
task
sw
itch
es a
re e
xpen
sive
!
439
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
439
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Feed
bac
k w
ith
2i p
re-e
mp
tio
n in
terv
als
• Im
ple
men
t mu
ltip
le
hie
rarc
hic
al r
ead
y-q
ueu
es.
• Fe
tch
pro
cess
es fr
om
the
hig
hes
t fi ll
ed r
ead
y q
ueu
e.
• D
isp
atch
mo
re C
PU ti
me
for
low
er p
rio
riti
es (
2i un
its)
.
Pro
cess
es o
n lo
wer
ran
ks
may
su
ffer
sta
rvat
ion.
New
an
d s
ho
rt ta
sks
will
be
pre
ferr
ed.
CPU
pri
ori
ty 0
pri
ori
ty 1
exec
uti
ng
adm
it
dis
pat
ch 2
0
pri
ori
ty i
dis
pat
ch 2
1
dis
pat
ch 2
i
436
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
436
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Firs
t co
me,
fi rs
t se
rved
(FC
FS)
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..11,
ave
rage
: 5.9
– T
urna
roun
d ti
me:
3..1
2, a
vera
ge: 8
.4
As
task
s ap
ply
co
ncu
rren
tly
for
reso
urc
es, t
he
actu
al s
equ
ence
of a
rriv
al is
no
n-d
eter
min
isti
c. h
ence
eve
n a
det
erm
inis
tic
sch
edu
ling
sch
ema
like
FCFS
can
lead
to d
iffe
ren
t ou
tco
mes
.
443
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
443
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Sho
rtes
t jo
b fi
rst
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..10,
ave
rage
: 3.4
– T
urna
roun
d ti
me:
1..1
4, a
vera
ge: 6
.0
Can
be
sen
siti
ve to
no
n-d
eter
min
isti
c ar
riva
l seq
uen
ces.
440
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
440
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Feed
bac
k w
ith
2i p
re-e
mp
tio
n in
terv
als
- se
que
ntia
l tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..5, a
vera
ge: 1
.5 –
Tur
naro
und
tim
e: 1
..21,
ave
rage
: 5.7
Op
tim
ized
for
swif
t in
itia
l res
po
nse
s.
Pre
fers
sh
ort
task
s an
d lo
ng
task
s ca
n s
uff
er s
tarv
atio
n.
Ver
y sh
ort
init
ial r
espo
nse
tim
es! a
nd
go
od
ave
rage
turn
aro
un
d ti
mes
.
437
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
437
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Firs
t co
me,
fi rs
t se
rved
(FC
FS)
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..11,
ave
rage
: 5.4
– T
urna
roun
d ti
me:
3..1
2, a
vera
ge: 8
.0
In
this
exa
mp
le:
the
aver
age
wai
tin
g ti
mes
var
y b
etw
een
5.4
an
d 5
.9th
e av
erag
e tu
rnar
ou
nd
tim
es v
ary
bet
wee
n 8
.0 a
nd
8.4
Sho
rtes
t po
ssib
le m
axim
al t
urna
roun
d ti
me!
444
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
444
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Hig
hest
Res
po
nse
Rat
ion
CW
Ci
ii
+ F
irst
(HR
RF)
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..9, a
vera
ge: 4
.1 –
Tur
naro
und
tim
e: 2
..13,
ave
rage
: 6.6
Ble
nd
bet
wee
n S
ho
rtes
t-Jo
b-F
irst
an
d F
irst
-Co
me-
Firs
t-Se
rved
.
Pre
fers
sh
ort
task
s b
ut l
on
g ta
sks
gain
pre
fere
nce
ove
r ti
me.
Mor
e ta
sk s
wit
ches
and
wor
se a
vera
ges
than
SJF
but
bet
ter
uppe
r bo
unds
!
441
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
441
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Feed
bac
k w
ith
2i p
re-e
mp
tio
n in
terv
als
- ov
erla
pp
ing tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..3, a
vera
ge: 0
.9 –
Tur
naro
und
tim
e: 1
..45,
ave
rage
: 7.7
Op
tim
ized
for
swif
t in
itia
l res
po
nse
s.
Pre
fers
sh
ort
task
s an
d lo
ng
task
s ca
n s
uff
er s
tarv
atio
n.
Lon
g ta
sks
are
dela
yed
unti
l all
queu
es r
un e
mpt
y!
438
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
438
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Roun
d R
ob
in (R
R)
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..5, a
vera
ge: 1
.2 –
Tur
naro
und
tim
e: 1
..20,
ave
rage
: 5.8
Op
tim
ized
for
swif
t in
itia
l res
po
nse
s.
“St
retc
hes
ou
t” lo
ng
task
s.
Bou
nd m
axim
al w
aiti
ng t
ime!
(d
epen
ded
on
ly o
n th
e n
um
ber
of t
asks
)
451
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
451
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Co
mp
aris
on
over
view
Sele
ctio
nPr
e-em
pti
on
Wai
tin
gTu
rnar
ou
nd
Pref
erre
d
job
sSt
arva
tio
n
po
ssib
le?
Met
ho
ds
wit
ho
ut a
ny
kno
wle
dge
ab
ou
t th
e p
roce
sses
FCFS
()
max
Wi
no
lon
glo
ng
aver
age
&
sho
rt m
axim
um
equ
aln
o
RR
equ
al s
har
eye
sb
ou
nd
goo
d a
vera
ge &
la
rge
max
imu
msh
ort
no
FBp
rio
rity
q
ueu
esye
sve
ry s
ho
rtsh
ort
ave
rage
&
lon
g m
axim
um
sho
rtn
o
Met
ho
ds
emp
loyi
ng
com
pu
tati
on
tim
e C
i an
d e
lap
sed
tim
e E i
SJF
()
min
Ci
no
med
ium
med
ium
sho
rtye
s
HR
RF
()
max
CW
Ci
ii
+n
oco
ntr
olla
ble
co
mp
rom
ise
con
tro
llab
le
com
pro
mis
eco
ntr
olla
ble
no
SRTF
()
min
CE
ii
-ye
sve
ry s
ho
rtw
ide
vari
ance
sho
rtye
s
448
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
448
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Co
mp
aris
on
by s
hort
est
aver
age
wai
ting
tim
e0
510
1520
2530
3540
45
FCFS
FCFS
RR
FB-
seq
.
FB-
ovl
p
SJF
SJF
HR
RF
SRTF
Pro
vid
ing
sho
rt a
vera
ge w
aiti
ng
tim
es
Ver
y sw
ift r
esp
on
se in
mo
st c
ases
Wai
tin
g ti
mes
Turn
aro
un
d ti
mesAve
rage
s
445
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
445
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Sho
rtes
t Re
mai
ning
Tim
e Fi
rst
(SRT
F)
tim
e0
510
1520
2530
3540
45(T
i, C
i)
(4, 1
)
(12,
3)
(16,
8)
Wai
ting
tim
e: 0
..6, a
vera
ge: 0
.7 –
Tur
naro
und
tim
e: 1
..21,
ave
rage
: 4.4
Op
tim
ized
for
goo
d a
vera
ges.
Pre
fers
sh
ort
task
s an
d lo
ng
task
s ca
n s
uff
er s
tarv
atio
n..
Bet
ter
aver
ages
tha
n Fe
edba
ck s
ched
ulin
g bu
t w
ith
long
er a
bsol
ute
wai
ting
tim
es!
452
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
452
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Pred
icta
ble
sche
dulin
g
Tow
ard
s p
red
icta
ble
sch
edul
ing
…
Task
req
uir
emen
ts (Q
ual
ity
of s
ervi
ce):
Gu
aran
tee
data
fl ow
leve
ls
Gu
aran
tee
reac
tion
tim
es
Gu
aran
tee
dead
lines
Gu
aran
tee
deliv
ery
tim
es
Pro
vid
e bo
unds
for
the
vari
atio
ns in
res
ult
s
Exam
ple
s:
• St
ream
ing
med
ia b
road
cast
s, p
layi
ng
HD
vid
eos,
live
mix
ing
aud
io/v
ideo
, …
• R
eact
ing
to u
sers
, Rea
ctin
g to
ala
rm s
itu
atio
ns,
…
• D
eliv
erin
g a
sign
al to
the
ph
ysic
al w
orl
d a
t th
e re
qu
ired
tim
e, …
449
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
449
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Co
mp
aris
on
by s
hort
est
max
imal
tur
naro
und
tim
e0
510
1520
2530
3540
45
FCFS
FCFS
RR
FB-
seq
.FB
-o
vlp
SJF
SJF
HR
RF
SRTF
Pro
vid
ing
up
per
bo
un
ds
to tu
rnar
ou
nd
tim
es
No
task
s ar
e le
ft b
ehin
d
Wai
tin
g ti
mes
Turn
aro
un
d ti
mesAve
rage
s
446
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
446
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Co
mp
aris
on
(in o
rder
of a
pp
eara
nce)
tim
e0
510
1520
2530
3540
45
FCFS
FCFS
RR
FB-
seq
.FB
-o
vlp
SJF
SJF
HR
RF
SRTF
Wai
tin
g ti
mes
Turn
aro
un
d ti
mesAve
rage
s
453
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
453
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Pred
icta
ble
sche
dulin
g
Tem
po
ral s
cop
es
Co
mm
on
att
rib
ute
s:
• M
inim
al &
max
imal
de
lay
afte
r cr
eati
on
• M
axim
al e
laps
ed t
ime
• M
axim
al e
xecu
tion
tim
e
• A
bso
lute
dea
dlin
eTa
sk i
t1
0352
025
10
dea
dlin
e
min
. del
aym
ax. d
elay
crea
ted
max
. ela
pse
tim
em
ax. e
xec.
tim
e
450
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
450
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Co
mp
aris
on
by s
hort
est
aver
age
turn
aro
und
tim
e0
510
1520
2530
3540
45
FCFS
FCFS
RR
FB-
seq
.
FB-
ovl
p
SJF
SJF
HR
RF
SRTF
Pro
vid
ing
goo
d a
vera
ge p
erfo
rman
ce
Hig
h th
rou
ghp
ut s
yste
ms
Wai
tin
g ti
mes
Turn
aro
un
d ti
mesAve
rage
s
447
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
447
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Perf
orm
ance
sch
edul
ing
Co
mp
aris
on
by s
hort
est
max
imal
wai
ting
tim
e0
510
1520
2530
3540
45
FCFS
FCFS
RR
FB-
seq
.FB
-o
vlp
SJF
SJF
HR
RF
SRTF
Pro
vid
ing
up
per
bo
un
ds
to w
aiti
ng
tim
es
Sw
ift r
esp
on
se s
yste
ms
Wai
tin
g ti
mes
Turn
aro
un
d ti
mesAve
rage
s
457
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
457
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Pred
icta
ble
sche
dulin
g
Co
mm
on
tem
po
ral s
cop
e at
trib
utes
Tem
pora
l sco
pes
can
be:
Peri
odic
co
ntr
olle
rs, r
ou
ters
, sch
edu
lers
, str
eam
ing
pro
cess
es, …
Ape
riod
ic p
erio
dic
‘on
ave
rage
’ tas
ks, i
.e. r
egu
lar
bu
t no
t rig
idly
tim
ed, …
Spor
adic
/ T
rans
ient
use
r re
qu
ests
, ala
rms,
I/O
inte
ract
ion
, …
Dea
dlin
es c
an b
e:
“Har
d” s
ingl
e fa
ilure
lead
s to
sev
ere
mal
fun
ctio
n a
nd
/or
dis
aste
r
“Fir
m”
res
ult
s ar
e m
ean
ingl
ess
afte
r th
e d
ead
line
on
ly m
ult
iple
or
per
man
ent f
ailu
res
lead
to m
alfu
nct
ion
“Sof
t” r
esu
lts
are
still
use
ful a
fter
the
dea
dlin
e
© 2
019
Uw
e R
. Zim“
Semantics defi ned by application
454
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
454
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Pred
icta
ble
sche
dulin
g
Tem
po
ral s
cop
es
Co
mm
on
att
rib
ute
s:
• M
inim
al &
max
imal
de
lay
afte
r cr
eati
on
• M
axim
al e
laps
ed t
ime
• M
axim
al e
xecu
tion
tim
e
• A
bso
lute
dea
dlin
eTa
sk i
t1
0352
025
10
dea
dlin
e
min
. del
aym
ax. d
elay
acti
vate
dcr
eate
d
max
. ela
pse
tim
em
ax. e
xec.
tim
e
458
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
458
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Sum
mar
y
Sche
dul
ing
• B
asic
per
form
ance
sch
edul
ing
• M
oti
vati
on
& T
erm
s
• Le
vels
of k
no
wle
dge
/ as
sum
pti
on
s ab
ou
t th
e ta
sk s
et
• Ev
alu
atio
n o
f per
form
ance
an
d s
elec
tio
n o
f ap
pro
pri
ate
met
ho
ds
• To
war
ds p
redi
ctab
le s
ched
ulin
g
• M
oti
vati
on
& T
erm
s
• C
ateg
ori
es &
Exa
mp
les
455
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
455
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Pred
icta
ble
sche
dulin
g
Tem
po
ral s
cop
es
Co
mm
on
att
rib
ute
s:
• M
inim
al &
max
imal
de
lay
afte
r cr
eati
on
• M
axim
al e
laps
ed t
ime
• M
axim
al e
xecu
tion
tim
e
• A
bso
lute
dea
dlin
eTa
sk i
t1
0352
025
10
dea
dlin
e
min
. del
aym
ax. d
elay
acti
vate
d susp
end
edre-a
ctiv
ated
term
inat
ed
crea
ted
elap
se ti
me
max
. ela
pse
tim
em
ax. e
xec.
tim
e
456
Sch
edu
ling
© 2
019
Uw
e R
. Zim
mer
, The
Aus
tral
ian
Nat
iona
l Uni
vers
ity
page
456
of 7
57 (c
hapt
er 6
: “Sc
hedu
ling”
up
to p
age
458)
Pred
icta
ble
sche
dulin
g
Tem
po
ral s
cop
es
Co
mm
on
att
rib
ute
s:
• M
inim
al &
max
imal
de
lay
afte
r cr
eati
on
• M
axim
al e
laps
ed t
ime
• M
axim
al e
xecu
tion
tim
e
• A
bso
lute
dea
dlin
eTa
sk i
t1
0352
025
10
dea
dlin
e
exec
uti
on
tim
e
min
. del
aym
ax. d
elay
acti
vate
d susp
end
edre-a
ctiv
ated
term
inat
ed
crea
ted
elap
se ti
me
max
. ela
pse
tim
em
ax. e
xec.
tim
e