(T'-B

^

pneMoty

Jlik

^

'I^P-}

s-=:^^e<]TLB#iRtPiui£MM5i^^^i

«

m

t^jl^reference

bitlx^l

°

•

dirty

bittil^MiS^l

°

»a^jib

•

spiSTLB$^i^R:^ii}^Km^i^

°

jasti^RiiaR

wMrnAmmmmiJiB

•

•

sB)STLB^i^it^K]i0<]RMitii"

itmmimMmi&m'Awmm

-

"fL-C.!

(Ano'ic^^

vt.

tvisr

yo.-ii

-

'ifl^tf^Ction

TH?

'i-

i"^

Ip

•

'

dalo^

TLB

&

rH

fx

rfa^e.

Consider

a

memory

system

with

the

following

parameters:

•

Translation

Lookaside

li

u^fer

has

512

entries

and

is

2-way

set

associative.

•

64Kbyte

LI

Data

Cache

has

128

byte

lines

and

is

also

2-way

set

associative.

•

Virtual

addresses

are

64-bits

and

physical

addresses

are

32

bits.

8KB

page

size.

72

I

Below

are

diagrams

of

the

cache

and

TLB.

What

is

the

number

of

bits

in

the

diagrams

labeled

A,

B,

C,...

^

^

n

T

Physical

address

Tag/status

Data

Tag/status

Data

■ )

E

D

T

I

©

Cache

F

I

G

H

Vi

Virtual

address

Tag/status

Data

Tag/status

Data

I

;r

TLB

Answer

A

B

C

D

E

\\

F

G

H

I

17 8

7

1024

18

42

9

13

19

1-3^-13^

(1-

The

following

table

is

a

stream

of

virtual

addresses.

Assume/4

KB^ages,

a

four-entry

fully

associative

TLB,

and

true

LRU

replacement.

If

pages

must

be

brought

in

from

disk,

increment

the

next

largest

page

number.

4095,

31272,15789,15000,

7193,4096,

8912

TLB

Valid

Physical

Page

Number

1

11

12

1

7

4

1

3

6

0

4

9

Page

table

I

X

J

V

t

L

0

(f

Valid

Phi^icaLpageorinij^k

1

5

0

Disk

0

Disk

1

6

1

9

1

11

0

Disk

1

4

0

Disk

0

Disk

1

3

1

12

Given

the

address

stream

above,

and

the

shown

initial

state

of

the

TLB

and

page

table,

show

the

final

state

of

the

system.

Also

list

for

each

reference

if

it

is

a

hit

in

the

TLB,

a

hit

in

the

page

table,

or

a

page

fault.

Answer:

(H:

Hit

in

TLB,

M:

Miss

in

TLB

hit

in

page

table,

PF:

Page

Fault)

VA

4095

31272

15789

15000

7193

4096

8912

VPN

0

7

3

3

1

1

2

H/M/PF

M

H

H

H

PF

H

PF

TLB

Valid

Tag

Physical

Page

Number

1

1

13

1

7

4

1

3

6

1

2

14

74

I

mArn

Page

table

Valid

Physical

page

or

in

disk

1

5

1

13

1

14

1

6

1

9

1

11

0

Disk

1

4

0

Disk

0

Disk

1

3

1

12

«

^

TLB

^

TMi^^B^TCPU

^

^

TLB

~

Cache

^>

f'

.

/

Hard

Disk

Virtual

C

Physical

Memory

Virtual

Page

no.

Physical

Physical

V

r

d

page

no.

Virtual

V

r

d

tag

page

i

TLB

U0.

Disk

address

1

1

0

1

3

Disk

address

2

1

1

Disk

address

3

Disk

address

4

1

2

Page

Table

0

12

3

I

tag

I

index

[

offset

|

Physical

address

1

0

1

.3

1

1

1

2

1

100

Tag

I

Index

I

100

r

I

Page

offeet

Vi

rtual

Page

no.

J

PU

Virtual

address