Colorama: Ar chitectural Support for Data-Centric Synchr onization · 2007. 9. 14. · Luis Ceze Colorama February 2007 NYV\W Colorama: Ar chitectur e Support for DCS ¥ Main advantage:
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Colorama: Architectural Support for
Data-Centric Synchronization
Luis Ceze, Pablo Montesinos,
Christoph von Praun! and Josep Torrellas
HPCA, February 2007
http://iacoma.cs.uiuc.edu
University of Illinois at Urbana-Champaign!IBM Research
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
2
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
•Thread synchronization is very challenging
2
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
•Thread synchronization is very challenging
•Lock-based synchronization:
• coarse-grain: low performance; fine-grain: error-prone
2
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
•Thread synchronization is very challenging
•Lock-based synchronization:
• coarse-grain: low performance; fine-grain: error-prone
•Transactional Memory-based synchronization:
• programmability ~ coarse-grain locking; performance ~ fine-grain locking
2
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
•Thread synchronization is very challenging
•Lock-based synchronization:
• coarse-grain: low performance; fine-grain: error-prone
•Transactional Memory-based synchronization:
• programmability ~ coarse-grain locking; performance ~ fine-grain locking
•Locks and TM shortcoming:
• programmer needs to annotate code around every potential access to
shared data
2
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
•Thread synchronization is very challenging
•Lock-based synchronization:
• coarse-grain: low performance; fine-grain: error-prone
•Transactional Memory-based synchronization:
• programmability ~ coarse-grain locking; performance ~ fine-grain locking
•Locks and TM shortcoming:
• programmer needs to annotate code around every potential access to
shared data
2
Need to make parallel programming much simpler:
Luis Ceze Colorama February 2007
Challenge: Simplify Parallel Programming
•Thread synchronization is very challenging
•Lock-based synchronization:
• coarse-grain: low performance; fine-grain: error-prone
•Transactional Memory-based synchronization:
• programmability ~ coarse-grain locking; performance ~ fine-grain locking
•Locks and TM shortcoming:
• programmer needs to annotate code around every potential access to
shared data
2
Need to make parallel programming much simpler:
"Data-Centric Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
declare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
A B Cdeclare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
A B Cdeclare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
A B Cdeclare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C declare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C declare A,B,C
Colorama: Data-Centric
Synchronization (DCS)
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C declare A,B,C
color red A,B
Colorama: Data-Centric
Synchronization (DCS)
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C declare A,B,C
color red A,B
Colorama: Data-Centric
Synchronization (DCS)
color blue C
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
A B Cdeclare A,B,C declare A,B,C
color red A,B
Colorama: Data-Centric
Synchronization (DCS)
color blue C
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
ld A
st A
st B
A B Cdeclare A,B,C declare A,B,C
color red A,B
Colorama: Data-Centric
Synchronization (DCS)
color blue C
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
ld A
st A
st B
ld C
st C
A B Cdeclare A,B,C declare A,B,C
color red A,B
Colorama: Data-Centric
Synchronization (DCS)
color blue C
A B C
Luis Ceze Colorama February 2007
Conventional: Code-Centric
Synchronization (CCS)
3
lock L1ld A
st A
st B
unlock L1
lock L2ld C
st C
unlock L2
ld A
st A
st B
ld C
st C
System infers and
enforces critical sections
A B Cdeclare A,B,C declare A,B,C
color red A,B
Colorama: Data-Centric
Synchronization (DCS)
color blue C
Luis Ceze Colorama February 2007
DCS Reduces Programmer Effort
4
Luis Ceze Colorama February 2007
DCS Reduces Programmer Effort
4
code-centric data-centric
Luis Ceze Colorama February 2007
DCS Reduces Programmer Effort
4
code-centric data-centric
reasoning non-local local
Luis Ceze Colorama February 2007
DCS Reduces Programmer Effort
4
code-centric data-centric
reasoning non-local local
critical
sectionsexplicitly
defined
inferred by
system
Luis Ceze Colorama February 2007
DCS Reduces Programmer Effort
4
code-centric data-centric
reasoning non-local local
critical
sectionsexplicitly
defined
inferred by
system
"Intuition: Local reasoning improves programmer
productivity by reducing chances of mistakes
Luis Ceze Colorama February 2007
Example from mysql
5
Luis Ceze Colorama February 2007
Example from mysql
5
header
info
• all header protected by global lock
• global lock used in 29 sites
Luis Ceze Colorama February 2007
Example from mysql
5
header
info
• all header protected by global lock
• global lock used in 29 sites
•info protected by per-record lock
• per-record lock used in 14 sites
Luis Ceze Colorama February 2007
Example from mysql
5
header
info
CCS
• all header protected by global lock
• global lock used in 29 sites
•info protected by per-record lock
• per-record lock used in 14 sites
Luis Ceze Colorama February 2007
Example from mysql
5
header
info
CCS
• all header protected by global lock
• global lock used in 29 sites
•info protected by per-record lock
• per-record lock used in 14 sites
•header fields same color
• each info different color
DCS
Luis Ceze Colorama February 2007
Example from mysql
5
header
info
Luis Ceze Colorama February 2007
Software DCS
6
Luis Ceze Colorama February 2007
Software DCS
•Software-only DCS concurrently developed [Vaziri PoPL’06]
• for object-oriented languages (Java)
6
Luis Ceze Colorama February 2007
Software DCS
•Software-only DCS concurrently developed [Vaziri PoPL’06]
• for object-oriented languages (Java)
•Needs whole-program analysis
6
Luis Ceze Colorama February 2007
Software DCS
•Software-only DCS concurrently developed [Vaziri PoPL’06]
• for object-oriented languages (Java)
•Needs whole-program analysis
•Impractical in C/C++
• Pointer aliasing
• Compiler often does not have access to whole code
6
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
• Interface to assign colors to shared data (memory tagging)
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
• Interface to assign colors to shared data (memory tagging)
•Exit critical section using an Exit Policy
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
• Interface to assign colors to shared data (memory tagging)
•Exit critical section using an Exit Policy
• HW provides flexible primitives to exit critical sections
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
• Interface to assign colors to shared data (memory tagging)
•Exit critical section using an Exit Policy
• HW provides flexible primitives to exit critical sections
• Compiler inserts the code that implements the policy
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
• Interface to assign colors to shared data (memory tagging)
•Exit critical section using an Exit Policy
• HW provides flexible primitives to exit critical sections
• Compiler inserts the code that implements the policy
• Programmer must know (and follow) the Exit Policy
7
Luis Ceze Colorama February 2007
Colorama: Architecture Support for DCS
•Main advantage: HW can cheaply watch all memory refs
•Enter critical section when colored data is touched
• HW checks the color of every memory access
• Interface to assign colors to shared data (memory tagging)
•Exit critical section using an Exit Policy
• HW provides flexible primitives to exit critical sections
• Compiler inserts the code that implements the policy
• Programmer must know (and follow) the Exit Policy
•Structures to keep track of color ownership
7
Luis Ceze Colorama February 2007
Architecture Components
8
Start
Address
End
Address ColorID
Palette
Shared
Luis Ceze Colorama February 2007
Architecture Components
8
Start
Address
End
Address ColorID
Palette
Shared Per Thread
Owned Colors Array
Color Acquire Bitmap
Register (CAB)
Color Release Bitmap
Register (CRB)
Thread Color Status
ColorIDi
Luis Ceze Colorama February 2007
Architecture Components
8
Luis Ceze Colorama February 2007
Colorama Operation Example
9
Palette
Owned Colors
Array
Luis Ceze Colorama February 2007
Colorama Operation Example
9
color A red
color B red
color C red
color E blue
color F blue
Palette
Owned Colors
Array
Luis Ceze Colorama February 2007
Colorama Operation Example
9
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
Owned Colors
Array
Luis Ceze Colorama February 2007
Colorama Operation Example
9
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
Owned Colors
Array
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
Owned Colors
Array
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
Owned Colors
Array
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
Owned Colors
Array
red
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
Owned Colors
Array
red
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
Owned Colors
Array
red
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
red
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
st E
st F
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
blue
!trap to user-level handler, start blue critical section
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
st E
st F
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
blue
!trap to user-level handler, start blue critical section
!trap to user-level handler, exit blue critical section
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
st E
st F
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
!trap to user-level handler, start blue critical section
!trap to user-level handler, exit blue critical section
thread 1
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
st E
st F
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
!trap to user-level handler, start blue critical section
!trap to user-level handler, exit blue critical section
thread 1
inferred critical
sections
Luis Ceze Colorama February 2007
Colorama Operation Example
9
ld A
st B
st C
st E
st F
color A red
color B red
color C red
color E blue
color F blue
Palette
A red
B red
C red
E blue
F blue
!trap to user-level handler, start red critical section
!trap to user-level handler, exit red critical section
Owned Colors
Array
!trap to user-level handler, start blue critical section
!trap to user-level handler, exit blue critical section
thread 1
inferred critical
sections
Underlying synchronization substrate:
TM or locks. Focusing on TM.
Luis Ceze Colorama February 2007
Exiting a Critical Section
10
Luis Ceze Colorama February 2007
Exiting a Critical Section
•Knowing when to end a critical section is difficult
10
Luis Ceze Colorama February 2007
Exiting a Critical Section
•Knowing when to end a critical section is difficult
•Optimal place undecidable
10
Luis Ceze Colorama February 2007
Exiting a Critical Section
•Knowing when to end a critical section is difficult
•Optimal place undecidable
•Solution is to rely on an agreed Exit Policy
• Exit Policy becomes part of the programming model
10
Luis Ceze Colorama February 2007
Exiting a Critical Section
•Knowing when to end a critical section is difficult
•Optimal place undecidable
•Solution is to rely on an agreed Exit Policy
• Exit Policy becomes part of the programming model
•We use:
• Return of subroutine where the critical section started [Vaziri’06, Wang’06]
10
Luis Ceze Colorama February 2007
Exit Policy
11
Luis Ceze Colorama February 2007
Exit Policy
11
void foo1()
{
...
...
A = ...
...
...
...
}
ColorIDA
critical
section
Luis Ceze Colorama February 2007
Exit Policy
11
void foo1()
{
...
...
A = ...
...
...
...
}
ColorIDA
critical
section
void foo1()
{
...
...
A = ...
...
...
B = ...
...
...
}
ColorIDA
critical
sectionColorID
B
critical
section
Luis Ceze Colorama February 2007
Exit Policy
11
void foo1()
{
...
...
A = ...
...
...
...
}
ColorIDA
critical
section
void foo1()
{
...
A = ...
foo2();
...
}
void foo2()
{
...
B = ...
...
}
ColorIDA
critical
section
ColorIDB
critical
section
void foo1()
{
...
...
A = ...
...
...
B = ...
...
...
}
ColorIDA
critical
sectionColorID
B
critical
section
Start
Address
End
Address ColorID
Palette
Shared Per Thread
Owned Colors Array
Color Acquire Bitmap
Register (CAB)
Color Release Bitmap
Register (CRB)
Thread Color Status
ColorIDi
Luis Ceze Colorama February 2007
Architecture Components
12
Luis Ceze Colorama February 2007
Detailed Operation
13
f()Color Acquire Bitmap
(CAB register)Owned Colors
Array
Luis Ceze Colorama February 2007
Detailed Operation
13
f()Color Acquire Bitmap
(CAB register)
ld Z
Owned Colors
Array
Luis Ceze Colorama February 2007
Detailed Operation
13
f()Color Acquire Bitmap
(CAB register)
1ld Z
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
Color Acquire Bitmap
(CAB register)
1ld Z
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
Color Acquire Bitmap
(CAB register)
1ld Z
stack " CAB
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
Color Acquire Bitmap
(CAB register)
1ld Z
stack " CAB
CAB " 0
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
Color Acquire Bitmap
(CAB register)
ld Z
stack " CAB
CAB " 0
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
Color Acquire Bitmap
(CAB register)
ld Z
stack " CAB
CAB " 0...
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
Color Acquire Bitmap
(CAB register)
ld Z
stack " CAB
CAB " 0...
Owned Colors
Array
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
ld Z
stack " CAB
CAB " 0...
Owned Colors
Array
Blue
Red
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
ld Z
stack " CAB
CAB " 0...
Owned Colors
Array
ld T
Blue
Red
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
ld B
ld Z
stack " CAB
CAB " 0...
Owned Colors
Array
ld T
Blue
Red
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
1
ld B
ld Z
stack " CAB
CAB " 0...
Owned Colors
Array
ld T
Blue
Red
Green
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
1
ld B
ld Z
stack " CAB
CAB " 0
...
...
Owned Colors
Array
ld T
Blue
Red
Green
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
1
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB
...
...
Owned Colors
Array
ld T
Blue
Red
Green
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
1
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB ! exits critical sections Red and Green
...
...
Owned Colors
Array
ld T
Blue
Red
Green
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
1
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB ! exits critical sections Red and Green
...
...
Owned Colors
Array
ld T
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
1
Color Acquire Bitmap
(CAB register)
1
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB
CAB " stack
! exits critical sections Red and Green
...
...
Owned Colors
Array
ld T
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
Color Acquire Bitmap
(CAB register)
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB
CAB " stack
! exits critical sections Red and Green
1
...
...
Owned Colors
Array
ld T
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
Color Acquire Bitmap
(CAB register)
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB
CAB " stack
! exits critical sections Red and Green
...
ret
1
...
...
Owned Colors
Array
ld T
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
Color Acquire Bitmap
(CAB register)
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB
CAB " stack
! exits critical sections Red and Green
...
ret
1
...
...
subroutine prologue/epilogue
inserted by the compiler
Owned Colors
Array
ld T
Blue
Luis Ceze Colorama February 2007
Detailed Operation
13
f()
call g()
ld A
Color Acquire Bitmap
(CAB register)
ld B
ld Z
stack " CAB
CAB " 0
CRB " CAB
CAB " stack
! exits critical sections Red and Green
...
ret
1
...
...
subroutine prologue/epilogue
inserted by the compiler
Owned Colors
Array
ld T
Blue
Hardware is generic: exit policy
configurable and specified by SW.
Protection
Lookaside
Buffer (PLB)
Processor
Multilevel
Permissions
Table
Memory
MMP with the Palette extensions
Luis Ceze Colorama February 2007
Palette Implementation
14
Mondrian Memory Protection [Witchel ASPLOS’02]
Luis Ceze Colorama February 2007
Why Multiple Colors?
15
Luis Ceze Colorama February 2007
Why Multiple Colors?
•Intuitive way of nesting inferred transactions
15
Luis Ceze Colorama February 2007
Why Multiple Colors?
•Intuitive way of nesting inferred transactions
•Conveys more information on how shared data is used
15
Luis Ceze Colorama February 2007
Why Multiple Colors?
•Intuitive way of nesting inferred transactions
•Conveys more information on how shared data is used
• Allows future exit policy refinement
15
Luis Ceze Colorama February 2007
Why Multiple Colors?
•Intuitive way of nesting inferred transactions
•Conveys more information on how shared data is used
• Allows future exit policy refinement
• More opportunity for optimizations
15
Luis Ceze Colorama February 2007
Why Multiple Colors?
•Intuitive way of nesting inferred transactions
•Conveys more information on how shared data is used
• Allows future exit policy refinement
• More opportunity for optimizations
• e.g., assume transactions of different colors do not collide
15
Luis Ceze Colorama February 2007
Why Multiple Colors?
•Intuitive way of nesting inferred transactions
•Conveys more information on how shared data is used
• Allows future exit policy refinement
• More opportunity for optimizations
• e.g., assume transactions of different colors do not collide
•Lock-based implementation: each color maps to a lock
15
Luis Ceze Colorama February 2007
Using Colorama to Debug Conventional Code
16
Luis Ceze Colorama February 2007
Using Colorama to Debug Conventional Code
•Programmer uses explicit transactions AND colors data
16
Luis Ceze Colorama February 2007
Using Colorama to Debug Conventional Code
•Programmer uses explicit transactions AND colors data
•The system can monitor:
16
Luis Ceze Colorama February 2007
Using Colorama to Debug Conventional Code
•Programmer uses explicit transactions AND colors data
•The system can monitor:
" colored data should only be accessed inside transactions
16
Luis Ceze Colorama February 2007
Using Colorama to Debug Conventional Code
•Programmer uses explicit transactions AND colors data
•The system can monitor:
" colored data should only be accessed inside transactions
" transactions of different colors should not collide
16
Luis Ceze Colorama February 2007
Using Colorama to Debug Conventional Code
•Programmer uses explicit transactions AND colors data
•The system can monitor:
" colored data should only be accessed inside transactions
" transactions of different colors should not collide
" transactions should typically access a single color
- if multiple colors are accessed, nesting could be recommended
16
Luis Ceze Colorama February 2007
Evaluation
17
Luis Ceze Colorama February 2007
Evaluation
•No large Colorama programs (yet)
17
Luis Ceze Colorama February 2007
Evaluation
•No large Colorama programs (yet)
•Evaluation consists in detailed profiling of open-source
parallel programs
• Developed Pin tool to profile critical sections and memory allocation
• Used MySQL, FireFox, aolserver, tuxracer, ...
17
Luis Ceze Colorama February 2007
Evaluation
•No large Colorama programs (yet)
•Evaluation consists in detailed profiling of open-source
parallel programs
• Developed Pin tool to profile critical sections and memory allocation
• Used MySQL, FireFox, aolserver, tuxracer, ...
•Estimated Exit Policy suitability
• Majority of critical sections entry/exit are inside same subroutine
17
Luis Ceze Colorama February 2007
Evaluation
•No large Colorama programs (yet)
•Evaluation consists in detailed profiling of open-source
parallel programs
• Developed Pin tool to profile critical sections and memory allocation
• Used MySQL, FireFox, aolserver, tuxracer, ...
•Estimated Exit Policy suitability
• Majority of critical sections entry/exit are inside same subroutine
•Estimated overheads
• Palette increases memory footprint by about 2.5%
17
Luis Ceze Colorama February 2007
Also in the paper...
•More examples
•Detailed API
•Lock-based implementation issues
•Code compatibility issues
• conditional wait, linking with non-Colorama code, ...
•Debugging Colorama code
•Additional characterization
18
Luis Ceze Colorama February 2007
Conclusion
19
Luis Ceze Colorama February 2007
Conclusion
•We presented a feasible implementation of DCS
19
Luis Ceze Colorama February 2007
Conclusion
•We presented a feasible implementation of DCS
•DCS can greatly simplify parallel programming
• programmer only specifies the colors and follows a simple policy
• the system, in return, guarantees consistency of shared data
19
Luis Ceze Colorama February 2007
Conclusion
•We presented a feasible implementation of DCS
•DCS can greatly simplify parallel programming
• programmer only specifies the colors and follows a simple policy
• the system, in return, guarantees consistency of shared data
•Current work:
• Other exit policies under investigation
• Deeper evaluation
19
Colorama: Architectural Support for
Data-Centric Synchronization
Luis Ceze, Pablo Montesinos,
Christoph von Praun! and Josep Torrellas
HPCA, February 2007
http://iacoma.cs.uiuc.edu
University of Illinois at Urbana-Champaign!IBM Research
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