1. RingSTM
Presented by: Amr Abed

2. About the paper
Title
“RingSTM: Scalable Transactions with a Single Atomic
Instruction”
Authors
Michael F. Spear, Maged M. Michael, and Christoph von Praun
Published in
The 20th annual symposium on Parallelism in algorithms and
architectures (SPAA)
Year
2008

3. Outline
Motivation
System Overview
How it works
Evaluation

4. Outline
Motivation
System Overview
How it works
Evaluation

5. Motivation
Orec-based STM
Location-based metadata
TX writing to W locations
O(W) CAS operations
Committing R/W TX
O(R+W) overhead
All validation done in CS
Ring STM
TX-based metadata
TX writing to W locations
No CAS operations
Committing R/W TX
Single CAS operation
Bloom filters used for validation

6. Outline
Motivation
System Overview
How it works
Evaluation

7. Transaction
Start
Timestamp
Write
Buffer
Write Filter
Read Filter

8. The Ring
39
40
46
41
42
Writing
45
44
43
Complete

9. Ring Entry
Commit
Timestamp
Status
Write Filter

10. Bloom Filter
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

11. Bloom Filter
Inserting A
A
Hash Functions
13
10
7
1
0
0
1
0
0
0
1
0
0
0
1
0
0
0
0
0
0
1
0
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

12. Bloom Filter
Inserting B
B
Hash Functions
12
9
7
2
0
0
1
0
1
0
1
0
1
0
1
0
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

13. Bloom Filter
Searching for A
A
Hash Functions
13
10
7
1
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

14. Bloom Filter
Searching for C
C
Hash Functions
12
10
3
7
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

15. Bloom Filter
Searching for D
D
Hash Functions
12
10
2
7
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

16. Outline
Motivation
System Overview
How it works
Evaluation

17. New Transaction
39
40
41
Start Time
43 42
46
Write
Buffer
Write Filter
Read Filter
45
44
43
Writing
Complete

18. On Write
Add address to Write set
Address
Hash Functions
12
10
1
7
Write filter
0
0
1
0
1
0
1
0
0
1
0
0
0
0
1
0
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

19. On Write
Add <address, value> to Write buffer
Address
Value
Address
Hash Functions
12
10
Write
Buffer
1
7
Write filter
0
0
1
0
1
0
1
0
0
1
0
0
0
0
1
0
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

20. On Read
Address is in Write set
Address
Hash Functions
13
10
7
1
Write filter
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

21. On Read
Get value from write buffer
Address
Address
Hash Functions
13
10
Write
Buffer
7
1
Value
Write filter
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

22. On Read
Address is not in Write Set
Address
Hash Functions
12
10
3
7
Write filter
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

23. On Read
Get value from memory
Address
Address
Hash Functions
12
10
Memory
3
7
Value
Write filter
0
0
1
1
0
1
1
0
1
0
0
0
0
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

24. On Read
Add address to read set
Address
Hash Functions
12
10
3
7
Read filter
0
0
1
0
1
0
1
1
0
1
0
0
0
0
1
1
1
0
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0

25. On Read
Check for conflicts
39
40
46
41
42
Start Time
44
43
Write
Buffer
Write Filter
Read Filter
45
44
43

26. On Commit
Add new entry, and update index
47
39
40
46
41
42
Start Time
43
Write
Buffer
Write Filter
Read Filter
45
44
43

27. On Commit
Check for conflicting writers
47
40
46
41
42
Start Time
43
Write
Buffer
Write Filter
Read Filter
45
44
43

28. On Commit
If no conflicts, write to memory
Address
Address
Write
Buffer
Memory

29. On Commit
Set status to complete
47
40
46
45
41
42
44
43

30. Outline
Motivation
System Overview
How it works
Evaluation

31. Results

32. Results

33. Results

34. Summary
Use of Bloom filter accelerates validation
Single RMW operation to commit
Trade-off between size of Bloom filter and false
conflicts
Ring size is a bottleneck for large number of threads

35. Thank you