RingSTMPresented by: Amr Abed

Title“RingSTM: Scalable Transactions with a Single Atomic Instruction”

AuthorsMichael F. Spear, Maged M. Michael, and Christoph von Praun

Published inThe 20th annual symposium on Parallelism in algorithms and architectures (SPAA)

Year2008

About the paper

MotivationSystem OverviewHow it worksEvaluation

Outline

MotivationSystem OverviewHow it worksEvaluation

Outline

Motivation

Orec-based STMLocation-based metadataTX writing to W locations

O(W) CAS operationsCommitting R/W TX

O(R+W) overhead All validation done in CS

Ring STMTX-based metadataTX writing to W locations

No CAS operationsCommitting R/W TX

Single CAS operationBloom filters used for validation

MotivationSystem OverviewHow it worksEvaluation

Outline

Transaction

Write Buffer

StartTimestamp

Write FilterRead Filter

The Ring

41

42

43

40

44

46

39

45

WritingComplete

index

Ring Entry

CommitTimestamp

Write Filter

Status

0 0 0 0 0 0 0 0 0 0 0 0 0 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Bloom Filter

1 0 0 1 0 0 1 0 0 0 0 0 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

0 0 0 0 0 0 0 0 0 0 0 0 0 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Bloom Filter

Hash Functions

A

171013

Inserting A

1 0 0 1 0 0 1 0 0 0 0 0 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Bloom Filter

Hash Functions

B

27912

Inserting B

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Bloom Filter

Hash Functions

A

171013

Searching for A

Positive

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Bloom Filter

Hash Functions

C

371012

Searching for C

Negativ

e

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Bloom Filter

Hash Functions

D

271012

Searching for D

False Positive

MotivationSystem OverviewHow it worksEvaluation

Outline

Start

index

New Transaction

41

42

43

40

44

46

39

45 WritingComplete

Write Buffer

Start Time43

Write FilterRead Filter

1 0 0 1 0 0 1 0 0 0 0 0 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 0 0 1 0 0 0 1 0 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

On Write

Hash Functions

Address

171012

Write filter

Add address to Write set

1 0 0 1 0 0 1 0 0 0 0 0 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 0 0 1 0 0 0 1 0 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

On Write

Hash Functions

Address

171012

Write filter

Write Buffer

Value

Address

Add <address, value> to Write buffer

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

On Read

Hash Functions

Address

171013

Address is in Write set

Write filter

On Read

Get value from write buffer

Write Buffer

Value

Address

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Hash Functions

Address

171013

Write filter

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

On Read

Hash Functions

Address

371012

Address is not in Write Set

Write filter

On Read

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 1 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

Hash Functions

Address

371012

Get value from memory

Write filter

Memory

Value

Address

1 1 0 1 1 0 1 0 0 0 1 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

1 0 0 1 1 0 1 0 0 0 0 1 1 00015 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

On Read

Hash Functions

Address

371012

Add address to read set

Read filter

Write Buffer

Start Time43

Write FilterRead Filter

index

On Read

41

42

43

40

44

46

39

45Read Filter

Start Time44

Check for conflicts

Write Buffer

Start Time43

Write FilterRead Filter

index

On Commit

41

42

43

40

44

46

39

45

47

Add new entry, and update index

Write Buffer

Start Time43

Write FilterRead Filter

index

On Commit

41

42

43

40

44

46

47

45

Write Filter

Check for conflicting writers

On Commit

Memory

Address

WriteBuffer

Address

If no conflicts, write to memory

index

On Commit

41

42

43

40

44

46

47

45 4445

46

47

Set status to complete

MotivationSystem OverviewHow it worksEvaluation

Outline

Results

Results

Results

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

Summary

Thank you