Distributed Software Transactional Memories - Distributed Systems ...

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Basic Concepts ! It is hard or impossible to structure a program in a set of parallel independent tasks. ! We need efficient and simple mechanisms to manage concurrency. M. Couceiro, P. Romano, L. Rodrigues, HPCS 2011
Explicit synchronization ! One of the most fundamental and simple synchronization primitive is the lock non-synchronized code; lock (); do stuff on shared data; unlock (); more non-synchronized code; M. Couceiro, P. Romano, L. Rodrigues, HPCS 2011
Page 1 and 2: Distributed Software Transactional
Page 3 and 4: Contents ! Part I: (Non-Distributed
Page 5 and 6: Basic Concepts ! Concurrent program
Page 7 and 8: Basic Concepts ! Ideally ! Performa
Page 9: Basic Concepts ! Ideally ! Performa
Page 13 and 14: Fine Grained Parallelism? ! Very co
Page 15 and 16: Abstractions for simplifying concur
Page 17 and 18: Transactional Memories ! Hide away
Page 19 and 20: TMs: where we are, challenges, tren
Page 21 and 22: Run-time ! How does it work? ! The
Page 23 and 24: Example of optimistic concurrency c
Page 25 and 26: Many, many, variants exist ! For in
Page 27 and 28: How to choose? ! What is a correct
Page 29 and 30: Theoretical Foundations ! Safety: !
Page 31 and 32: Histories ! The execution of a set
Page 33 and 34: Histories ! Two transactions are se
Page 35 and 36: Histories ! A history is sequential
Page 37 and 38: Histories ! A history is sequential
Page 39 and 40: Histories ! Two histories are equiv
Page 41 and 42: What the programmer wants? ! Progra
Page 43 and 44: Serializability ! Serializable? WO1
Page 45 and 46: Serializability ! Serializable? WO1
Page 47 and 48: Opacity ! Serializable (blue aborts
Page 49 and 50: Opacity ! In a database environment
Page 51 and 52: Opacity: example Initially: x:=1; y
Page 57 and 58: ! Intuitive definition: Opacity [GK
Page 59 and 60: Does classic optimistic concurrency
Page 61 and 62:
Progress ! STMs can abort transacti
Page 63 and 64:
Conditional progress: obstruction f
Page 65 and 66:
Contention-managers Let TA be execu
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CM: Backoff Let TA be executing and
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CM: Greedy Let TA be executing and
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(Non-Distributed) STMs ! Basic Conc
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DSTM ! Killer write: ! Ownership. !
Page 75 and 76:
DSTM - Reads and Validation ! Concu
Page 77 and 78:
DSTM - Why is careful read needed?
Page 79 and 80:
JVSTM ! Java Versioned Software Tra
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JVSTM - Versioned boxes B body: ! V
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JVSTM - Algorithm ! Upon write, jus
Page 85 and 86:
Contents ! Part I: (Non-Distributed
Page 87 and 88:
Origins ! Convergence of two main a
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DSTMs vs DSM ! DSTMs are simpler to
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DSTMs vs DBMS ! Transactions are of
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Goals ! Better performance: ! Doing
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Distribution Strategies ! Single Sy
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Distributed STMs ! Origins ! Goals
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Control Flow Model ! Data is static
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Toolbox ! Atomic Commitment ! Unifo
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2-phase commit coordinator particip
Page 105 and 106:
3PC coordinator participant partici
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Uniform Reliable Broadcast ! Allows
Page 109 and 110:
Atomic Broadcast ! Reliable broadca
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Abcast with optimistic delivery ! T
Page 113 and 114:
ABcast with optimistic delivery fin
Page 115 and 116:
Replicating a single lock ! In abse
Page 117 and 118:
Replicating a single lock T1 lock()
Page 119 and 120:
Single-phase schemes ! State machin
Page 121 and 122:
State-machine replication AB of T1
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Primary-backup ! Write transactions
Page 125 and 126:
Page 127 and 128:
Multi-master ! Two transactions may
Page 129 and 130:
Non-voting ! The transaction execut
Page 131 and 132:
Page 133 and 134:
Voting R1 Execution Transaction T1
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Part III: Case-Studies ! Partitione
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Cluster-STM ! Software Transactiona
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Cluster-STM (a) increment ( proc t
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Cluster-STM increment local ( proc
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Cluster-STM ! Read locks (RL) vs. r
Page 145 and 146:
Cluster-STM ! Write buffering: two
Page 147 and 148:
Cluster-STM: Graph Analysis (SSCA2)
Page 149 and 150:
Sinfonia ! Sinfonia: A new paradigm
Page 151 and 152:
SA † VMware, Palo Alto, CA, USA S
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... Min API write items mem-id mem-
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30 if action then apply writems 31
Page 157 and 158:
Page 159 and 160:
D 2 STM ! Non-voting replication sc
Page 161 and 162:
D 2 STM AB of both T1’s readset &
Page 163 and 164:
D 2 STM M. Couceiro, P. Romano, L.
Page 165 and 166:
D 2 STM ! False Positives: ! An ite
Page 167 and 168:
D 2 STM ! Write transaction T: ! Lo
Page 169 and 170:
D 2 STM ! STMBench7: Results M. Cou
Page 171 and 172:
ALC ! Asynchronous Lease Certificat
Page 173 and 174:
ALC ! Transactions are locally proc
Page 175 and 176:
ALC P1 Lease Request (AB) Lease Ens
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ALC P1 Lease Request Lease Ensured
Page 179 and 180:
ALC P1 Lease Request Apply Lease En
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ALC Application Distributed STM API
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ALC ! Synthetic “Worst case” sc
Page 185 and 186:
Page 187 and 188:
Basic Active Replication Atomic Bro
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Improvement Atomic Broadcast Tx Exe
Page 191 and 192:
Speculative Opt Atomic Broadcast Tx
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AGGRO Algorithm upon opt-Deliver(Ti
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AGGRO Algorithm upon read(Ti, X) if
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AGGRO Algorithm upon abort(Ti) abor
Page 199 and 200:
Contents ! Part I: (Non-Distributed
Page 201 and 202:
Conclusions ! No technique outperfo
Page 203 and 204:
CLOUD-TM ! DTMs: a programming para
Page 205 and 206:
Euro-TM Cost Action ! Research netw
Page 207 and 208:
Bibliography ! [BAC08] Robert L. Bo
Page 209 and 210:
Bibliography ! [GHP05] Rachid Guerr
Page 211 and 212:
Bibliography ! [KAJLKW08] Christos
Page 213:
The End Thank you. M. Couceiro, P.
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