{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/23890"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/23890","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"On Partial Aborts and Reducing Validation Costs in Fault-tolerant Distributed Transactional Memory","abstract":"Distributed Transactional Memory (DTM) is an emerging synchronization abstraction thatpromises to alleviate the scalability, programmability, and composability challenges of lock-based distributed synchronization. With DTM, programmers organize code that read/writeshared memory objects, both local and remote, as memory transactions. An underlying DTMframework guarantees atomicity, isolation, and consistency properties for those transactionsthrough speculative concurrency control. In DTM, restarting an aborted transaction from the beginning can degrade performance astransactional conflicts may have occurred in the later part of the transaction, wasting work.The partial abort method alleviates this difficulty by enabling a transaction to be rolled backto the point where objects in the transaction's read-set and write-set are still consistent.In this thesis, we present protocols for supporting partial aborts in QR-DTM, a fault-tolerant DTM that uses quorum protocols for distributed concurrency control in the presence offailures. We focus on two partial abort models: closed nesting, which allows transactions to be nested and inner transactions to be rolled back without rolling back outer transactions;and checkpointing, which allows the transaction state to be saved in checkpoints throughout execution and transactions to be rolled back to those checkpoints. We present protocols that support these partial abort models in QR-DTM, called QR-CN and QR-CHK. We implemented these protocols and conducted experimental studies using macro-benchmarks(e.g., distributed versions of STAMP benchmark), and micro-benchmarks (e.g., distributed data structures). Our studies reveal that QR-CN improves throughput by as much as 101% over flat nesting in specific cases, with an average improvement of 53%. We also develop QR-ACN, a framework that automatically decomposes programmer-writtentransactions into closed nested transactions, at run-time, to improve performance. The composition of a closed nested transaction depends on the contention of objects, which can change at run-time depending upon the workload at hand. Our implementation and experimental studies reveal that QR-ACN consistently outperforms flat nesting by an averageof 51% on benchmarks including TPC-C. False conflicts occur when high-level operations, even though semantically independent, traverse the same set of objects during transaction execution. Such conflicts can lead torepeated aborts, increasing transaction execution time and degrading performance, which can be significant in DTM, since transaction execution also includes network communication. ii We consider the approach of reducing validation cost for resolving false conflicts. We presentthree protocols for reducing validation cost in DTM. Our first protocol, QR-ON, incorporatesthe open nesting model into QR-DTM. Open nesting allows inner-nested transactions tocommit independently of their parent transaction, releasing objects in the transaction read-set and write-set early, minimizing aborts due to false conflicts. We then present QR-OON,in which open-nested transactions commit asynchronously so that subsequent transactionscan proceed without waiting for the commit of previous transactions. Finally, we presentan early release methodology, QR-ER, in which objects that do not affect the final state ofthe shared data are dropped from the transaction's read-set, which avoids false conflicts andreduces communication costs. Our implementation and experimental studies revealed that QR-OON outperforms QR-ON by up to 43%, and that QR-ER outperforms QR-ON and QR-OON by up to 10% on micro- and macro-benchmarks.","abstract_html":"Distributed Transactional Memory (DTM) is an emerging synchronization abstraction thatpromises to alleviate the scalability, programmability, and composability challenges of lock-based distributed synchronization. With DTM, programmers organize code that read/writeshared memory objects, both local and remote, as memory transactions. An underlying DTMframework guarantees atomicity, isolation, and consistency properties for those transactionsthrough speculative concurrency control. In DTM, restarting an aborted transaction from the beginning can degrade performance astransactional conflicts may have occurred in the later part of the transaction, wasting work.The partial abort method alleviates this difficulty by enabling a transaction to be rolled backto the point where objects in the transaction's read-set and write-set are still consistent.In this thesis, we present protocols for supporting partial aborts in QR-DTM, a fault-tolerant DTM that uses quorum protocols for distributed concurrency control in the presence offailures. We focus on two partial abort models: closed nesting, which allows transactions to be nested and inner transactions to be rolled back without rolling back outer transactions;and checkpointing, which allows the transaction state to be saved in checkpoints throughout execution and transactions to be rolled back to those checkpoints. We present protocols that support these partial abort models in QR-DTM, called QR-CN and QR-CHK. We implemented these protocols and conducted experimental studies using macro-benchmarks(e.g., distributed versions of STAMP benchmark), and micro-benchmarks (e.g., distributed data structures). Our studies reveal that QR-CN improves throughput by as much as 101% over flat nesting in specific cases, with an average improvement of 53%. We also develop QR-ACN, a framework that automatically decomposes programmer-writtentransactions into closed nested transactions, at run-time, to improve performance. The composition of a closed nested transaction depends on the contention of objects, which can change at run-time depending upon the workload at hand. Our implementation and experimental studies reveal that QR-ACN consistently outperforms flat nesting by an averageof 51% on benchmarks including TPC-C. False conflicts occur when high-level operations, even though semantically independent, traverse the same set of objects during transaction execution. Such conflicts can lead torepeated aborts, increasing transaction execution time and degrading performance, which can be significant in DTM, since transaction execution also includes network communication. ii We consider the approach of reducing validation cost for resolving false conflicts. We presentthree protocols for reducing validation cost in DTM. Our first protocol, QR-ON, incorporatesthe open nesting model into QR-DTM. Open nesting allows inner-nested transactions tocommit independently of their parent transaction, releasing objects in the transaction read-set and write-set early, minimizing aborts due to false conflicts. We then present QR-OON,in which open-nested transactions commit asynchronously so that subsequent transactionscan proceed without waiting for the commit of previous transactions. Finally, we presentan early release methodology, QR-ER, in which objects that do not affect the final state ofthe shared data are dropped from the transaction's read-set, which avoids false conflicts andreduces communication costs. Our implementation and experimental studies revealed that QR-OON outperforms QR-ON by up to 43%, and that QR-ER outperforms QR-ON and QR-OON by up to 10% on micro- and macro-benchmarks.","abstract_has_math":false,"creators":["Dhoke, Aditya Anil"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Computer Science and Applications","degree_department":"Computer Science","school":null,"contributors":[],"advisors":[],"committee_chairs":["Tilevich, Eli","Ravindran, Binoy"],"committee_members":["Feng, Wu-chun"],"year":2013,"date_issued":"2013-09-30","date_published":"2013-09-30","updated_at":"2026-07-22T22:19:06Z","subjects":["Software Transactional Memory","Partial Abort","Validation","Closed Nesting","Checkpointing"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:1671"],"render_values":[{"text":"vt_gsexam:1671","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/23890","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Tilevich, Eli","Ravindran, Binoy"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Feng, Wu-chun"]},{"key":"dc:contributor.department","label":"Department","values":["Computer Science"]},{"key":"dc:creator","label":"Author","values":["Dhoke, Aditya Anil"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2013-10-11T08:00:12Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2013-10-11T08:00:12Z"]},{"key":"dc:date.issued","label":"Date","values":["2013-09-30"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Computer Science and Applications"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Software Transactional Memory","Partial Abort","Validation","Closed Nesting","Checkpointing"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["vt_gsexam:1671"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/23890"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Distributed Transactional Memory (DTM) is an emerging synchronization abstraction thatpromises to alleviate the scalability, programmability, and composability challenges of lock-based distributed synchronization. With DTM, programmers organize code that read/writeshared memory objects, both local and remote, as memory transactions. An underlying DTMframework guarantees atomicity, isolation, and consistency properties for those transactionsthrough speculative concurrency control. In DTM, restarting an aborted transaction from the beginning can degrade performance astransactional conflicts may have occurred in the later part of the transaction, wasting work.The partial abort method alleviates this difficulty by enabling a transaction to be rolled backto the point where objects in the transaction's read-set and write-set are still consistent.In this thesis, we present protocols for supporting partial aborts in QR-DTM, a fault-tolerant DTM that uses quorum protocols for distributed concurrency control in the presence offailures. We focus on two partial abort models: closed nesting, which allows transactions to be nested and inner transactions to be rolled back without rolling back outer transactions;and checkpointing, which allows the transaction state to be saved in checkpoints throughout execution and transactions to be rolled back to those checkpoints. We present protocols that support these partial abort models in QR-DTM, called QR-CN and QR-CHK. We implemented these protocols and conducted experimental studies using macro-benchmarks(e.g., distributed versions of STAMP benchmark), and micro-benchmarks (e.g., distributed data structures). Our studies reveal that QR-CN improves throughput by as much as 101% over flat nesting in specific cases, with an average improvement of 53%. We also develop QR-ACN, a framework that automatically decomposes programmer-writtentransactions into closed nested transactions, at run-time, to improve performance. The composition of a closed nested transaction depends on the contention of objects, which can change at run-time depending upon the workload at hand. Our implementation and experimental studies reveal that QR-ACN consistently outperforms flat nesting by an averageof 51% on benchmarks including TPC-C. False conflicts occur when high-level operations, even though semantically independent, traverse the same set of objects during transaction execution. Such conflicts can lead torepeated aborts, increasing transaction execution time and degrading performance, which can be significant in DTM, since transaction execution also includes network communication. ii We consider the approach of reducing validation cost for resolving false conflicts. We presentthree protocols for reducing validation cost in DTM. Our first protocol, QR-ON, incorporatesthe open nesting model into QR-DTM. Open nesting allows inner-nested transactions tocommit independently of their parent transaction, releasing objects in the transaction read-set and write-set early, minimizing aborts due to false conflicts. We then present QR-OON,in which open-nested transactions commit asynchronously so that subsequent transactionscan proceed without waiting for the commit of previous transactions. Finally, we presentan early release methodology, QR-ER, in which objects that do not affect the final state ofthe shared data are dropped from the transaction's read-set, which avoids false conflicts andreduces communication costs. Our implementation and experimental studies revealed that QR-OON outperforms QR-ON by up to 43%, and that QR-ER outperforms QR-ON and QR-OON by up to 10% on micro- and macro-benchmarks."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["ETD"]},{"key":"dc:title","label":"Title","values":["On Partial Aborts and Reducing Validation Costs in Fault-tolerant Distributed Transactional Memory"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Tilevich, Eli","Ravindran, Binoy"],"dc:contributor.committeemember":["Feng, Wu-chun"],"dc:contributor.department":["Computer Science"],"dc:creator":["Dhoke, Aditya Anil"],"dc:date.accessioned":["2013-10-11T08:00:12Z"],"dc:date.available":["2013-10-11T08:00:12Z"],"dc:date.issued":["2013-09-30"],"dc:description.abstract":["Distributed Transactional Memory (DTM) is an emerging synchronization abstraction thatpromises to alleviate the scalability, programmability, and composability challenges of lock-based distributed synchronization. With DTM, programmers organize code that read/writeshared memory objects, both local and remote, as memory transactions. An underlying DTMframework guarantees atomicity, isolation, and consistency properties for those transactionsthrough speculative concurrency control. In DTM, restarting an aborted transaction from the beginning can degrade performance astransactional conflicts may have occurred in the later part of the transaction, wasting work.The partial abort method alleviates this difficulty by enabling a transaction to be rolled backto the point where objects in the transaction's read-set and write-set are still consistent.In this thesis, we present protocols for supporting partial aborts in QR-DTM, a fault-tolerant DTM that uses quorum protocols for distributed concurrency control in the presence offailures. We focus on two partial abort models: closed nesting, which allows transactions to be nested and inner transactions to be rolled back without rolling back outer transactions;and checkpointing, which allows the transaction state to be saved in checkpoints throughout execution and transactions to be rolled back to those checkpoints. We present protocols that support these partial abort models in QR-DTM, called QR-CN and QR-CHK. We implemented these protocols and conducted experimental studies using macro-benchmarks(e.g., distributed versions of STAMP benchmark), and micro-benchmarks (e.g., distributed data structures). Our studies reveal that QR-CN improves throughput by as much as 101% over flat nesting in specific cases, with an average improvement of 53%. We also develop QR-ACN, a framework that automatically decomposes programmer-writtentransactions into closed nested transactions, at run-time, to improve performance. The composition of a closed nested transaction depends on the contention of objects, which can change at run-time depending upon the workload at hand. Our implementation and experimental studies reveal that QR-ACN consistently outperforms flat nesting by an averageof 51% on benchmarks including TPC-C. False conflicts occur when high-level operations, even though semantically independent, traverse the same set of objects during transaction execution. Such conflicts can lead torepeated aborts, increasing transaction execution time and degrading performance, which can be significant in DTM, since transaction execution also includes network communication. ii We consider the approach of reducing validation cost for resolving false conflicts. We presentthree protocols for reducing validation cost in DTM. Our first protocol, QR-ON, incorporatesthe open nesting model into QR-DTM. Open nesting allows inner-nested transactions tocommit independently of their parent transaction, releasing objects in the transaction read-set and write-set early, minimizing aborts due to false conflicts. We then present QR-OON,in which open-nested transactions commit asynchronously so that subsequent transactionscan proceed without waiting for the commit of previous transactions. Finally, we presentan early release methodology, QR-ER, in which objects that do not affect the final state ofthe shared data are dropped from the transaction's read-set, which avoids false conflicts andreduces communication costs. Our implementation and experimental studies revealed that QR-OON outperforms QR-ON by up to 43%, and that QR-ER outperforms QR-ON and QR-OON by up to 10% on micro- and macro-benchmarks."],"dc:description.degree":["Master of Science"],"dc:format.medium":["ETD"],"dc:identifier.other":["vt_gsexam:1671"],"dc:identifier.uri":["http://hdl.handle.net/10919/23890"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["Software Transactional Memory","Partial Abort","Validation","Closed Nesting","Checkpointing"],"dc:title":["On Partial Aborts and Reducing Validation Costs in Fault-tolerant Distributed Transactional Memory"],"dc:type":["Thesis"],"thesis:degree_discipline":["Computer Science and Applications"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:06Z"}