A case for deconstructing hardware transactional memory. At 16 threads, our system with softwaredefined conflicts outperforms logtmse in nearly all benchmarks, reaching an average reduction in execution time of 18%. Stm is a strategy implemented in software, rather than as a hardware component. The second and typically most expensive piece to look at is memory. Moreover, we would appreciate if you cite also the speacial features of gem5 which have been developed and contributed to the main line since the publication of the original paper in 2011. A transaction may execute a number of read andor write operations to memory. Our experiments reveal that leveraging software defined conflicts, the programmer is able to achieve significant reductions in the number of abortsover 50% for most applications. Conflictaware economical unbounded hardware transactional.
Garcia, tim harris, adrian cristal, osman unsal, ibrahim hur, mateo valero, hardware transactional memory with softwaredefined conflicts, acm transactions on architecture and code optimization taco, v. Transactional memory tm is a concurrency control paradigm that provides. Transaction level modelling of sca compliant software defined radio waveforms and platforms pimpsm gg, en, ms, fv. A transactional memory system determines whether to pass control of a transaction to an abouttorunoutofresource handler.
Hardware transactional memory with softwaredefined conflicts. Kr101424902b1 handling operating system os transitions. A transaction in this context occurs when a piece of code executes a series of reads and writes to shared memory. Accelerating gpu hardware transactional memory with. Every transaction is represented by a software descriptor. By recognizing these select papers for their ingenuity and importance, acm highlights some of the theoretical and practical innovations that are likely to shape the future of computing. Hardware supported tsx technology represented by xbegin and xend instructions helps avoid expensive software locks. I dont know it is hardware problem or software problem. Best paper awards are presented at many acm conferences to authors whose work represents groundbreaking research in their respective areas.
As a programming method that can atomicize an arbitrary. Modern cpus support the detection and resolution of memory conflicts between multiple threads that access the same data. The application gets the full power of the unmediated hardware, through an applicationspecific library linked into the application address space. Records reasons for transactional memory abort events for example, from intel tsx transactional memory support. A comprehensive study of conflict resolution policies in hardware. Learn about convergence, software defined storage, and tiered storage options here. Hardware transactional memory, software defined conflicts, transactional conflict. Acm transactions on architecture and code optimization taco jun 2017. I am particularly interested in parallel programming, os runtimesystem i.
Our experiments with several transactional benchmarks reveal that using software defined conflicts, the programmer achieves significant reductions in the number of aborted transactions and improve scalability. Sure, but the tech isnt broadly available yet, and it wouldnt cover everything. Hardware transactional memory with softwaredefined conflicts ruben titosgil, manuel acacio, jose garcia, tim harris, adrian cristal, osman s. Kr101424902b1 handling operating system os transitions in. Hardwaresupported tsx technology represented by xbegin and xend instructions helps avoid expensive software locks. The success of the software defined networks sdn and the network function virtualization nfv paradigms has naturally fueled the model of softwarized networks in which specialized hardware is replaced by generalpurpose platforms and network functions are implemented as software applications instantiated through the network control plane. The hardware appends to the log, and a software handler clears the log when. Characterization of conflicts in logbased transactional memory logtm. Could we cover a number of cases with copyonwrite semantics and system transactional memory. My host is cpu x5680 x 2, 4gb ddriii ram x 18, 300gb sas hd x 8 i install esx4. Us patent for alerting hardware transactions that are.
One wellstudied model of a multiprocessing system involves a fixed number n of identical abstract processors, a finite set of tasks to be executed, each requiring a specified amount of computation time, and a partial ordering on the tasks which requires certain tasks to be completed before certain others can be initiated. If you use gem5 in your research, we would appreciate a citation to the original paper in any publications you produce. A processor of the transactional memory system determines information about an abouttorunoutofresource handler for transaction execution of a code region of a hardware transaction. In this paper we propose conflictdefined blocks, a programming language construct that allows programmers to change the concept of conflict from one transaction to another, or even throughout the course of the same transaction. Hardware transactional memory systems may comprise modifications in. This indicates one of the softwaredefined events provided by the kernel even if no hardware support is available. Hardware transactional memory with softwaredefined conflicts ruben titosgil 1, manuel e. Conflict detection in hardware transactional memory springerlink.
While hardware vendors are actively pursuing providing transaction support at the hardware level, considerable work has been done at the stm level. Conflict detection in hardware transactional memory. Aug 18, 2016 a transactional memory system determines whether to pass control of a transaction to an abouttorunoutofresource handler. Transactional memory with strong atomicity using off. My hardware is supermicro 60263rf it is in the vmware compatibility list. While transactional memory has been investigated intensively, its use as a programming primitive by application and system builders is only recently becoming widespread, especially with the availability of hardware support in mainstream commercial cpus. In computer science and engineering, transactional memory attempts to simplify concurrent. Build my academic paper feedback network github pages. My research interests span multiple layers of the stack. Fault tolerance for multithreaded applications running on transactional memory hardware. A case for deconstructing hardware transactional memory systems, booktitle programming models for.
Jonstobias wamhoff, pascal felber, christof fetzer, gilles muller and etienne riviere. In the code, the block defined by transaction is guaranteed atomicity. Htm implements three out of the four key features required by tls. Hardware transactional memory with softwaredefined. Unsal, ibrahim hur, mateo valero, hipeac 2012, also appears in acm taco, vol 8, no. Hardware transactional memory htm systems reflect choices from three. While offering flexibility and no hardware cost, it leads to overhead in excess of. The nonpreemptive operation of the system is guided by an ordered list.
Data conflicts single dictionary global memory allocator analysis leading to improvements in future hw generations source. Incremental validation is a known method to achieve opacity in tm systems written in software software transactional memory, stm. Garcia, tim harris, adrian cristal, osman unsal, ibrahim hur and mateo valero. Us patent for alerting hardware transactions that are about. Exploiting hardware transactional memory in mainmemory. The nodes are configured to replicate one or more portions of memory. Build my academic paper feedback network 02 june 2017 i sketch through each toplevel storage conferences and try to build a framework to catch world storage technology updates and to quickly filter through large volume of papers and to select good ones. Rebooting the desktop operating system 656 points by daureg on aug. Garcia, tim harris, adrian cristal, osman unsal, ibrahim hur, mateo valero, hardware transactional memory with software defined conflicts, acm transactions on architecture and code optimization taco, v. Opacity of memory management in software transactional. Verification tools for transactional programs springerlink.
A case for deconstructing hardware transactional memory systems. I like this book because it provides an excellent introduction to software transactional memory, detailing the various innovations and issues in this. Siam journal on computing society for industrial and. Efficient gpu hardware transactional memory through early. These reads and writes logically occur at a single instant in time.
Hardware transactional memory with software defined conflicts. Mar 12, 20 the wiretap unit is configured to monitor memory accesses of the processors. When a conflict is detected, a transaction will revert to its initial state prior to any. Defining conflicts in software makes possible the removal of dependencies which, though not necessary for the correct execution of the transactions, arise as a result of the coarse synchronization style encouraged by tm. Modeling handover signaling messages in openflowbased mobile softwaredefined networks. Intel introduces hardware transactional memory htm in mainstream cpus. At 16 threads, our system with software defined conflicts outperforms logtmse in nearly all benchmarks, reaching an average reduction in execution time of 18%. Efficient gpu hardware transactional memory through early conflict resolution. Memory was one of the most confusing values to work with before virtualization, because few tools existed to really tell us what was going on inside our servers. Our experiments reveal that leveraging softwaredefined conflicts, the programmer is able to achieve significant reductions in the number of abortsover 50% for most applications. We present flextm flexible transactional memory, a high performance tm framework that allows software to determine when eagerly, lazily, or in a mixed fashion and how to manage conflicts. Hardware transactional memory with softwaredefined conflicts article pdf available in acm transactions on architecture and code optimization 84.
Refereeing conflicts in hardware transactional memory. Learn about convergence, softwaredefined storage, and tiered storage options here. A call to arms for tackling the unexpected implications of sdn controller enhancements. We describe how to implement a hardware tm design that utilizes this software construct. Fault tolerance for multithreaded applications running on. The os only sets up the execution environment and interacts with an application in rare cases where resources need to be reallocated or name conflicts need to be resolved. Hardware transactional memory with softwaredefined conflicts 5th acm sigplan workshop on transactional computing, transact 2010. Efficient eager management of conflicts for scalable hardware transactional memory.
Hardware transactional memory with softwaredefined conflicts, acm trans. The processor dynamically monitors an amount of available resource for the. Aug 31, 2015 the second and typically most expensive piece to look at is memory. Architecture and code optimization acm transactions on architecture and code optimization vol. Accordingly, on each read of data a transaction validates all its previously read data by a comparison of a formerly taken copy to the current state of the data in memory. Sequential consistency violations, contention for shared memory, true sharing false sharing, hardware transactional memory htm, interconnects, network on chip noc, dynamic voltagefrequency scaling dvfs, chip multiprocessors cmps, photonic interconnects, laser gating technique, power.
Journal of computer networks and communications, vol. While some tm systems operate completely in software stms. However, in a multicore system fitted with a shared lastlevel cache llc, prefetch induced by a core consumes common resources such as shared cache space and main memory bandwidth. Performance pathologies in hardware transactional memory. For timestamp conflicts, which are detected in software. A call to arms for tackling the unexpected implications of. Workshop on exploiting parallelism with transactional memory and other hardware assisted methods epham 2008 in conjunction. Giuseppe demonstrated how to use dbdeployer to setup two mysql ndb clusters very simply, starting them in under 30 seconds and.
One proposed hardware design, warp tm, can scale to s of concurrent transactions. In computer science, software transactional memory is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. The primary reason for this slow adoption is the performance implications of using transactions either through hardware transactional memory htm or software transactional memory stm. The influence of malloc placement on tsx hardware transactional memory. Unlike other resources in a server, memory is often cached for future use. Efficient hardware scheme to support crosscluster transactional memory. Hardware data prefetch is a very well known technique for hiding memory latencies. It is software transactional memory by larus, rajwar and harris, second edition from morgan claypool publishers. In one embodiment, the present invention includes receiving control in kernel mode through a ring transition from a user thread during execution of an unlimited transaction memory utm transaction, updating the state of the transaction state register tsr associated with the user thread, and storing the tsr with the threads state and recovering the situation during the transition from the.
Defining conflicts in software makes possible the removal of dependencies which, though not necessary for the correct execution of the transactions, arise as a. This is called the transactional synchronisation extension tsx in modern intel cpus. Hardware transactional memory with software defined conflicts 5th acm sigplan workshop on transactional computing, transact 2010. Transaction execution aka transactional memory and the. Rebooting the desktop operating system hacker news. A transactional memory with automatic performance tuning. Bernd presented an array of benchmarks showing that mysql ndb cluster continues to be faster than the nosql products invented in response to the claim that sql cannot scale.
Profiling transactional memory applications on an atomic block basis. Speculative execution is supported, however, in the form of hardware transactional memory htm available in processors such as the intel core and the ibm power8. Improving inmemory database index performance with intel transactional synchronization extensions. An analytical model of hardware transactional memory. This months mustread book is also on software transactional memory. In this chapter, the two most common ways of detecting conflicts are described. Streamlining transactions for low thread counts, in 7th acm sigplan workshop on transactional computing. Our experiments with several transactional benchmarks reveal that using softwaredefined conflicts, the programmer achieves significant reductions in the number of aborted transactions and improve scalability. Using hardware transactional memory to correct and simplify and readerswriter lock algorithm dd, yl, yl. Delaunay mesh refinement algorithm described in kulkarni et al. Papers by mateo valero bscmicrosoft research centre. You can browse for and follow blogs, read recent entries, see what others are viewing or recommending, and request your own blog. Opacity of memory management in software transactional memory. Theophilus benson duke university abstract the last few years have seen a massive and organic transformation of the software defined networking ecosystem with the.
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