Apache ignite is an open source inmemory data fabric which provides a wide variety of computing solutions including an inmemory data grid, compute grid, streaming, as well as acceleration solutions for hadoop and spark. Method hardware transactional memory provides a way for victim application to detect and get control to protect itself proactively when its data is evicted out of cache. Both caches are primary caches accessed directly by the processor, and secondary caches may exist between them andthe memory. Transactional memory is a programming model that attempts to make parallel programming easier. This library implements software transactional memory, often abbreviated with stm. It is the first to integrate a software transactional memory system with a mallocfree based memory allocator. Pdf timebased software transactional memory researchgate. Therein he describes a hardware based transactional memory system. Read simon marlows parallel and concurrent programming in haskell for more info. However, the fragility of tsx transactions introduces extra cacheclogging denialofservice dos threats, and attackers could sharply degrade the performance by concurrent memoryintensive tasks.
Apache spark is an open source fast and general engine for largescale data processing. Case studies of applying the solution to the aes, rsa and. Cache sensitive software transactional memory core. Pdf software transactional memory stm is a concurrency control mechanism that is widely. For the haswell microarchitecture the scope of a transaction is limited, because the readwrite set, i. Make use of this cache by setting expire header and etag. We present a new algorithm for implementing object based software transactional memory stm that we have found to significantly outperform the previous best performing algorithms. We achieve this by taking care to minimise cache contention and memorybandwidth requirements. A cache coherence simulator with transactional memory. Not be obstructionfree cache sensitive software transactional memory. Both old and new versions of memory can be victimized transparently because the cache holds no inaccessible transactional state. Cache coherence in distributed and replicated transactional memory systems.
Existing tms may abort many transactions that could, in fact, commit without violating correctness. Software transactional memory stm systems have emerged as a powerful paradigm to. Especially the chapter about performance is also important for using stm in rust. Software transactional memory should not be obstructionfree cache sensitive software transactional. In computer science, software transactional memory stm is a concurrency control mechanism analogous to database transactions for controlling access to shared memory in concurrent computing. Exploiting hardware transactional memory in mainmemory. Threads synchronize by means of memory transactions, shortlived computations that either commit take effect or abort have no effect. Leveraging hardware transactional memory for cache side. We ensure permanent cache residency of sensitive code and data using widely available hardware transactional memory htm, which was originally designed for highperformance concurrency. Feb 17, 2005 software transactional memory stm is an api for multithreaded computation in which shared data is synchronized without using locks.
For all three memory systems, performance with the generated. Most web browsers use a cache to load regularly viewed webpages fast. The approach described in this paper, software transactional memory stm, enables developers to operate on the memory in a similar way to using database transactions. When run on our 106processor test machine, our algorithm is almost five times as fast as the previous. Replacing conventional, cache line oriented coherence protocols and conventional shared memory consistency models with a transactional memory coherence and consistency tcc model can accomplish this. Similarly, the ability to save and restore signatures allows unbounded nesting. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Typical implementations use hardware transactional memory where supported and to the limits that it is available e. We show that cloak provides strong protection against all known cache based sidechannel attacks with low performance overhead. A softwarelevel solution leveraging hardware transactional memory features in commodity processor to enable a program to protect itself from a wide range of cache sidechannel attacks. Abstract cachebased sidechannel attacks are a serious problem in multitenant environments, for example, modern cloud data centers. Spark is for nontransactional, readonly data rdds dont support inplace mutation, while ignite supports both nontransactional olap payloads as well as fully acid compliant.
Probe, flushreload, evicttime, cachecollision attacks. This optimization improves the memory cache hit rate if the. We further study what kinds of spare aborts can be avoided. Unfortunately, there isnt a released, working, usable framework for this yet. Transactions avoid many of these problems, and therefore, promise to ease concurrent programming. This leads us to make very different often counterintuitive choices to other stms, and allows our algorithm to cause very little additional cache contention overhead, relative to a nontransactional program. This library implements software transactional memory, often abbreviated with stm it is designed closely to haskells stm library. Jun 20, 2016 ignite, on the other hand, provides a distributed inmemory keyvalue store distributed cache or data grid with acid transactions and sql querying capabilities. To the best of our knowledge, mimosa is the first to use transactional memory to protect sensitive data against memory attacks. We show that cloak provides strong protection against all known cachebased sidechannel attacks with low performance overhead. Localitysensitive signatures for transactional memory. Cloak relies on the sgx enclave developer to annotate sensitive memory. Johannes schneider march 16 th, 2011 ioana giurgiu softwrae transactional memory.
Researchers have proposed several different implementations of transactional memory, broadly classified into software transactional memory stm and hardware transactional memory htm. A programs use of cpu caches may reveal its memory access pattern and thus leak sensitive information when the program performs secretdependent. This effectively conceals cache accesspatterns from attackers and keeps the performance impact low. We describe a software transactional memory stm system that is part of mcrt, an experimental multicore runtime. Replacing conventional, cacheline oriented coherence protocols and conventional shared memory consistency models with a transactional memory coherence and consistency tcc model can accomplish this. The cache coherence simulator simulates a multiprocessor snoopingbased system that uses the mesi cache coherence protocol with a split transaction bus. When run on our 106processor test machine, our algorithm is almost five times as fast as the previous best known algorithm. Transactional memory provides a concurrency control mechanism that avoids many of the pitfalls of lockbased synchronization.
Localitysensitive signatures for transactional memory conference paper pdf available in ieee transactions on computers 622. Protecting private keys against memory disclosure attacks. We show that cloak provides strong protection against all known. The idea to implement memory operations in a transactional way originates from a 1986 patent by tom knight 1. The lightweight transaction library libltx, a c implementation by robert ennals focusing on efficiency and based on his papers software transactional memory should not be obstructionfree and cache sensitive software transactional memory. Single copy distributed software transactional memory protocol maintains only one replica of each object in the system and is therefore prone to failures in large scale dynamically changing network. Multiversioning in transactional memory request pdf. Intel clear video hd technology, like its predecessor, intel clear video technology, is a suite of image decode and processing technologies built into the integrated processor graphics that improve video playback, delivering cleaner, sharper images, more natural, accurate, and vivid colors, and a clear and stable video picture. A transaction in this context is a piece of code that executes a series of reads and writes to shared memory.
Second, at least the current hardware implementations of transactional memory are limited. Transactions avoid the wellknown problems of locking, including deadlock. Usenix security 17 strong and efficient cache sidechannel. Decoupling hardware transactional memory from caches. Single copy distributed software transactional memory protocol maintains only one replica of each object in the system and is therefore prone to failures in. Tsx abort operations can return a code that indicates the proximate cause, to help diagnosing hardware and software bugs, and debugger support is an integral part of the specification. When run on our 106processor test machine, our algorithm is almost five times. Software transactional memory ransactionalt locking ii dice et. Cloak 28 uses transactional memory to render an attackers cache observations oblivious, before accessing sensitive memory content all cache lines are accessed.
We classify what kinds of spare aborts can be eliminated, and which cannot. A software transactional memory stm is a shared object which behaves like a memory that supports muldequeue begintransaction deleteditemread transactional head if deleteditemnull returnedvalueempty else. Citeseerx cache sensitive software transactional memory. However, the fragility of tsx transactions introduces extra cache clogging denialofservice dos threats, and attackers could sharply degrade the performance. Especially the chapter about performance is also important for using stm in rust with locks the sequential. Cache memory is a type of memory used to hold frequently used data. The overhead for using this design approach was small.
Raccoon 58 attempts to hide accesses to developerannotated data. Thus this paper describes a memory allocator that is suitable for emerging multicore applications, while supporting modern concurrency constructs. Libcmt, an opensource implementation in c by duilio protti based on composable memory transactions. Should not be obstructionfree and cache sensitive software transactional memory. The tcc system is described in detail in section 2 of this paper, and compared further with stateoftheart coherence and consis. Inoursimulations,theregular cache is a conventional directmapped cache. Software transactional memory wikimili, the best wikipedia. It sounds like youre remembering the discussion of software transactional memory from. Then, the process uses an nonblocking kword readmodify write atomic operation which checks if the values contained in the memory are equivalent to the the value read in the cache update. Software transactional memory stm is an api for multithreaded computation in which shared data is synchronized without using locks. In the current architecture of the fenixedu system, every.
Architectural support for software transactional memory. Overall, haswell is more likely to use the cachebased tm system. Previous hardware tm systems were plagued by associativity conflicts, which intel probably dealt with by using the l2 cache for transactional data. Usenix security 17 strong and efficient cache side. Transactional memory is just as complex as simultaneous multithreading, and intels smt was specifically designed so that it could be disabled in early versions e.
Cache based sidechannel attacks are a serious problem in multitenant environments, for example, modern cloud data centers. Method hardware transactional memory provides a way for victim application to detect and get control to protect itself proactively when its data is. A software transactional memory stm is a shared object which behaves like a memory that supports muldequeue begintransaction deleteditemreadtransactionalhead if deleteditemnull returnedvalueempty else ritetransactionalhead, deleteditemc. Transactional memory is originally proposed as a speculative. Logtmse achieves this using an additional summary signature per thread context to sum. Transactional memory uses either eager at encounter time or lazy at commit time validation to check for conflicting accesses between concurrent transactions, and researchers have been divided over which approach is best. The simulator models a multiprocessor system, where each processor has a variable sized l1 4way associative lru cache.
However, the fragility of tsx transactions introduces extra cacheclogging denialofservice dos threats, and attackers could sharply degrade the performance. Software transactional memory stm is a mechanism used to coordinate. Performance modelling of hardware transactional memory. A hardware transactional memory htm system uses multiword synchronization operations of the cpu to implement the requirements of the transaction directly e. In particular, we use intel transactional synchronization extensions tsx 40, a commodity implementation of htm in commercialofftheshelf cots platforms. Software transactional memory wikipedia, the free encyclopedia. Strong and efficient cache sidechannel protection using. To the best of our knowledge, mimosa is the first to use transactional memory to protect sensitive. Stm is a strategy implemented in software, rather than as a hardware component. Many cache side channel attacks involve adversary evicting victims cache lines during the execution of sensitive operations. This paper takes a step toward developing a theory for understanding aborts in transactional memory systems tms.