Towards a software transactional memory for graphics processors. Software managed means these caches are not cache coherent, and must be manually flushed. Scheduling techniques for gpu architectures with processing. The evolution of memory technology means we may be about to witness the next wave in computing and storage paradigms. Software transactional memory for gpu architectures nilanjan. Accelerating gpu hardware transactional memory with snapshot. There are three ways to copy data to the gpu memory, either implicitly through calresmapcalresunmap or explicitly via calctxmemcopy or via a custom copy shader that reads from pcie memory and writes to gpu memory. Cederman, tsigas and chaudhry towards a software transactional memory for graphics processors commit operations are often performed indirectly, as in figure1, where they are part of the atomic keyword. An integrated hardwaresoftware approach to flexible. Efficient transactionalmemorybased implementation of morph. Modern gpus have shown promising results in accel erating computation intensive and numerical workloads with limited dynamic data sharing. Gpu localtm allocates transactional metadata in the existing memory resources, minimizing the storage requirements for tm support. An efficient software transactional memory using committime invalidation.
The architecture and evolution of cpugpu systems for. Because of the gpu architecture, certain types of con. Software transactional memory for gpu architectures cgo, orlando, usa. Transactional memory addresses the problem a different way, by allowing multiple threads to access or update the protected data, and guaranteeing the updates appear atomically to all other threads.
Highend embedded systems, like their generalpurpose counterparts, are turning to manycore clusterbased shared memory architectures that provide a shared memory abstraction subject to nonuniform memory access costs. We introduce mosaic, a gpu memory manager that provides applicationtransparent support for multiple page sizes. Transactional synchronization extensions tsx, also called transactional synchronization extensions new instructions tsxni, is an extension to the x86 instruction set architecture isa that adds hardware transactional memory support, speeding up execution of. You can sequence two transactions to build a larger atomic transaction. The coupled cpugpu architecture integrates a cpu and a gpu into the same chip, where the two processors are able to share the same physical memory.
Scheduling techniques for gpu architectures with processinginmemory capabilities ashutosh pattnaik1 xulong tang1 adwait jog2 onur kay. Improvements in hardware transactional memory for gpu architectures alejandro villegas, rafael asenjo, angeles navarro and oscar plata 19th workshop on compilers for parallel computing cpc16, valladolid spain, july 2016. Hardware support for scratchpad memory transactions on gpu. For that matter, the gpu memory is usually uncached, except for the software managed caches inside the gpu, like the texture caches. Cpugpu architectures, data for gpu processing should be transferred to the gpu memory via pcie bus, which is considered as one of the largest overhead for gpu execution 4. You can compose transactions together in multiple ways to build larger transactions. Publications software analytics and pervasive parallelism lab. Gpu access to cpu memory like this is usually quite slow. We have also used aou alone to create a simpler rtmlite. To make applications with dynamic data sharing among threads benefit from gpu acceleration, we propose a novel software transactional memory system for gpu architectures gpustm. A cuda program starts on a cpu and then launches parallel compute kernels onto a gpu.
However, when deciding how to implement the functionality behind these operations, there are several important. Modern gpus have shown promising results in accelerating computation intensive and numerical workloads with limited dynamic data sharing. In a nutshell, intel tsx provides transactional memory support in hardware, making the lives of developers who need to write synchronization codes for concurrent and parallel applications easier. Architecting the lastlevel cache for gpus using sttram technology mohammad hossein samavatian, mohammad arjomand, ramin bashizade, and hamid sarbaziazad, sharif university of technology, iran future gpus should have larger l2 caches based on the current trends in vlsi technology and gpu architectures toward increase of processing core count. Both groups discussed a database software architecture that is capable of making use of multiple hardware devices gpu, tpu, fpga, asics, in addition to the cpu for handling database workloads. We propose gpulocaltm, a hardware transactional memory tm, as an alternative to data locking mechanisms in local memory. The great simon peytonjones and tim harris explained to me the thinki.
In addition, it ensures forward progress through an automatic serialization mechanism. Transactional synchronization extensions tsx, also called transactional synchronization extensions new instructions tsxni, is an extension to the x86 instruction set architecture isa that adds hardware transactional memory support, speeding up execution of multithreaded software through lock elision. Hardware transactional memory htm piggybacks on existing features in cpu microarchitectures to support transactions 17. One notable theoretical foundation to these methods is types of dependency graphs, the read dependency graph 5, which represents the relative serialization order of transactions. Following this, we show how each sm performs a parallel merge and how to divide the work so that all the gpu s streaming processors sp are utilized. The architecture and evolution of cpugpu systems for general. This implies that gpu address translation must support physicallyaddressed caches. Hardware support for local memory transactions on gpu architectures alejandro villegas angeles navarro. Hardware transactional memory for gpu architectures ubc ece. Transactional synchronization extensions wikipedia. Hardware transactional memory architecture with adaptive. Oct 07, 20 transactional memory addresses the problem a different way, by allowing multiple threads to access or update the protected data, and guaranteeing the updates appear atomically to all other threads.
In order to keep the cores and memory hierarchy simple, manycore embedded systems tend to employ simple, scratchpadlike memories, rather than hardware managed. Mosaic uses base pages to transfer data over the system io bus, and allocates physical memory in a way that 1 preserves base page contiguity and 2 ensures that a large page frame contains pages from only a single memory. Aamodt university of british columbia, canada motivation. Cpu gpu architectures, data for gpu processing should be transferred to the gpu memory via pcie bus, which is considered as one of the largest overhead for gpu execution 4. Graphics processing unit gpu memory hierarchy presented by vu dinh and donald macintyre 1. It is only accessible by the gpu and not accessible via the cpu. Hardware transactional memory for gpu architectures. Architecting the lastlevel cache for gpus using sttram. Accelerating gpu hardware transactional memory with snapshot isolation isca 17, june 2428, 2017, toronto, on, canada write skew anomaly.
Gpulocaltm allocates transactional metadata in the existing memory resources, minimizing the storage requirements for tm support. Hardware transactional memory exploration in coherencefree. Transactional memory for heterogeneous cpu gpu systems ricardo manuel nunes vieira thesis to obtain the master of science degree in electrical and computer engineering. Recently, several groups have used this architecture to achieve memory.
Across a range of microbenchmarks, rtm outperforms rstm, a publicly available software transactional memory system, by as much as 8. Software transactional memory for gpu architectures yunlong xu. Ellesmere, 8169 mb available, 36 compute units so what do i do to fix this. Hardware support for local memory transactions on gpu. Scheduling techniques for gpu architectures with processinginmemory capabilities its a promising approach to minimize data movement. Vmm emulation of intel hardware transactional memory. Software transactional memory for gpu architectures proceedings. Rafael ubal david kaeli department of electrical and computer engineering. Accelerating gpu hardware transactional memory with.
Towards a software transactional memory for heterogeneous. Software transactional memory for gpu architectures ieee. The key idea is to transform global synchronization into global communication so that. Abdelrahman, the use of hardware transactional memory for the tracebased parallelization of recursive java programs, proc. Database architectures for modern hardware dagstuhl. The concept dates back to the late 1960s technological limitations of integrating fast computational units in memory was a challenge significant advances in adoption of 3dstacked memory has. Therefore, we study gpu mmus where tlbs are accessed in parallel with the l1 cache. Handling conflicts with compilers help in software transactional memory.
Sep 15, 2008 3 the graphics memory is the gpu s version of host memory. We propose gpu localtm, a hardware transactional memory tm, as an alternative to data locking mechanisms in local memory. Dec 29, 2008 a few years ago i got the chance to learn about software transactional memory for the first time while visiting msr cambridge. Accessible to software engineers and developers as well as students in it disciplines, this book enhances readers understanding of the hardware.
Automatic optimization of software transactional memory through linear regression and decision tree. Proceedings of the 4th international workshop on runtime and operating systems for supercomputers, ross 2014 in conjunction with ics 2014. Architectural support for address translation on gpus. The major challenges include ensuring good scalability with respect to the massively multithreading of gpus, and preventing livelocks caused by the simt execution paradigm of gpus. Pdf software transactional memory for gpu architectures. Highend embedded systems, like their generalpurpose counterparts, are turning to manycore clusterbased sharedmemory architectures that provide a shared memory abstraction subject to nonuniform memory access costs. Software transactional memory for gpu architectures acm digital. This gives some of the benefits of finegrained locking without having to make changes to the code beyond replacing the locks. My research interests are in specialized hardware accelerators, emerging memorystorage technologies, hardwaresoftware codesign, operating systems, virtualization and distributed systems. Gpuaccelerated data management under the test of time cidr. Hardware lock elision hle and restricted transactional memory rtm. Download for offline reading, highlight, bookmark or take notes while you read structured computer organization. One notable theoretical foundation to these methods is types of dependency graphs, the read dependency graph 5. The distributed memory acts as a transactional memory in the individual cache on each processor, whereas for shared memory, transactions are kept in the same memory.
An integrated hardwaresoftware approach to flexible transactional memory. Ourapproach our goal is to provide to the gpu the same programmability bene. Ennals, efficient software transactional memory, technical report, intel research cambridge, uk, 2005. An analytical model for a gpu architecture with memorylevel. Jul 25, 20 in a nutshell, intel tsx provides transactional memory support in hardware, making the lives of developers who need to write synchronization codes for concurrent and parallel applications easier. Each kernel launch dispatches a hierarchy of threads. He also describes virtualization and cloud computing and the emergence of softwarebased systems architectures. Transactional memory for heterogeneous cpugpu systems ricardo manuel nunes vieira thesis to obtain the master of science degree in electrical and computer engineering. The key idea is to transform global synchronization into global communication so that conflicts are serialized at the thread block level. Hardware support for local memory transactions on gpu architectures alejandro villegas, angeles navarro, rafael asenjo plaza, oscar plata, rafael ubal, david kaeli 10th acm sigplan workshop on transactional computing transact, portland, 2015. The new algorithm demonstrates good utilization of the gpu memory hierarchy. Transactional memory for heterogeneous cpugpu systems. Software transactional memory for gpu architectures. Following this, we show how each sm performs a parallel merge and how to divide the work so that all the gpus streaming processors sp are utilized.
Distributed memory would require a mechanism to synchronize or compare data among individual caches, which is not present in shared memory model. This paper extends the reach of general purpose gpu programming by presenting a software architecture that supports efficient finegrained synchronization over global memory. Fun with intel transactional synchronization extensions. The coupled cpu gpu architecture integrates a cpu and a gpu into the same chip, where the two processors are able to share the same physical memory. To evaluate tlll, we use it to implement six widely used programs, and compare it with the stateoftheart adhoc gpu synchronization, gpu software transactional memory stm, and cpu hardware. A few years ago i got the chance to learn about software transactional memory for the first time while visiting msr cambridge. In order to keep the cores and memory hierarchy simple, manycore embedded systems tend to employ simple, scratchpadlike memories, rather than hardware managed caches that. Towards a software transactional memory for graphics. We extend gpu software transactional memory to al low threads across many gpus to access a coherent distributed shared memory space and. A highthroughput dynamic memory allocator for gpgpu. Haskell also provides softwaretransactional memory, which allows programmers build composable and atomic memory transactions. Stm software transactional memory htm hardware transactional memory hytm hybrid transactional memory tsx intels transactional synchronization extensions. Govindarajan, variable granularity access tracking scheme for improving the performance of software transactional memory, in proc.