243 research outputs found
Enabling preemptive multiprogramming on GPUs
GPUs are being increasingly adopted as compute accelerators in many domains, spanning environments from mobile systems to cloud computing. These systems are usually running multiple applications, from one or several users. However GPUs do not provide the support for resource sharing traditionally expected in these scenarios. Thus, such systems are unable to provide key multiprogrammed workload requirements, such as responsiveness, fairness or quality of service. In this paper, we propose a set of hardware extensions that allow GPUs to efficiently support multiprogrammed GPU workloads. We argue for preemptive multitasking and design two preemption mechanisms that can be used to implement GPU scheduling policies. We extend the architecture to allow concurrent execution of GPU kernels from different user processes and implement a scheduling policy that dynamically distributes the GPU cores among concurrently running kernels, according to their priorities. We extend the NVIDIA GK110 (Kepler) like GPU architecture with our proposals and evaluate them on a set of multiprogrammed workloads with up to eight concurrent processes. Our proposals improve execution time of high-priority processes by 15.6x, the average application turnaround time between 1.5x to 2x, and system fairness up to 3.4x.We would like to thank the anonymous reviewers, Alexan-
der Veidenbaum, Carlos Villavieja, Lluis Vilanova, Lluc Al-
varez, and Marc Jorda on their comments and help improving
our work and this paper. This work is supported by Euro-
pean Commission through TERAFLUX (FP7-249013), Mont-
Blanc (FP7-288777), and RoMoL (GA-321253) projects,
NVIDIA through the CUDA Center of Excellence program,
Spanish Government through Programa Severo Ochoa (SEV-2011-0067) and Spanish Ministry of Science and Technology
through TIN2007-60625 and TIN2012-34557 projects.Peer ReviewedPostprint (authorโs final draft
A scheduling theory framework for GPU tasks e๏ฌcient execution
Concurrent execution of tasks in GPUs can reduce the computation time of a workload by
overlapping data transfer and execution commands.
However it is di๏ฌcult to implement an e๏ฌcient run-
time scheduler that minimizes the workload makespan
as many execution orderings should be evaluated. In
this paper, we employ scheduling theory to build a
model that takes into account the device capabili-
ties, workload characteristics, constraints and objec-
tive functions. In our model, GPU tasks schedul-
ing is reformulated as a ๏ฌow shop scheduling prob-
lem, which allow us to apply and compare well known
methods already developed in the operations research
๏ฌeld. In addition we develop a new heuristic, specif-
ically focused on executing GPU commands, that
achieves better scheduling results than previous tech-
niques. Finally, a comprehensive evaluation, showing
the suitability and robustness of this new approach,
is conducted in three di๏ฌerent NVIDIA architectures
(Kepler, Maxwell and Pascal).Proyecto TIN2016- 0920R, Universidad de Mรกlaga (Campus de Excelencia Internacional Andalucรญa Tech) y programa de donaciรณn de NVIDIA Corporation
Supporting Preemptive Task Executions and Memory Copies in GPGPUs
GPGPUs (General Purpose Graphic Processing Units) provide massive computational power. However, applying GPGPU technology to real-time computing is challenging due to the non-preemptive nature of GPGPUs. Especially, a job running in a GPGPU or a data copy between a GPGPU and CPU is non-preemptive. As a result, a high priority job arriving in the middle of a low priority job execution or memory copy suffers from priority inversion. To address the problem, we present a new lightweight approach to supporting preemptive memory copies and job executions in GPGPUs. Moreover, in our approach, a GPGPU job and memory copy between a GPGPU and the hosting CPU are run concurrently to enhance the responsiveness. To show the feasibility of our approach, we have implemented a prototype system for preemptive job executions and data copies in a GPGPU. The experimental results show that our approach can bound the response times in a reliable manner. In addition, the response time of our approach is significantly shorter than those of the unmodified GPGPU runtime system that supports no preemption and an advanced GPGPU model designed to support prioritization and performance isolation via preemptive data copies
A C-DAG task model for scheduling complex real-time tasks on heterogeneous platforms: preemption matters
Recent commercial hardware platforms for embedded real-time systems feature
heterogeneous processing units and computing accelerators on the same
System-on-Chip. When designing complex real-time application for such
architectures, the designer needs to make a number of difficult choices: on
which processor should a certain task be implemented? Should a component be
implemented in parallel or sequentially? These choices may have a great impact
on feasibility, as the difference in the processor internal architectures
impact on the tasks' execution time and preemption cost. To help the designer
explore the wide space of design choices and tune the scheduling parameters, in
this paper we propose a novel real-time application model, called C-DAG,
specifically conceived for heterogeneous platforms. A C-DAG allows to specify
alternative implementations of the same component of an application for
different processing engines to be selected off-line, as well as conditional
branches to model if-then-else statements to be selected at run-time. We also
propose a schedulability analysis for the C-DAG model and a heuristic
allocation algorithm so that all deadlines are respected. Our analysis takes
into account the cost of preempting a task, which can be non-negligible on
certain processors. We demonstrate the effectiveness of our approach on a large
set of synthetic experiments by comparing with state of the art algorithms in
the literature
๋ฉํฐ ํ์คํน ํ๊ฒฝ์์ GPU๋ฅผ ์ฌ์ฉํ ๋ฒ์ฉ์ ๊ณ์ฐ ์์ฉ์ ํจ์จ์ ์ธ ์์คํ ์์ ํ์ฉ์ ์ํ GPU ์์คํ ์ต์ ํ
ํ์๋
ผ๋ฌธ (๋ฐ์ฌ) -- ์์ธ๋ํ๊ต ๋ํ์ : ๊ณต๊ณผ๋ํ ์ ๊ธฐยท์ปดํจํฐ๊ณตํ๋ถ, 2020. 8. ์ผํ์.Recently, General Purpose GPU (GPGPU) applications are playing key roles in many different research fields, such as high-performance computing (HPC) and deep learning (DL). The common feature exists in these applications is that all of them require massive computation power, which follows the high parallelism characteristics of the graphics processing unit (GPU). However, because of the resource usage pattern of each GPGPU application varies, a single application cannot fully exploit the GPU systems resources to achieve the best performance of the GPU since the GPU system is designed to provide system-level fairness to all applications instead of optimizing for a specific type. GPU multitasking can address the issue by co-locating multiple kernels with diverse resource usage patterns to share the GPU resource in parallel. However, the current GPU mul- titasking scheme focuses just on co-launching the kernels rather than making them execute more efficiently. Besides, the current GPU multitasking scheme is not open-sourced, which makes it more difficult to be optimized, since the GPGPU applications and the GPU system are unaware of the feature of each other. In this dissertation, we claim that using the support from framework between the GPU system and the GPGPU applications without modifying the application can yield better performance. We design and implement the frame- work while addressing two issues in GPGPU applications. First, we introduce a GPU memory checkpointing approach between the host memory and the device memory to address the problem that GPU memory cannot be over-subscripted in a multitasking environment. Second, we present a fine-grained GPU kernel management scheme to avoid the GPU resource under-utilization problem in a
i
multitasking environment. We implement and evaluate our schemes on a real GPU system. The experimental results show that our proposed approaches can solve the problems related to GPGPU applications than the existing approaches while delivering better performance.์ต๊ทผ ๋ฒ์ฉ GPU (GPGPU) ์์ฉ ํ๋ก๊ทธ๋จ์ ๊ณ ์ฑ๋ฅ ์ปดํจํ
(HPC) ๋ฐ ๋ฅ ๋ฌ๋ (DL)๊ณผ ๊ฐ์ ๋ค์ํ ์ฐ๊ตฌ ๋ถ์ผ์์ ํต์ฌ์ ์ธ ์ญํ ์ ์ํํ๊ณ ์๋ค. ์ด๋ฌํ ์ ์ฉ ๋ถ์ผ์ ๊ณตํต์ ์ธ ํน์ฑ์ ๊ฑฐ๋ํ ๊ณ์ฐ ์ฑ๋ฅ์ด ํ์ํ ๊ฒ์ด๋ฉฐ ๊ทธ๋ํฝ ์ฒ๋ฆฌ ์ฅ์น (GPU)์ ๋์ ๋ณ๋ ฌ ์ฒ๋ฆฌ ํน์ฑ๊ณผ ๋งค์ฐ ์ ํฉํ๋ค. ๊ทธ๋ฌ๋ GPU ์์คํ
์ ํน์ ์ ํ์ ์์ฉ ํ๋ก๊ทธ๋จ์ ์ต์ ํํ๋ ๋์ ๋ชจ๋ ์์ฉ ํ๋ก๊ทธ๋จ์ ์์คํ
์์ค์ ๊ณต์ ์ฑ์ ์ ๊ณตํ๋๋ก ์ค๊ณ๋์ด ์์ผ๋ฉฐ ๊ฐ GPGPU ์์ฉ ํ๋ก๊ทธ๋จ์ ์์ ์ฌ์ฉ ํจํด์ด ๋ค์ํ๊ธฐ ๋๋ฌธ์ ๋จ์ผ ์์ฉ ํ๋ก๊ทธ๋จ์ด GPU ์์คํ
์ ๋ฆฌ์์ค๋ฅผ ์์ ํ ํ์ฉํ์ฌ GPU์ ์ต๊ณ ์ฑ๋ฅ์ ๋ฌ์ฑ ํ ์๋ ์๋ค.
๋ฐ๋ผ์ GPU ๋ฉํฐ ํ์คํน์ ๋ค์ํ ๋ฆฌ์์ค ์ฌ์ฉ ํจํด์ ๊ฐ์ง ์ฌ๋ฌ ์์ฉ ํ๋ก๊ทธ ๋จ์ ํจ๊ป ๋ฐฐ์นํ์ฌ GPU ๋ฆฌ์์ค๋ฅผ ๊ณต์ ํจ์ผ๋ก์จ GPU ์์ ์ฌ์ฉ๋ฅ ์ ํ ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ ์ ์๋ค. ๊ทธ๋ฌ๋ ๊ธฐ์กด GPU ๋ฉํฐ ํ์คํน ๊ธฐ์ ์ ์์ ์ฌ์ฉ๋ฅ ๊ด์ ์์ ์ ์ฉ ํ๋ก๊ทธ๋จ์ ํจ์จ์ ์ธ ์คํ๋ณด๋ค ๊ณต๋์ผ๋ก ์คํํ๋ ๋ฐ ์ค์ ์ ๋๋ค. ๋ํ ํ์ฌ GPU ๋ฉํฐ ํ์คํน ๊ธฐ์ ์ ์คํ ์์ค๊ฐ ์๋๋ฏ๋ก ์์ฉ ํ๋ก๊ทธ๋จ๊ณผ GPU ์์คํ
์ด ์๋ก์ ๊ธฐ๋ฅ์ ์ธ์ํ์ง ๋ชปํ๊ธฐ ๋๋ฌธ์ ์ต์ ํํ๊ธฐ๊ฐ ๋ ์ด๋ ค์ธ ์๋ ์๋ค.
๋ณธ ๋
ผ๋ฌธ์์๋ ์์ฉ ํ๋ก๊ทธ๋จ์ ์์ ์์ด GPU ์์คํ
๊ณผ GPGPU ์์ฉ ์ฌ ์ด์ ํ๋ ์์ํฌ๋ฅผ ํตํด ์ฌ์ฉํ๋ฉด ๋ณด๋ค ๋์ ์์ฉ์ฑ๋ฅ๊ณผ ์์ ์ฌ์ฉ์ ๋ณด์ผ ์ ์์์ ์ฆ๋ช
ํ๊ณ ์ ํ๋ค. ๊ทธ๋ฌ๊ธฐ ์ํด GPU ํ์คํฌ ๊ด๋ฆฌ ํ๋ ์์ํฌ๋ฅผ ๊ฐ๋ฐํ์ฌ GPU ๋ฉํฐ ํ์คํน ํ๊ฒฝ์์ ๋ฐ์ํ๋ ๋ ๊ฐ์ง ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ์๋ค. ์ฒซ์งธ, ๋ฉํฐ ํ ์คํน ํ๊ฒฝ์์ GPU ๋ฉ๋ชจ๋ฆฌ ์ด๊ณผ ํ ๋นํ ์ ์๋ ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ๊ธฐ ์ํด ํธ์คํธ ๋ฉ๋ชจ๋ฆฌ์ ๋๋ฐ์ด์ค ๋ฉ๋ชจ๋ฆฌ์ ์ฒดํฌํฌ์ธํธ ๋ฐฉ์์ ๋์
ํ์๋ค. ๋์งธ, ๋ฉํฐ ํ์คํน ํ ๊ฒฝ์์ GPU ์์ ์ฌ์ฉ์จ ์ ํ ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ๊ธฐ ์ํด ๋์ฑ ์ธ๋ถํ ๋ GPU ์ปค๋ ๊ด๋ฆฌ ์์คํ
์ ์ ์ํ์๋ค.
๋ณธ ๋
ผ๋ฌธ์์๋ ์ ์ํ ๋ฐฉ๋ฒ๋ค์ ํจ๊ณผ๋ฅผ ์ฆ๋ช
ํ๊ธฐ ์ํด ์ค์ GPU ์์คํ
์
92
๊ตฌํํ๊ณ ๊ทธ ์ฑ๋ฅ์ ํ๊ฐํ์๋ค. ์ ์ํ ์ ๊ทผ๋ฐฉ์์ด ๊ธฐ์กด ์ ๊ทผ ๋ฐฉ์๋ณด๋ค GPGPU ์์ฉ ํ๋ก๊ทธ๋จ๊ณผ ๊ด๋ จ๋ ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ ์ ์์ผ๋ฉฐ ๋ ๋์ ์ฑ๋ฅ์ ์ ๊ณตํ ์ ์์์ ํ์ธํ ์ ์์๋ค.Chapter 1 Introduction 1
1.1 Motivation 2
1.2 Contribution . 7
1.3 Outline 8
Chapter 2 Background 10
2.1 GraphicsProcessingUnit(GPU) and CUDA 10
2.2 CheckpointandRestart . 11
2.3 ResourceSharingModel. 11
2.4 CUDAContext 12
2.5 GPUThreadBlockScheduling . 13
2.6 Multi-ProcessServicewithHyper-Q 13
Chapter 3 Checkpoint based solution for GPU memory over- subscription problem 16
3.1 Motivation 16
3.2 RelatedWork. 18
3.3 DesignandImplementation . 20
3.3.1 System Design 21
3.3.2 CUDAAPIwrappingmodule 22
3.3.3 Scheduler . 28
3.4 Evaluation. 31
3.4.1 Evaluationsetup . 31
3.4.2 OverheadofFlexGPU 32
3.4.3 Performance with GPU Benchmark Suits 34
3.4.4 Performance with Real-world Workloads 36
3.4.5 Performance of workloads composed of multiple applications 39
3.5 Summary 42
Chapter 4 A Workload-aware Fine-grained Resource Manage- ment Framework for GPGPUs 43
4.1 Motivation 43
4.2 RelatedWork. 45
4.2.1 GPUresourcesharing 45
4.2.2 GPUscheduling . 46
4.3 DesignandImplementation . 47
4.3.1 SystemArchitecture . 47
4.3.2 CUDAAPIWrappingModule . 49
4.3.3 smCompactorRuntime . 50
4.3.4 ImplementationDetails . 57
4.4 Analysis on the relation between performance and workload usage pattern 60
4.4.1 WorkloadDefinition . 60
4.4.2 Analysisonperformancesaturation 60
4.4.3 Predict the necessary SMs and thread blocks for best performance . 64
4.5 Evaluation. 69
4.5.1 EvaluationMethodology. 70
4.5.2 OverheadofsmCompactor . 71
4.5.3 Performance with Different Thread Block Counts on Dif- ferentNumberofSMs 72
4.5.4 Performance with Concurrent Kernel and Resource Sharing 74
4.6 Summary . 79
Chapter 5 Conclusion. 81
์์ฝ. 92Docto
Cooperative kernels: GPU multitasking for blocking algorithms
There is growing interest in accelerating irregular data-parallel algorithms on GPUs. These algorithms are typically blocking , so they require fair scheduling. But GPU programming models (e.g. OpenCL) do not mandate fair scheduling, and GPU schedulers are unfair in practice. Current approaches avoid this issue by exploit- ing scheduling quirks of todayโs GPUs in a manner that does not allow the GPU to be shared with other workloads (such as graphics rendering tasks). We propose cooperative kernels , an extension to the traditional GPU programming model geared towards writing blocking algorithms. Workgroups of a cooperative kernel are fairly scheduled, and multitasking is supported via a small set of language extensions through which the kernel and scheduler cooperate. We describe a prototype implementation of a cooperative kernel frame- work implemented in OpenCL 2.0 and evaluate our approach by porting a set of blocking GPU applications to cooperative kernels and examining their performance under multitasking
Inter-workgroup barrier synchronisation on graphics processing units
GPUs are parallel devices that are able to run thousands of
independent threads concurrently. Traditional GPU programs are
data-parallel, requiring little to no communication,
i.e. synchronisation, between threads. However, classical concurrency
in the context of CPUs often exploits synchronisation idioms that are
not supported on GPUs. By studying such idioms on GPUs, with an aim to
facilitate them in a portable way, a wider and more generic space of
GPU applications can be made possible.
While the breadth of this thesis extends to many aspects of GPU
systems, the common thread throughout is the global barrier: an
execution barrier that synchronises all threads executing a GPU
application. The idea of such a barrier might seem straightforward,
however this investigation reveals many challenges and insights. In
particular, this thesis includes the following studies:
Execution models: while a general global barrier can deadlock due to
starvation on GPUs, it is shown that the scheduling guarantees of
current GPUs can be used to dynamically create an execution
environment that allows for a safe and portable global barrier
across a subset of the GPU threads.
Application optimisations: a set GPU optimisations are examined that
are tailored for graph applications, including one optimisation
enabled by the global barrier. It is shown that these optimisations
can provided substantial performance improvements, e.g. the barrier
optimisation achieves over a 10X speedup on AMD and Intel GPUs. The
performance portability of these optimisations is investigated, as
their utility varies across input, application, and architecture.
Multitasking: because many GPUs do not support preemption,
long-running GPU compute tasks (e.g. applications that use the
global barrier) may block other GPU functions, including graphics. A
simple cooperative multitasking scheme is proposed that allows
graphics tasks to meet their deadlines with reasonable overheads.Open Acces
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