Trace based phase prediction for tightly-coupled heterogeneous cores

Padmanabha, Shruti; Lukefahr, Andrew; Das, Reetuparna; Mahlke, Scott

doi:10.1145/2540708.2540746

Cited by 45 publications

(15 citation statements)

References 26 publications

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“…First, the scheduling unit in existing techniques is either interval based (fixed-instruction interval [70,72,73,78,81] or fixed-time interval [57,65,79,88,89]) or a code segment (e.g., critical sections, lagging threads, application kernels [54,68,69,87]). The scheduling unit in the event-based scheduling is the event handler in interactive mobile Web applications.…”

Section: Related Workmentioning

confidence: 99%

Event-based scheduling for energy-efficient QoS (eQoS) in mobile Web applications

Zhu

Halpern

Reddi

2015

2015 IEEE 21st International Symposium on High Performance Computer Architecture (HPCA)

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Mobile Web applications have become an integral part of our society. They pose a high demand for application quality of service (QoS). However, the energy-constrained nature of mobile devices makes optimizing for QoS difficult. Prior art on energy efficiency optimizations has only focused on the trade-off between raw performance and energy consumption, ignoring the application QoS characteristics. In this paper, we propose the concept of energy-efficient QoS (eQoS) to capture the trade-off between QoS and energy consumption. Given the fundamental event-driven nature of mobile Web applications, we further propose event-based scheduling as an optimization framework for eQoS. The event-based scheduling automatically reasons about users' QoS requirements, and accurately slacks the events' execution time to save energy without violating end users' experience. We demonstrate a working prototype using the Google Chromium and V8 framework on the Samsung Exynos 5410 SoC (used in the Galaxy S4 smartphone). Based on real hardware and software measurements, we achieve 41.2% energy saving with only 0.4% of QoS violations perceptible to end users. 137978-1-4799-8930-0/15/$31.00 ©2015 IEEE

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Section: Related Workmentioning

confidence: 99%

Event-based scheduling for energy-efficient QoS (eQoS) in mobile Web applications

Zhu

Halpern

Reddi

2015

2015 IEEE 21st International Symposium on High Performance Computer Architecture (HPCA)

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“…Our solution combines the benefits of both architectural heterogeneity [20] and fast migration of only register state, and contributes a more sophisticated mechanism to estimate the inactive core's performance. Rather than react to performance changes, Padmanabha et al rely on a predictive model for a Composite Cores architecture [23].…”

Section: Heterogeneous Cores Migratory Threadsmentioning

confidence: 99%

Exploring Fine-Grained Heterogeneity with Composite Cores

Lukefahr

Padmanabha

Das

et al. 2016

IEEE Trans. Comput.

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Heterogeneous multicore systems-comprising multiple cores with varying performance and energy characteristicshave emerged as a promising approach to increasing energy efficiency. Such systems reduce energy consumption by identifying application phases and migrating execution to the most efficient core that meets performance requirements. However, the overheads of migrating between cores limit opportunities to coarse-grained phases (hundreds of millions of instructions), reducing the potential to exploit energy efficient cores. We propose Composite Cores, an architecture that reduces migration overheads by bringing heterogeneity into a core. Composite Cores pairs a big and little compute µEngine that together achieve high performance and energy efficiency. By sharing architectural state between the µEngines, the migration overhead is reduced, enabling fine-grained migration and increasing the opportunities to utilize the little µEngine without sacrificing performance. An intelligent controller migrates the application between µEngines to maximize energy efficiency while constraining performance loss to a configurable bound. We evaluate Composite Cores using cycle accurate microarchitectural simulations and a detailed power model. Results show that, on average, Composite Cores are able to map 30% of the execution time to the little µEngine, achieving a 21% energy savings while maintaining 95% performance.

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“…A dynamic approach can be more flexible; for example, training on-line predictors to give a runtime performance estimate based on per-region statistics. Other works have shown such mechanisms to be highly effective [23,28], and we therefore do not evaluate or implement this aspect of the compiler/runtime. Instead, we use an oracle scheduler, as described in the evaluation.…”

Section: Region Selectionmentioning

confidence: 99%

Exploring the potential of heterogeneous von neumann/dataflow execution models

NowatzkiTony¹,

GangadharVinay²,

SankaralingamKarthikeyan³

2015

SIGARCH Comput. Archit. News

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General purpose processors (GPPs), from small inorder designs to many-issue out-of-order, incur large power overheads which must be addressed for future technology generations. Major sources of overhead include structures which dynamically extract the data-dependence graph or maintain precise state. Considering irregular workloads, current specialization approaches either heavily curtail performance, or provide simply too little benefit. Interestingly, well known explicit-dataflow architectures eliminate these overheads by directly executing the data-dependence graph and eschewing instruction-precise recoverability. However, even after decades of research, dataflow architectures have yet to come into prominence as a solution. We attribute this to a lack of effective control speculation and the latency overhead of explicit communication, which is crippling for certain codes.This paper makes the observation that if both out-of-order and explicit-dataflow were available in one processor, many types of GPP cores can benefit from dynamically switching during certain phases of an application's lifetime. Analysis reveals that an ideal explicit-dataflow engine could be profitable for more than half of instructions, providing significant performance and energy improvements. The challenge is to achieve these benefits without introducing excess hardware complexity. To this end, we propose the Specialization Engine for Explicit-Dataflow (SEED). Integrated with an inorder core, we see 1.67× performance and 1.65× energy benefits, with an Out-Of-Order (OOO) dual-issue core we see 1.33× and 1.70×, and with a quad-issue OOO, 1.14× and 1.54×.

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Trace based phase prediction for tightly-coupled heterogeneous cores

Cited by 45 publications

References 26 publications

Event-based scheduling for energy-efficient QoS (eQoS) in mobile Web applications

Event-based scheduling for energy-efficient QoS (eQoS) in mobile Web applications

Exploring Fine-Grained Heterogeneity with Composite Cores

Exploring the potential of heterogeneous von neumann/dataflow execution models

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