Energy aware real time scheduling algorithm for mixed task set

Digalwar, Mayuri; Mohan, Sudeept; Raveendran, Biju K.

doi:10.1109/icaes.2013.6659421

“…Second, most real-time DVFS schemes only try to reduce the energy consumption of the CPU, which can be determined analytically, and these schemes do not take into account other devices (such as memory, power supplies, or disk) that consume an important fraction of the total energy used by a server system. Although Digalwar et al [2013] investigated real-time scheduling algorithms for a mixed set of periodic and aperiodic tasks, these schemes were developed for uniprocessor systems.…”

Section: Related Workmentioning

confidence: 99%

Scheduling a Video Transcoding Server to Save Energy

Song

¹

,

Lee

²

2015

ACM Trans. Multimedia Comput. Commun. Appl.

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Recent popular streaming services such as TV Everywhere, N-Screen, and dynamic adaptive streaming over HTTP (DASH) need to deliver content to the wide range of devices, requiring video content to be transcoded into different versions. Transcoding tasks require a lot of computation, and each task typically has its own real-time constraint. These make it difficult to manage transcoding, but the more efficient use of energy in servers is an imperative. We characterize transcoding workloads in terms of deadlines and computation times, and propose a new dynamic voltage and frequency scaling (DVFS) scheme that allocates a frequency and a workload to each CPU with the aim of minimizing power consumption while meeting all transcoding deadlines. This scheme has been simulated, and also implemented in a Linux transcoding server, in which a frontend node distributes transcoding requests to heterogeneous backend nodes. This required a new protocol for communication between nodes, a DVFS management scheme to reduce power consumption and thread management and scheduling schemes which ensure that transcoding deadlines are met. Power measurements show that this approach can reduce system-wide energy consumption by 17% to 31%, compared with the Linux Ondemand governor. ACM Reference Format:Minseok Song, Yeongju Lee, and Jinhan Park. 2015. Scheduling a video transcoding server to save energy.

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“…That is, T es is initially set to the minimum common divisor of the periods of those tasks in τ (line 1). Once a valid value for C es is found, the algorithm tries to reduce the period (lines [14][15][16][17][18][19][20][21][22]. Clearly, this simple strategy does not aim at finding the optimal parameters for τ es .…”

Section: Static-slack Edf (Ss-edf)mentioning

confidence: 99%

“…Indeed, due to increasingly CMOS miniaturization, static power dissipation has exponentially increased. Due to this reason, DPM may be more effective than techniques based on Dynamic Voltage and Frequency Scaling (DVFS) [4], which aims at adjusting the frequency/power of the processor in function of the system needs e.g., [18,10]. That is, DVFS focuses on reducing dynamic energy dissipation, which is associated with transistor internal processor current.…”

Section: Introductionmentioning

confidence: 99%

Scheduling and energy savings for small scale embedded FreeRTOS-based real-time systems

Oliveira

¹

,

Lima

²

2023

Des Autom Embed Syst

2

0

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Evaluating the effectiveness of system scheduling and energy savings in embedded real-time systems with low computing resources is the problem addressed in this paper. In such systems, the characteristics of the implemented scheduling policy play a relevant role in both schedulability and energy consumption. Ideally, the scheduling policy should provide higher schedulability bounds and low runtime overheads, allowing for better usage of available slack in the schedule for energy saving purposes. Due its low overhead and simple implementation, the usual scheduling policy employed in real-time embedded systems is based on fixed priority (FPS). Under this scheme, as the priority of all system tasks are assigned at design time, a simple priority vector suffices to indicate the current ready task to run. System schedulability, however, is usually lower than that provided by dynamic priority schedulers (DPS) according to which task priorities are assigned at runtime. Managing dynamic priority queues incurs higher overheads, though. Deciding whether DPS is a possible choice for such embedded requires careful evaluation. We evaluate two implementations of Earliest-Deadline First (EDF), a classical DPS, implemented in FreeRTOS running on an ARM-M4 architecture. EDF is compared against an optimal FPS, namely Rate-Monotonic scheduling (RMS). Further, two mechanisms for energy savings are described. They differ by the manner they compute the slack available in an EDF schedule, statically (SS-EDF) or dynamically (DS-EDF). These two approaches are experimentally evaluated. Results indicate that EDF can be effectively used for energy savings.

show abstract

“…That is, T es is initially set to the minimum common divisor of the periods of those tasks in τ (line 1). Once a valid value for C es is found, the algorithm tries to reduce the period (lines [14][15][16][17][18][19][20][21][22]. Clearly, this simple strategy does not aim at finding the optimal parameters for τ es .…”

Section: Static-slack Edf (Ss-edf)mentioning

confidence: 99%

Scheduling and Energy Savings for Small Scale Embedded FreeRTOS-based Real-Time Systems

Oliveira

¹

,

Lima

²

2022

Preprint

0

View full text Add to dashboard Cite

Evaluating the effectiveness of system scheduling and energy savings in embedded real-time systems with low computing resources is the problem addressed in this paper. In such systems, the characteristics of the implemented scheduling policy play a relevant role in both schedulability and energy consumption. Ideally, the scheduling policy should provide higher schedulability bounds and low runtime overheads, allowing for better usage of available slack in the schedule for energy saving purposes. Due its low overhead and simple implementation, the usual scheduling policy employed in real-time embedded systems is based on fixed priority (FPS). Under this scheme, as the priority of all system tasks are assigned at design time, a simple priority vector suffices to indicate the current ready task to run. System schedulability, however, is usually lower than that provided by dynamic priority schedulers (DPS) according to which task priorities are assigned at runtime. Managing dynamic priority queues incurs higher overheads, though. Deciding whether DPS is a possible choice for such embedded requires careful evaluation. We evaluate two implementations of Earliest-Deadline First (EDF), a classical DPS, implemented in FreeRTOS running on an ARM-M4 architecture. EDF is compared against an optimal FPS, namely Rate-Monotonic scheduling (RMS). Further, two mechanisms for energy savings are described. They differ by the manner they compute the slack available in an EDF schedule, statically (SS-EDF) or dynamically (DS-EDF). These two approaches are experimentally evaluated. Results indicate that EDF can be effectively used for energy savings.

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Energy aware real time scheduling algorithm for mixed task set

Cited by 6 publications

References 16 publications

Scheduling a Video Transcoding Server to Save Energy

Scheduling a Video Transcoding Server to Save Energy

Scheduling and energy savings for small scale embedded FreeRTOS-based real-time systems

Scheduling and Energy Savings for Small Scale Embedded FreeRTOS-based Real-Time Systems

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