When Amdahl Meets Young/Daly

International audienceThis paper investigates the optimal number of processors to execute a parallel job, whose speedup profile obeys Amdahl's law, on a large-scale platform subject to fail-stop and silent errors. We combine the traditional checkpointing and rollback recovery strategies with verification mechanisms to cope with both error sources. We provide an exact formula to express the execution overhead incurred by a periodic checkpointing pattern of length T and with P processors, and we give first-order approximations for the optimal values T * and P * as a function of the individual processor failure rate λind. A striking result is that P * is of the order λ −1/4 ind if the checkpointing cost grows linearly with the number of processors, and of the order λ −1/3 ind if the checkpointing cost stays bounded for any P. We conduct an extensive set of simulations to support the theoretical study. The results confirm the accuracy of first-order approximation under a wide range of parameter settings

Quand Amdahl rencontre Young/Daly

This paper investigates the optimal number of processors to execute a parallel job, whose speedup profile obeys Amdahl's law, on a large-scale platform subject to fail-stop and silent errors. We combine the traditional checkpointing and rollback recovery strategies with verification mechanisms to cope with both error sources. We provide an exact formula to express the execution overhead incurred by a periodic checkpointing pattern of length $T$ and with $P$ processors,and we give first-order approximations for the optimal values $T^{*}$ and $P^{*}$as a function of the individual processor failure rate $\lambda_{\mathrm{ind}}$. A striking result is that$P^{*}$ is of the order $\lambda_{\mathrm{ind}}^{-1/4}$ when the checkpointing cost grows linearly with thenumber of processors, andof the order $\lambda_{\mathrm{ind}}^{-1/3}$ when the checkpointing cost stays bounded for any $P$.We conduct an extensive set of simulations to support the theoretical study. The results confirm the accuracy of the first-order approximation under a wide range of parameter settings.Cet article étudie le nombre optimal de processeurs pour exécuter un travail parallèle dont le profil d'accélération obéit à la loi d'Amdahl, sur une plateforme à grande échelle exposée aux pannes et aux erreurs silencieuses. Nous combinons l'approche traditionnelle de checkpointing/recovery avec des mécanismes de vérification pour faire face aux deux types d'erreurs. Nous fournissons une formule exacte pour mesurer le surcoût du temps d'exécution induit par un motif de checkpoint périodique de longueur $T$ et avec $P$ processeurs, et nous donnons une approximation au premier ordre des valeurs optimales de $T^{*}$ et $P^{*}$ en fonction du taux d'erreur individuel d'un processeur $\lambda_{\mathrm{ind}}$Un résultat frappant est que $P^{*}$ est de l'ordre de $\lambda_{\mathrm{ind}}^{-1/4}$ quand le coût de checkpoint croît linéairement avec le nombre de processeurs, et de l'ordre de $\lambda_{\mathrm{ind}}^{-1/3}$ quand le coût de checkpoint reste borné par $P$.Nous menons une large campagne de simulations pour appuyer l'étude théorique. Les résultats confirmes la précision de l'approximation au premier ordre pour une large gamme de paramètres

Spartan Daily, April 17, 1997

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William Mitchell Opinion - Volume 18, No. 3, March, 1976

Selected Table of Contents Paying the Price Campaign \u2776 Libertarian attorney seeks White House / Edward Lief Governor Anderson on Reserve Mining / Tad Jude Trustees have concerns about the College Architects present OLP Renovation Plans Founder and teacher was crusading advocate / Duane Galles Criminal Justice Reform Act: Cure or Ill? / Richard Haack Environmental Concerns: MPIRG seeks legislative action / Betsy Parker Frederick McGhee: Minnesota\u27s First Black Attorney / Duane Galles Editorial Board Duane Galles Edward Lief; Todd Young; Roberta Keller; Louis Tiltonhttps://open.mitchellhamline.edu/the-opinion/1046/thumbnail.jp

Spartan Daily, April 16, 1985

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