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|Author:||Sounak Kar, Robin Rehrmann, Arpan Mukhopadhyay, Bastian Alt, Florin Ciucu, Heinz Koeppl, Carsten Binnig, Amr Rizk|
|Kind:||In proceedings - use for conference & workshop papers|
|Book title:||Performance Evaluation|
|Keywords:||Query batching, Mean-field limit|
|Research Area(s):||IT Architectures|
|Abstract:||We analyze a data-processing system with n clients producing jobs which are processed in batches by m parallel servers; the system throughput critically depends on the batch size and a corresponding sub-additive speedup function. In practice, throughput optimization relies on numerical searches for the optimal batch size, a process that can take up to multiple days in existing commercial systems. In this paper, we model the system in terms of a closed queueing network; a standard Markovian analysis yields the optimal throughput in $\omega\left(n^4\right)$ time. Our main contribution is a mean-field model of the system for the regime where the system size is large. We show that the mean-field model has a unique, globally attractive stationary point which can be found in closed form and which characterizes the asymptotic throughput of the system as a function of the batch size. Using this expression we find the asymptotically optimal throughput in $O(1)$ time. Numerical settings from a large commercial system reveal that this asymptotic optimum is accurate in practical finite regimes.|
|Full paper (pdf)|