A locality-based approach for coded computation

Abstract

Modern distributed computation infrastructures are often plagued by unavailabilities such as failing or slow servers. These unavailabilities adversely affect the tail latency of computation in distributed infrastructures. The simple solution of replicating computation entails significant resource overhead. Coded computation has emerged as a resource-efficient alternative, wherein multiple units of data are encoded to create parity units and the function to be computed is applied to each of these units on distinct servers. A decoder can use the available function outputs to decode the unavailable ones. Existing coded computation approaches are resource efficient only for simple variants of linear functions such as multilinear, with even the class of low degree polynomials requiring the same multiplicative overhead as replication for practically relevant straggler tolerance. In this paper, we present a new approach to model coded computation via the lens of locality of codes. We introduce a generalized notion of locality, denoted computational locality, building upon the locality of an appropriately defined code. We show that computational locality is equivalent to the required number of workers for coded computation and leverage results from the well-studied locality of codes to design coded computation schemes. We show that recent results on coded computation of multivariate polynomials can be derived using local recovering schemes for Reed-Muller codes. We present coded computation schemes for multivariate polynomials that adaptively exploit locality properties of input data-- an inadmissible technique under existing frameworks. These schemes require fewer workers than the lower bound under existing coded computation frameworks, showing that the existing multiplicative overhead on the number of servers is not fundamental for coded computation of nonlinear functions.