lottery-scheduling - Lottery Scheduling: Flexible...

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Lottery Scheduling: Flexible Proportional-Share Resource Management Carl A. Waldspurger William E. Weihl MIT Laboratory for Computer Science Cambridge, MA 02139 USA Abstract This paper presents lottery scheduling , a novel randomized resource allocation mechanism. Lottery scheduling provides ef- Fcient, responsive control over the relative execution rates of computations. Such control is beyond the capabilities of conven- tional schedulers, and is desirable in systems that service requests of varying importance, such as databases, media-based applica- tions, and networks. Lottery scheduling also supports modular resource management by enabling concurrent modules to insulate their resource allocation policies from one another. A currency ab- straction is introduced to ±exibly name, share, and protect resource rights. We also show that lottery scheduling can be generalized to manage many diverse resources, such as I/O bandwidth, mem- ory, and access to locks. We have implemented a prototype lottery scheduler for the Mach 3.0 microkernel, and found that it provides ±exible and responsive control over the relative execution rates of a wide range of applications. The overhead imposed by our unoptimized prototype is comparable to that of the standard Mach timesharing policy. 1 Introduction Scheduling computations in multithreaded systems is a complex, challenging problem. Scarce resources must be multiplexed to service requests of varying importance, and the policy chosen to manage this multiplexing can have an enormous impact on throughput and response time. Accu- rate control over the quality of service provided to users and applications requires support for specifying relative computation rates. Such control is desirable across a wide spectrum of systems. ²or long-running computations such as scientiFc applications and simulations, the consumption of computing resources that are shared among users and ap- plications of varying importancemust be regulated [Hel93]. ²or interactive computations such as databases and media- based applications, programmers and users need the ability E-mail: carl , weihl . World Wide Web: . The Frst author was supported in part by an AT&T USL ²ellowship and by a grant from the MIT X Con- sortium. Prof. Weihl is currently supported by DEC while on sabbatical at DEC SRC. This research was also supported by ARPA under contract N00014-94-1-0985, by grants from AT&T and IBM, and by an equipment grant from DEC. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the ofFcial policies, either expressed or implied, of the U.S. government. to rapidly focus available resources on tasks that are cur- rently important [Dui90].
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This note was uploaded on 11/02/2010 for the course CS 3224 taught by Professor Johnsterling during the Spring '10 term at NYU Poly.

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lottery-scheduling - Lottery Scheduling: Flexible...

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