pClock: An Arrival Curve Based Approach for QoS
Scheduling in Shared Storage
Palo Alto, CA
|Peter J Varman
To Appear in
ACM SIGMETRICS 2007
the International Conference on Measurement and Modeling of Computer Systems
June 12-16, 2007
San Diego, CA
consolidation is becoming an attractive paradigm for data organization
because of the economies of sharing and the ease of centralized
management. However, sharing of resources is viable only if applications can be isolated from each other. This work
targets the problem of providing performance guarantees to an application irrespective of the behavior of other workloads.
requirements are represented in terms of the
average throughput, latency and maximum burst size. Most earlier schemes only do weighted
bandwidth allocation; schemes that provide control of latency either cannot handle bursts or penalize
applications for their own prior behavior, such as using spare capacity.
Our algorithm pClock is based on arrival curves that intuitively
capture the bandwidth and burst requirements of applications. We show
analytically that an application following its arrival curve never misses its deadline. We have implemented pClock both in DiskSim and as a module in the Linux kernel 2.6. Our
evaluation shows three important features of pClock:
(1) benefits over existing algorithms; (2) efficient
performance isolation and burst handling; and (3) the ability to
allocate spare capacity to either speed up some applications or to a
utility, such as backup. pClock can be efficiently implemented in a system without
Full Version is available in pdf, ps.
Slides that I used for Pizza talk presentation at Rice.
Note: these were made in a short duration of time. I will be updating this link with my sigmetrics talk slides in June.