OSDI 2000 Abstract
Latency Management in Storage Systems
Rodney Van Meter, Quantum Corp., and Minxi Gao, UC Berkeley
Abstract
Storage Latency Estimation Descriptors, or SLEDs, are an API that
allow applications to understand and take advantage of the dynamic
state of a storage system. By accessing data in the file system cache
or high-speed storage first, total I/O workloads can be reduced and
performance improved. SLEDs report estimated data latency, allowing
users, system utilities, and scripts to make file access decisions
based on those retrieval time estimates. SLEDs thus can be used to
improve individual application performance, reduce system workloads,
and improve the user experience with more predictable behavior.
We have modified the Linux 2.2 kernel to support SLEDs, and several
Unix utilities and astronomical applications have been modified to use
them. As a result, execution times of the Unix utilities when data
file sizes exceed the size of the file system buffer cache have been
reduced from 50% up to more than an order of magnitude. The
astronomical applications incurred 30-50% fewer page faults and
reductions in execution time of 10-35%. Performance of applications
which use SLEDs also degrade more gracefully as data file size grows.
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