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CMU-CS-01-146
Computer Science Department
School of Computer Science, Carnegie Mellon University
CMU-CS-01-146
Timing-accurate Storage Emulation
John Linwood Griffin, Jiri Schindler,
Steven W. Schlosser, Gregory R. Ganger
July 2001
CMU-CS-01-146.ps
CMU-CS-01-146.pdf
Keywords: Disk scheduling, storage systems
Timing-accurate storage emulation fills an important hole in the set
of common performance evaluation techniques for proposed storage designs:
it allows a researcher to experiment with not-yet-existing storage components
in the context of real systems executing real applications. As its name
suggests, a timing-accurate storage emulator appears to the system to
be a real storage component with service times matching a simulation model
of that component. This paper promotes timing-accurate storage emulation
by describing its unique features, demonstrating its feasibility, and
illustrating its value. A prototype, called the Memulator, is described
and shown to produce service times within 2% of those computed by its
component simulator for over 99% of requests. Two sets of measurements
enabled by the Memulator illustrate its power: (1) application performance
on a modern Linux system equipped with a MEMS-based storage device (no
such device exists at this time), and (2) application performance on a
modern Linux system equipped with a disk whose firmware has been modified
(we have no access to firmware source code).
26 pages
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