A Status Report on Research in Transparent Informed
Patterson, R.H., Gibson, G.A., Satyanarayanan, M.
This paper focuses on extending the power of caching and prefetching to
reduce file read latencies by exploiting application level hints about
future I/O accesses. We argue that systems that disclose high-level knowledge
can transfer optimization information across module boundaries in a manner
consistent with sound software engineering principles. Such Transparent
Informed Prefetching (TIP) systems provide a technique for converting the
high throughput of new technologies such as disk arrays and log-structured
file systems into low latency for applications. Our preliminary experiments
show that even without a high-throughput I/O subsystem TIP yields reduced
execution time of up to 30% for applications obtaining data from a remote
file server and up to 13% for applications obtaining data from a single
local disk. These experiments indicate that greater performance benefits
will be available when TIP is integrated with low level resource management
policies and highly parallel I/O subsystems such as disk arrays.