BRASS Research Group

Analysis of Quasi-Static Scheduling Techniques in a Virtualized Reconfigurable Machine

Article by Yury Markovskiy, Eylon Caspi, Randy Huang, Joseph Yeh, Michael Chu, John Wawrzynek, and André DeHon.
In Proceedings of the Tenth ACM International Symposium on Field-Programmable Gate Arrays (FPGA 2002), Monterey CA, pp. 196--205, Feb. 24--26, 2002.

Abstract: The SCORE compute model uses fixed-size, virtual compute and memory pages connected by stream links to capture the definition of a computation abstracted from the detailed size of the physical hardware. When the number of physical compute pages is smaller than the number of virtual compute pages in the abstract computation graph, the design is time-multiplexed onto the available physical hardware. A key component of this strategy is an automatic scheduler that selects the temporal sequencing of virtual resources onto the physical device. We describe a quasi-static scheduling strategy that retains the full semantic power of the dynamic SCORE flow graph while taking advantage of static scheduling techniques at program load time to hoist most of the computational work out of the inner scheduling loops. This strategy reduces online scheduling work per reconfiguration epoch by an order of magnitude. In addition, a more global perspective available from offline-scheduling improves schedule quality, resulting in a net reduction of total execution time by 46--81%.