Date: Tue, 10 Dec 1996 21:29:10 GMT Server: NCSA/1.4.2 Content-type: text/html Last-modified: Wed, 05 Apr 1995 19:29:35 GMT Content-length: 1650 Evaluating predicated and speculative execution on Alpha

Evaluating predicated and speculative execution on Alpha

The group:

Project idea
Predicated execution combines the effects of performing a test and branching based on the test. Hence a branch is avoided, which increases the pipeline efficiency and eases the scheduling for superscalar execution. Speculative execution, i.e., prediction of the branch direction, will facilitate speculative execution since the program contains less branches. The exact nature of their interaction, however, is not clear at the surface. Will they have their own niches, e.g., is predicated execution mainly useful for small branches and speculative for large branches? Will their efforts overlap so that the combined speedup of the parts is less than their sum, or maybe they are orthogonal (combination equals sum) or there is synergy (combination exceeds sum)?

Click here for a detailed proposal.

In the project we ended up concentrating more on the conditional moves rather than speculative execution. Here's our report .

Here's the data we gathered.


{kapu|madani|dbc1}@cs.washington.edu
Updated 4/5/95