A comparison of trace-sampling techniques for multi-megabyte caches

Abstract

The paper compares the trace-sampling techniques of set sampling and time sampling. Using the multi-billion reference traces of A. Borg et al. (1990), we apply both techniques to multi-megabyte caches, where sampling is most valuable. We evaluate whether either technique meets a 10% sampling goal: a method meets this goal if, at least 90% of the time, it estimates the trace's true misses per instruction with /spl les/10% relative error using /spl les/10% of the trace. Results for these traces and caches show that set sampling meets the 10% sampling goal, while time sampling does not. We also find that cold-start bias in time samples is most effectively reduced by the technique of D.A. Wood et al. (1991). Nevertheless, overcoming cold-start bias requires tens of millions of consecutive references.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>