[PATCH] add overlap function to gcov-tool

[Rong Xu <xur at google dot com>]

Hi,

This patch adds overlap functionality to gcov-tool. The overlap score
estimates the similarity of two profiles. Currently it only computes
overlap for arc counters.

The overlap score is defined as
\sum minimum (p1-counter[i] / p1-sum-all, p2-counter[i] / p2-sum-all)
where p1-counter[i] and p2-counter[2] are two matched counter from
profile1 and profiler2.
p1-sum-all and p2-sum-all are the sum-all counters in profiler1 and
profile2, repetitively.

The resulting score is a value ranging from 0.0 to 1.0 where 0.0 means
no match and 1.0 mean a perfect match.

This tool can be used in performance triaging and reducing the fdo
training set size (where similar inputs can be pruned).

Tested with spec2006 profiles.

Thanks,

-Rong

Attachment: gcov_tool_patch.txt
Description: Text document