First we examine the total impact of all these factors.
We run the benchmarks on an unprotected baseline system and a system implementing full DVMC as well as
SafetyNet BER. The benchmarks are run for all four
supported consistency models and both the directory
and snooping coherence systems. Figure 3 and Figure 4
show the running times of all benchmarks normalized to
an unprotected system implementing SC. Despite the
numerous performance hazards described, we observed
no slowdown exceeding 11%. The worst slowdowns
occur with SC, which is rarely implemented in modern systems. In all but 4 out of 40 DVMC configurations,
the overhead is limited to 6%. Because the performance
overheads are greater with the directory system and similar for TSO, PSO, and RMO, the rest of this section
focuses on a directory-based system with TSO.