This section describes experiments to study the performance overhead imposed by StackGuard. Note that StackGuard need only be used on programs that are SUID root, and such programs are not usually consumers of large amounts of CPU time. Thus it is only necessary that the overhead be sufficiently low that the privileged administrative daemons do not impose a noticeable compute load. The MemGuard and Canary variants of StackGuard impose different kinds of overhead, and so we microbenchmark them separately in Sections 4.2.1 and 4.2.2. Section 4.2.3 presents macrobenchmark performance data.