I notice that the TimeStamp class uses gettimeofday for *NIX systems. There are known issues with this function...e.g. it can jump ahead, or go backwards, e.g. on systems with multiple cores, or running in VMs. Also it can get changed by ntpd, daylight savings, or if the admin just manually changes the time of day. It doesn't appear that this is monotonic at all, even though the Poco doc claims it is.
So, what's the scoop?
Also, any reason clock_gettime() wasn't used for *NIX implementations? This function appears to be POSIX-compliant and addresses some of the issues that gettimeofday has.