The -Xsystem.log.limit sets the maximum size of the -Xsystem.log file before log rotation is performed. The -Xsystem.log.archives sets the number of prior log files that are retained as zip files.
Fixed Marshal#construct_hash to handle edge case of extended Hash containing user-marshaled objects. See previous commit for associated spec.
MetricsData is now a single structure with different components (eg jit, gc, memory, system, etc.) and every thread has an instance of it. This is different that the previous configuration where some metrics were per thread and some were on all threads. The new structure simplifies summing and distributing metrics across code.