sentences:  A command-line management interface allows these parameters to be modified, and new VCL scripts to be compiled, loaded and activated, without restarting the accelerator.In order to reduce the number of system calls in the fast path to a minimum, log data is stored in shared memory, and the task of monitoring, filtering, formatting and writing log data to disk is delegated to a separate application.While Varnish is designed to reduce contention between threads to a minimum, its authors claim that its performance will only be as good as that of the system's pthreads implementation.