System Calls/sec is the combined rate of calls to operating system service routines by all processes running on the computer. ...

System Calls/sec is the combined rate of calls to operating system service routines by all processes running on the computer. These routines perform all of the basic scheduling and synchronization of activities on the computer, and provide access to non-graphic devices, memory management, and name space management. This counter displays the difference between the values observed in the last two samples, divided by the duration of the sample interval.