In the link:
Remarks
KeQueryPerformanceCounter always returns a 64-bit integer that represents the current value of a monotonically nondecreasing counter. The counter starts incrementing from zero when the computer starts up.
To get the resolution of the timer used to accumulate the current tick count, specify a non-NULL pointer value for the PerformanceFrequency parameter. The frequency value that the routine writes to the location pointed to by this parameter is the number of ticks per second.
Here, it means that freq
variable will contain ticks per second