stat/normal_clock is a SAP Parameter attribute which is used to control clock type for kernel statistics information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
sap_clock | SAP-own high performance clock using gettimeofday | Use
operating system clock (gettimeofday)
See SAP Parameter Documentation for full SAP documentation for this profile parameter.