prf(HW)                         19 June 1992                         prf(HW)


 Name

    prf - operating system profiler

 Description

    The special file /dev/prf provides access to activity information in the
    operating system.  Writing the file loads the measurement facility with
    text addresses to be monitored.  Reading the file returns these addresses
    and a set of counters indicating activity between adjacent text
    addresses.

    The recording mechanism is driven by the system clock and samples the
    program counter at line frequency.  Samples that catch the operating sys-
    tem are matched against the stored text addresses and increment corre-
    sponding counters for later processing.

    The file /dev/prf is a pseudo-device with no associated hardware.

 File

    /dev/prf

 See also

    profiler(ADM)