Recording Performance Data 
Recording Performance Data
The runtime analysis consists of two parts:
In the first part, the system measures the transaction, program, or procedure, and writes the result to a performance data file. For further information, see the section
Creating Performance Data Files. You can restrict the measurement to certain objects. You can also measure up to ten external processes.In the second part, the performance data is analyzed, and the system displays the results in list form. See
Analyzing Performance Data Files.
How Does the System Measure Runtime?
The runtime analysis tool measures the CPU time required by the measurable components of a transaction, a program, or a procedure. The information is stored in a performance data file, which you can analyze either immediately or at a later date. The CPU time required to measure the runtime is subtracted from the total CPU usage.
If you measure the runtime of a program more than once, you are unlikely to get the same result on each occasion. There are various reasons why it is very difficult to obtain identical runtimes. For example, in the first measurement, the system might read data records from the table buffer on the application server, but in a second run, it may have to read them directly from the database.
Runtimes also depend on the overall system or network load (for example, the number of jobs or systems currently active in your SAP System).