1. A computer implemented method for run-time instrumentation reporting, the method comprising: executing an instruction stream of a computer program in a multithreaded processing environment, the executing by a processor; determining, based on contents of an instrumentation control field in a program status word (PSW) dedicated to the computer program, that run-time instrumentation information of said executing instruction stream should be captured, wherein the contents of the PSW dedicated to the computer program persist during context switches by the processor; capturing, by the processor, the run-time instrumentation information of said executing instruction stream; based on said captured run-time instrumentation information, creating run-time instrumentation records; detecting a run-time instrumentation sample point of the executing instruction stream on the processor; and storing a reporting group in a run-time instrumentation program buffer, the storing based on the detecting a run-time instrumentation sample point, the storing comprising: determining a current address of the run-time instrumentation program buffer, the determining based on instruction accessible run-time instrumentation controls; and storing the reporting group into the run-time instrumentation program buffer based on an origin address and the current address of the run-time instrumentation program buffer, the reporting group comprising said created run-time instrumentation records.