S390_RUNTIME_INSTR(2) System Calls Manual S390_RUNTIME_INSTR(2)

s390_runtime_instr - enable/disable s390 CPU run-time instrumentation

#include <asm/runtime_instr.h>
int s390_runtime_instr(int command, int signum);

The s390_runtime_instr() system call starts or stops CPU run-time instrumentation for the calling thread.
The command argument controls whether run-time instrumentation is started (S390_RUNTIME_INSTR_START, 1) or stopped (S390_RUNTIME_INSTR_STOP, 2) for the calling thread.
The signum argument specifies the number of a real-time signal. The real-time signal is sent to the thread if the run-time instrumentation buffer is full or if the run-time-instrumentation-halted interrupt occurred.

On success, s390_runtime_instr() returns 0 and enables the thread for run-time instrumentation by assigning the thread a default run-time instrumentation control block. The caller can then read and modify the control block and start the run-time instrumentation. On error, -1 is returned and errno is set to one of the error codes listed below.

The value specified in command is not a valid command or the value specified in signum is not a real-time signal number.
Allocating memory for the run-time instrumentation control block failed.
The run-time instrumentation facility is not available.

This system call is available since Linux 3.7.

This Linux-specific system call is available only on the s390 architecture. The run-time instrumentation facility is available beginning with System z EC12.

Glibc does not provide a wrapper for this system call, use syscall(2) to call it.
The asm/runtime_instr.h header file is available since Linux 4.16.

syscall(2), signal(7)
2019-03-06 Linux Programmer's Manual