s390_runtime_instr man page

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.

Return Value

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.

Conforming to

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.

See Also

syscall(2), signal(7)

Referenced By


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