S390_RUNTIME_INSTR

Section: System Calls (2)
Updated: 2020-06-09
Page Index
 

NAME

s390_runtime_instr - enable/disable s390 CPU run-time instrumentation  

SYNOPSIS

#include <asm/runtime_instr.h>

int s390_runtime_instr(int command, int signum);
 

DESCRIPTION

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. This argument was used to specify a signal number that should be delivered to the thread if the run-time instrumentation buffer was full or if the run-time-instrumentation-halted interrupt had occurred. This feature was never used, and in Linux 4.4 support for this feature was removed; thus, in current kernels, this argument is ignored.  

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.  

ERRORS

EINVAL
The value specified in command is not a valid command.
EINVAL
The value specified in signum is not a real-time signal number. From Linux 4.4 onwards, the signum argument has no effect, so that an invalid signal number will not result in an error.
ENOMEM
Allocating memory for the run-time instrumentation control block failed.
EOPNOTSUPP
The run-time instrumentation facility is not available.
 

VERSIONS

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.  

NOTES

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.

Starting with Linux 4.4, support for signalling was removed, as was the check whether signum is a valid real-time signal. For backwards compatibility with older kernels, it is recommended to pass a valid real-time signal number in signum and install a handler for that signal.  

SEE ALSO

syscall(2), signal(7)  

COLOPHON

This page is part of release 5.07 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
VERSIONS
CONFORMING TO
NOTES
SEE ALSO
COLOPHON