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.\" Author: Jan Glauber <jang@linux.vnet.ibm.com>
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.TH S390_RUNTIME_INSTR 2 2012-12-17 "Linux Programmer's Manual"
.SH NAME
s390_runtime_instr \- enable/disable s390 CPU run-time instrumentation
.SH SYNOPSIS
.nf
.B #include <asm/runtime_instr.h>

.BI "int s390_runtime_instr(int " command ", int " signum ");
.fi
.SH DESCRIPTION
The
.BR s390_runtime_instr ()
system call starts or stops CPU run-time instrumentation for the
calling thread.

The
.IR command
argument controls whether run-time instrumentation is started
.RB ( S390_RUNTIME_INSTR_START ,
1) or stopped
.RB ( S390_RUNTIME_INSTR_STOP ,
2) for the calling thread.

The
.IR 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.
.SH RETURN VALUE
On success,
.BR 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
.IR errno
is set to one of the error codes listed below.
.SH ERRORS
.TP
.B EINVAL
The value specified in
.IR command
is not a valid command or the value specified in
.IR signum
is not a real-time signal number.
.TP
.B ENOMEM
Allocating memory for the run-time instrumentation control block failed.
.TP
.B EOPNOTSUPP
The run-time instrumentation facility is not available.
.SH VERSIONS
This system call is available since Linux 3.7.
.SH 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.
.SH NOTES
Glibc does not provide a wrapper for this system call, use
.BR syscall (2)
to call it.
.SH SEE ALSO
.BR syscall (2),
.BR signal (7)
.SH COLOPHON
This page is part of release 4.10 of the Linux
.I 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/.