s390_runtime_instr(2) — Linux manual page

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

S390_RUNTIME_INSTR(2)        System Calls Manual       S390_RUNTIME_INSTR(2)

NAME         top

       s390_runtime_instr - enable/disable s390 CPU run-time instrumentation

SYNOPSIS         top

       #include <asm/runtime_instr.h>

       int s390_runtime_instr(int command, int signum);

DESCRIPTION         top

       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         top

       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         top

       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         top

       This system call is available since Linux 3.7.

CONFORMING TO         top

       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         top

       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         top

       syscall(2), signal(7)

COLOPHON         top

       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/.

Linux Programmer's Manual        2020-06-09            S390_RUNTIME_INSTR(2)

Pages that refer to this page: syscalls(2)