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.  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.

ERRORS

       EINVAL The value specified in command is not a valid command or  the  value  specified  in
              signum is not a real-time signal number.

       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.

SEE ALSO

       syscall(2), signal(7)

COLOPHON

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