Name
perfmonctl — interface to IA-64 performance monitoring unit
Synopsis
#include <syscall.h> #include <perfmon.h>
long
perfmonctl( |
int fd, |
| int cmd, | |
| void *arg, | |
int narg); |
![[Note]](../stylesheet/note.png) |
Note |
|---|---|
| There is no glibc wrapper for this system call; see NOTES. |
DESCRIPTION
The IA-64-specific perfmonctl() system call provides an
interface to the PMU (performance monitoring unit). The PMU
consists of PMD (performance monitoring data) registers and
PMC (performance monitoring control) registers, which gather
hardware statistics.
perfmonctl() applies the
operation cmd to the
input arguments specified by arg. The number of arguments is
defined by narg. The
fd argument specifies
the perfmon context to operate on.
Supported values for cmd are:
PFM_CREATE_CONTEXT-
perfmonctl(int fd,PFM_CREATE_CONTEXT,pfarg_context_t *ctxt,1);Set up a context.
The
fdparameter is ignored. A new perfmon context is created as specified inctxtand its file descriptor is returned inctxt->ctx_fd.The file descriptor can be used in subsequent calls to
perfmonctl() and can be used to read event notifications (type pfm_msg_t) using read(2). The file descriptor is pollable using select(2), poll(2), and epoll(7).The context can be destroyed by calling close(2) on the file descriptor.
PFM_WRITE_PMCS-
perfmonctl(int fd,PFM_WRITE_PMCS,pfarg_reg_t *pmcs,n);Set PMC registers.
PFM_WRITE_PMDS-
perfmonctl(int fd,PFM_WRITE_PMDS,pfarg_reg_t *pmds,n);Set PMD registers.
PFM_READ_PMDS-
perfmonctl(int fd,PFM_READ_PMDS,pfarg_reg_t *pmds,n);Read PMD registers.
PFM_START-
perfmonctl(int fd,PFM_START,NULL,0);Start monitoring.
PFM_STOP-
perfmonctl(int fd,PFM_STOP,NULL,0);Stop monitoring.
PFM_LOAD_CONTEXT-
perfmonctl(int fd,PFM_LOAD_CONTEXT,pfarg_load_t *largs,1);Attach the context to a thread.
PFM_UNLOAD_CONTEXT-
perfmonctl(int fd,PFM_UNLOAD_CONTEXT,NULL,0);Detach the context from a thread.
PFM_RESTART-
perfmonctl(int fd,PFM_RESTART,NULL,0);Restart monitoring after receiving an overflow notification.
PFM_GET_FEATURES-
perfmonctl(int fd,PFM_GET_FEATURES,pfarg_features_t *arg,1); PFM_DEBUG-
perfmonctl(int fd,PFM_DEBUG,val,0);If
valis nonzero, enable debugging mode, otherwise disable. PFM_GET_PMC_RESET_VAL-
perfmonctl(int fd,PFM_GET_PMC_RESET_VAL,pfarg_reg_t *req,n);Reset PMC registers to default values.
RETURN VALUE
perfmonctl() returns zero
when the operation is successful. On error, −1 is
returned and errno is set to
indicate the error.
NOTES
This system call was broken for many years, and ultimately removed in Linux 5.10.
Glibc does not provide a wrapper for this system call; on kernels where it exists, call it using syscall(2).
COLOPHON
This page is part of release 5.13 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/.
|
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