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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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perfmonctl(2) System Calls Manual perfmonctl(2)
perfmonctl - interface to IA-64 performance monitoring unit
#include <syscall.h>
#include <perfmon.h>
long perfmonctl(int narg;
int fd, int cmd, void arg[narg], int narg);
Note: There is no glibc wrapper for this system call; see HISTORY.
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 fd parameter is ignored. A new perfmon context is
created as specified in ctxt and its file descriptor is
returned in ctxt->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 val is 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.
perfmonctl() returns zero when the operation is successful. On
error, -1 is returned and errno is set to indicate the error.
Linux on IA-64.
Added in Linux 2.4; removed in Linux 5.10.
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).
gprof(1)
The perfmon2 interface specification
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-06-28 perfmonctl(2)
Pages that refer to this page: syscalls(2)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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