perfmonctl(2)

1PERFMONCTL(2)              Linux Programmer's Manual             PERFMONCTL(2)
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NAME

6       perfmonctl - interface to IA-64 performance monitoring unit
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SYNOPSIS

9       #include <syscall.h>
10       #include <perfmon.h>
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12       long perfmonctl(int fd, int cmd, void *arg, int narg);
13       Note: There is no glibc wrapper for this system call; see NOTES.
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DESCRIPTION

16       The  IA-64-specific  perfmonctl()  system call provides an interface to
17       the PMU (performance monitoring unit).  The PMU consists of  PMD  (per‐
18       formance  monitoring  data)  registers  and PMC (performance monitoring
19       control) registers, which gather hardware statistics.
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21       perfmonctl() applies the operation cmd to the input arguments specified
22       by  arg.   The number of arguments is defined by narg.  The fd argument
23       specifies the perfmon context to operate on.
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25       Supported values for cmd are:
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27       PFM_CREATE_CONTEXT
28              perfmonctl(int fd, PFM_CREATE_CONTEXT, pfarg_context_t *ctxt, 1);
29              Set up a context.
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31              The fd parameter is ignored.  A new perfmon context  is  created
32              as  specified  in  ctxt  and  its file descriptor is returned in
33              ctxt->ctx_fd.
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35              The file descriptor can be used in  subsequent  calls  to  perf‐
36              monctl()  and  can  be  used  to  read event notifications (type
37              pfm_msg_t) using read(2).  The file descriptor is pollable using
38              select(2), poll(2), and epoll(7).
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40              The  context  can  be  destroyed by calling close(2) on the file
41              descriptor.
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43       PFM_WRITE_PMCS
44              perfmonctl(int fd, PFM_WRITE_PMCS, pfarg_reg_t *pmcs, n);
45              Set PMC registers.
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47       PFM_WRITE_PMDS
48              perfmonctl(int fd, PFM_WRITE_PMDS, pfarg_reg_t *pmds, n);
49              Set PMD registers.
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51       PFM_READ_PMDS
52              perfmonctl(int fd, PFM_READ_PMDS, pfarg_reg_t *pmds, n);
53              Read PMD registers.
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55       PFM_START
56              perfmonctl(int fd, PFM_START, NULL, 0);
57              Start monitoring.
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59       PFM_STOP
60              perfmonctl(int fd, PFM_STOP, NULL, 0);
61              Stop monitoring.
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63       PFM_LOAD_CONTEXT
64              perfmonctl(int fd, PFM_LOAD_CONTEXT, pfarg_load_t *largs, 1);
65              Attach the context to a thread.
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67       PFM_UNLOAD_CONTEXT
68              perfmonctl(int fd, PFM_UNLOAD_CONTEXT, NULL, 0);
69              Detach the context from a thread.
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71       PFM_RESTART
72              perfmonctl(int fd, PFM_RESTART, NULL, 0);
73              Restart monitoring after receiving an overflow notification.
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75       PFM_GET_FEATURES
76              perfmonctl(int fd, PFM_GET_FEATURES, pfarg_features_t *arg, 1);
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78       PFM_DEBUG
79              perfmonctl(int fd, PFM_DEBUG, val, 0);
80              If val is nonzero, enable debugging mode, otherwise disable.
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82       PFM_GET_PMC_RESET_VAL
83              perfmonctl(int fd, PFM_GET_PMC_RESET_VAL, pfarg_reg_t *req, n);
84              Reset PMC registers to default values.
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RETURN VALUE

87       perfmonctl() returns zero when the operation is successful.  On  error,
88       -1 is returned and errno is set to indicate the cause of the error.
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VERSIONS

91       perfmonctl() is available since Linux 2.4.
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CONFORMING TO

94       perfmonctl()  is  Linux-specific  and  is  available  only on the IA-64
95       architecture.
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NOTES

98       Glibc does not provide a wrapper for this system call;  call  it  using
99       syscall(2).
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COLOPHON

107       This  page  is  part of release 4.16 of the Linux man-pages project.  A
108       description of the project, information about reporting bugs,  and  the
109       latest     version     of     this    page,    can    be    found    at
110       https://www.kernel.org/doc/man-pages/.
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114Linux                             2017-09-15                     PERFMONCTL(2)