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1 | .\" Copyright (C) 2006 Red Hat, Inc. All Rights Reserved. |
| 2 | .\" Written by Ivana Varekova <varekova@redhat.com> | |
| 3 | .\" | |
| 4 | .\" Permission is granted to make and distribute verbatim copies of this | |
| 5 | .\" manual provided the copyright notice and this permission notice are | |
| 6 | .\" preserved on all copies. | |
| 7 | .\" | |
| 8 | .\" Permission is granted to copy and distribute modified versions of this | |
| 9 | .\" manual under the conditions for verbatim copying, provided that the | |
| 10 | .\" entire resulting derived work is distributed under the terms of a | |
| 11 | .\" permission notice identical to this one. | |
| 12 | .\" | |
| 13 | .\" Since the Linux kernel and libraries are constantly changing, this | |
| 14 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
| 15 | .\" responsibility for errors or omissions, or for damages resulting from | |
| 16 | .\" the use of the information contained herein. The author(s) may not | |
| 17 | .\" have taken the same level of care in the production of this manual, | |
| 18 | .\" which is licensed free of charge, as they might when working | |
| 19 | .\" professionally. | |
| 20 | .\" | |
| 21 | .\" Formatted or processed versions of this manual, if unaccompanied by | |
| 22 | .\" the source, must acknowledge the copyright and authors of this work. | |
| 23 | .\" | |
| 24 | .\" | |
| 25 | .TH PERFMONCTL 2 "28 August 2006" Linux "Linux System Calls" | |
| 26 | .SH NAME | |
| 27 | perfmonctl \- interface to PMU | |
| 28 | .SH SYNOPSIS | |
| 29 | .nf | |
| 30 | .B #include <syscall.h> | |
| 31 | .B #include <perfmon.h> | |
| 32 | .sp | |
| 33 | .BI "long perfmonctl(int " fd ", int " cmd ", void *" arg ", int " narg "); | |
| 34 | .fi | |
| 35 | .SH DESCRIPTION | |
| 36 | .B perfmonctl | |
| 37 | system call provides an interface to PMU (performance monitoring unit). | |
| 38 | PMU consists of PMD (performance monitoring data) registers and | |
| 39 | PMC (performance monitoring control) registers, where are | |
| 40 | gathered the hardware statistic. | |
| 41 | ||
| 42 | .B perfmonctl | |
| 43 | will apply a function | |
| 44 | .I cmd | |
| 45 | to input arguments | |
| 46 | .I arg. | |
| 47 | The number of arguments is defined by input variable \fInarg\fR. | |
| 48 | .I fd | |
| 49 | specifies the perfmon context to operate on. | |
| 50 | ||
| 51 | The implemented commands | |
| 52 | .I cmd | |
| 53 | are: | |
| 54 | ||
| 55 | .TP | |
| 56 | .B PFM_CREATE_CONTEXT | |
| 57 | set up a context | |
| 58 | .nf | |
| 59 | .BI "perfmonctl(int " fd ", PFM_CREATE_CONTEXT , pfarg_context_t *" ctxt ", 1); | |
| 60 | .fi | |
| 61 | ||
| 62 | The | |
| 63 | .I fd | |
| 64 | parameter is ignored. A new context is created as specified in | |
| 65 | .I ctxt | |
| 66 | and its file descriptor is returned in \fIctxt->ctx_fd\fR. | |
| 67 | ||
| 68 | The file descriptor, apart from passing it to \fBperfmonctl\fR, | |
| 69 | can be used to read event notifications (type | |
| 70 | \fBpfm_msg_t\fR) using the | |
| 71 | .BR read (2) | |
| 72 | system call. | |
| 73 | Both | |
| 74 | .BR select (2) | |
| 75 | and | |
| 76 | .BR poll (2) | |
| 77 | can be used to wait for event notifications. | |
| 78 | ||
| 79 | The context can be destroyed using the | |
| 80 | .BR close (2) | |
| 81 | system call. | |
| 82 | .TP | |
| 83 | .B PFM_WRITE_PMCS | |
| 84 | set PMC registers | |
| 85 | .nf | |
| 86 | .BI "perfmonctl(int " fd ", PFM_WRITE_PMCS , pfarg_pmc_t *" pmcs ", n); | |
| 87 | .fi | |
| 88 | .TP | |
| 89 | .B PFM_WRITE_PMDS | |
| 90 | set PMD registers | |
| 91 | .nf | |
| 92 | .BI "perfmonctl(int " fd ", PFM_WRITE_PMDS , pfarg_pmd_t *" pmds ", n); | |
| 93 | .fi | |
| 94 | .TP | |
| 95 | .B PFM_READ_PMDS | |
| 96 | read PMD registers | |
| 97 | .nf | |
| 98 | .BI "perfmonctl(int " fd ", PFM_READ_PMDS , pfarg_pmd_t *" pmds ", n); | |
| 99 | .fi | |
| 100 | .TP | |
| 101 | .B PFM_START | |
| 102 | start monitoring | |
| 103 | .nf | |
| 104 | .BI "perfmonctl(int " fd ", PFM_START , arg , 1); | |
| 105 | .BI "perfmonctl(int " fd ", PFM_START , NULL , 0); | |
| 106 | .fi | |
| 107 | .TP | |
| 108 | .B PFM_STOP | |
| 109 | stop monitoring | |
| 110 | .nf | |
| 111 | .BI "perfmonctl(int " fd ", PFM_START , NULL , 0); | |
| 112 | .fi | |
| 113 | .TP | |
| 114 | .B PFM_LOAD_CONTEXT | |
| 115 | attach the context to a thread | |
| 116 | .nf | |
| 117 | .BI "perfmonctl(int " fd ", PFM_LOAD_CONTEXT ,pfarg_load_t *" largs , 1); | |
| 118 | .fi | |
| 119 | .TP | |
| 120 | .B PFM_UNLOAD_CONTEXT | |
| 121 | detach the context from a thread | |
| 122 | .nf | |
| 123 | .BI "perfmonctl(int " fd ", PFM_UNLOAD_CONTEXT , NULL , 0); | |
| 124 | .fi | |
| 125 | .TP | |
| 126 | .B PFM_RESTART | |
| 127 | restart monitoring after receiving an overflow notification | |
| 128 | .nf | |
| 129 | .BI "perfmonctl(int " fd ", PFM_RESTART , NULL , 0); | |
| 130 | .fi | |
| 131 | .TP | |
| 132 | .B PFM_CREATE_EVTSETS | |
| 133 | create or modify event sets | |
| 134 | .nf | |
| 135 | .BI "perfmonctl(int " fd ", PFM_CREATE_EVTSETS, pfarg_setdesc_t *desc , n); | |
| 136 | .fi | |
| 137 | .TP | |
| 138 | .B PFM_DELETE_EVTSETS | |
| 139 | delete event sets | |
| 140 | .nf | |
| 141 | .BI "perfmonctl(int " fd ", PFM_DELETE_EVTSET, pfarg_setdesc_t *desc , n); | |
| 142 | .fi | |
| 143 | .TP | |
| 144 | .B PFM_GETINFO_EVTSETS | |
| 145 | get information about event sets | |
| 146 | .nf | |
| 147 | .BI "perfmonctl(int " fd ", PFM_GETINFO_EVTSETS, pfarg_setinfo_t *info, n); | |
| 148 | .fi | |
| 149 | ||
| 150 | .SH "RETURN VALUE" | |
| 151 | .B performctl | |
| 152 | returns zero when the operation is successful. | |
| 153 | On error -1 is returned and an error code is set in \fBerrno\fR. | |
| 154 | ||
| 155 | .SH AVAILABILITY | |
| 156 | This syscall is implemented only on the IA-64 architecture since kernel 2.6. | |
| 157 | ||
| 158 | .SH "SEE ALSO" | |
| 159 | .BR gprof(1), | |
| 160 | The perfmon2 interface specification |