1.\" Copyright (c) 2005-2006 Joseph Koshy. All rights reserved. 2.\" 3.\" Redistribution and use in source and binary forms, with or without 4.\" modification, are permitted provided that the following conditions 5.\" are met: 6.\" 1. Redistributions of source code must retain the above copyright 7.\" notice, this list of conditions and the following disclaimer. 8.\" 2. Redistributions in binary form must reproduce the above copyright 9.\" notice, this list of conditions and the following disclaimer in the 10.\" documentation and/or other materials provided with the distribution. 11.\" 12.\" This software is provided by Joseph Koshy ``as is'' and 13.\" any express or implied warranties, including, but not limited to, the 14.\" implied warranties of merchantability and fitness for a particular purpose 15.\" are disclaimed. in no event shall Joseph Koshy be liable 16.\" for any direct, indirect, incidental, special, exemplary, or consequential 17.\" damages (including, but not limited to, procurement of substitute goods 18.\" or services; loss of use, data, or profits; or business interruption) 19.\" however caused and on any theory of liability, whether in contract, strict 20.\" liability, or tort (including negligence or otherwise) arising in any way 21.\" out of the use of this software, even if advised of the possibility of 22.\" such damage. 23.\" 24.\" $FreeBSD$ 25.\" 26.Dd March 26, 2006 27.Os 28.Dt PMCLOG 3 29.Sh NAME 30.Nm pmclog_open , 31.Nm pmclog_close , 32.Nm pmclog_read , 33.Nm pmclog_feed 34.Nd parse event log data generated by 35.Xr hwpmc 4 36.Sh LIBRARY 37.Lb libpmc 38.Sh SYNOPSIS 39.In pmclog.h 40.Ft "void *" 41.Fn pmclog_open "int fd" 42.Ft void 43.Fn pmclog_close "void *cookie" 44.Ft int 45.Fn pmclog_read "void *cookie" "struct pmclog_ev *ev" 46.Ft int 47.Fn pmclog_feed "void *cookie" "char *data" "int len" 48.Sh DESCRIPTION 49These functions provide a way for application programs to extract 50events from an event stream generated by 51.Xr hwpmc 4 . 52.Pp 53A new event log parser is allocated using 54.Fn pmclog_open . 55Argument 56.Fa fd 57may be a file descriptor opened for reading if the event stream is 58present in a file, or the constant 59.Dv PMCLOG_FD_NONE 60for an event stream present in memory. 61This function returns a cookie that is passed into the other functions 62in this API set. 63.Pp 64Function 65.Fn pmclog_read 66returns the next available event in the event stream associated with 67argument 68.Fa cookie . 69Argument 70.Fa ev 71points to an event descriptor that which will contain the result of a 72successfully parsed event. 73.Pp 74An event descriptor returned by 75.Fn pmclog_read 76has the following structure: 77.Bd -literal 78struct pmclog_ev { 79 enum pmclog_state pl_state; /* parser state after 'get_event()' */ 80 off_t pl_offset; /* byte offset in stream */ 81 size_t pl_count; /* count of records so far */ 82 struct timespec pl_ts; /* log entry timestamp */ 83 enum pmclog_type pl_type; /* log entry kind */ 84 union { /* log entry data */ 85 struct pmclog_ev_closelog pl_cl; 86 struct pmclog_ev_dropnotify pl_d; 87 struct pmclog_ev_initialize pl_i; 88 struct pmclog_ev_map_in pl_mi; 89 struct pmclog_ev_map_out pl_mo; 90 struct pmclog_ev_pcsample pl_s; 91 struct pmclog_ev_pmcallocate pl_a; 92 struct pmclog_ev_pmcattach pl_t; 93 struct pmclog_ev_pmcdetach pl_d; 94 struct pmclog_ev_proccsw pl_c; 95 struct pmclog_ev_procexec pl_x; 96 struct pmclog_ev_procexit pl_e; 97 struct pmclog_ev_procfork pl_f; 98 struct pmclog_ev_sysexit pl_e; 99 struct pmclog_ev_userdata pl_u; 100 } pl_u; 101}; 102.Ed 103.Pp 104The current state of the parser is recorded in 105.Va pl_state . 106This field can take on the following values: 107.Bl -tag -width ".Dv PMCLOG_REQUIRE_DATA" 108.It Dv PMCLOG_EOF 109(For file based parsers only) 110An end-of-file condition was encountered on the configured file 111descriptor. 112.It Dv PMCLOG_ERROR 113An error occurred during parsing. 114.It Dv PMCLOG_OK 115A complete event record was read into 116.Fa *ev . 117.It Dv PMCLOG_REQUIRE_DATA 118There was insufficient data in the event stream to assemble a complete 119event record. 120For memory based parsers, more data can be fed to the 121parser using function 122.Fn pmclog_feed . 123For file based parsers, function 124.Fn pmclog_read 125may be retried when data is available on the configured file 126descriptor. 127.El 128.Pp 129The rest of the event structure is valid only if field 130.Va pl_state 131contains 132.Dv PMCLOG_OK . 133Field 134.Va pl_offset 135contains the offset of the current record in the byte stream. 136Field 137.Va pl_count 138contains the serial number of this event. 139Field 140.Va pl_ts 141contains a timestamp with the system time when the event occurred. 142Field 143.Va pl_type 144denotes the kind of the event returned in argument 145.Fa *ev 146and is one of the following: 147.Bl -tag -width ".Dv PMCLOG_TYPE_PMCALLOCATE" 148.It Dv PMCLOG_TYPE_CLOSELOG 149A marker indicating a successful close of a log file. 150This record will be the last record of a log file. 151.It Dv PMCLOG_TYPE_DROPNOTIFY 152A marker indicating that 153.Xr hwpmc 4 154had to drop data due to a resource constraint. 155.It Dv PMCLOG_TYPE_INITIALIZE 156An initialization record. 157This is the first record in a log file. 158.It Dv PMCLOG_TYPE_MAP_IN 159A record describing the introduction of a mapping to an executable 160object by a 161.Xr kldload 2 162or 163.Xr mmap 2 164system call. 165.It Dv PMCLOG_TYPE_MAP_OUT 166A record describing the removal of a mapping to an executable 167object by a 168.Xr kldunload 2 169or 170.Xr munmap 2 171system call. 172.It Dv PMCLOG_TYPE_PCSAMPLE 173A record containing an instruction pointer sample. 174.It Dv PMCLOG_TYPE_PMCALLOCATE 175A record describing a PMC allocation operation. 176.It Dv PMCLOG_TYPE_PMCATTACH 177A record describing a PMC attach operation. 178.It Dv PMCLOG_TYPE_PMCDETACH 179A record describing a PMC detach operation. 180.It Dv PMCLOG_TYPE_PROCCSW 181A record describing a PMC reading at the time of a process context switch. 182.It Dv PMCLOG_TYPE_PROCEXEC 183A record describing an 184.Xr execve 2 185by a target process. 186.It Dv PMCLOG_TYPE_PROCEXIT 187A record describing the accumulated PMC reading for a process at the 188time of 189.Xr _exit 2 . 190.It Dv PMCLOG_TYPE_PROCFORK 191A record describing a 192.Xr fork 2 193by a target process. 194.It Dv PMCLOG_TYPE_SYSEXIT 195A record describing a process exit, sent to processes 196owning system-wide sampling PMCs. 197.It Dv PMCLOG_TYPE_USERDATA 198A record containing user data. 199.El 200.Pp 201Function 202.Fn pmclog_feed 203is used with parsers configured to parse memory based event streams. 204It is intended to be called when function 205.Fn pmclog_read 206indicates the need for more data by a returning 207.Dv PMCLOG_REQUIRE_DATA 208in field 209.Va pl_state 210of its event structure argument. 211Argument 212.Fa data 213points to the start of a memory buffer containing fresh event data. 214Argument 215.Fa len 216indicates the number of data bytes available. 217The memory range 218.Bq Fa data , Fa data No + Fa len 219must remain valid till the next time 220.Fn pmclog_read 221returns an error. 222It is an error to use 223.Fn pmclog_feed 224on a parser configured to parse file data. 225.Pp 226Function 227.Fn pmclog_close 228releases the internal state allocated by a prior call 229to 230.Fn pmclog_open . 231.Sh RETURN VALUES 232Function 233.Fn pmclog_open 234will return a 235.No non- Ns Dv NULL 236value if successful or 237.Dv NULL 238otherwise. 239.Pp 240Function 241.Fn pmclog_read 242will return 0 in case a complete event record was successfully read, 243or will return \-1 and will set the 244.Va pl_state 245field of the event record to the appropriate code in case of an error. 246.Pp 247Function 248.Fn pmclog_feed 249will return 0 on success or \-1 in case of failure. 250.Sh EXAMPLES 251A template for using the log file parsing API is shown below in pseudocode: 252.Bd -literal 253void *parser; /* cookie */ 254struct pmclog_ev ev; /* parsed event */ 255int fd; /* file descriptor */ 256 257fd = open(filename, O_RDONLY); /* open log file */ 258parser = pmclog_open(fd); /* initialize parser */ 259if (parser == NULL) 260 --handle an out of memory error--; 261 262/* read and parse data */ 263while (pmclog_read(parser, &ev) == 0) { 264 assert(ev.pl_state == PMCLOG_OK); 265 /* process the event */ 266 switch (ev.pl_type) { 267 case PMCLOG_TYPE_ALLOCATE: 268 --process a pmc allocation record-- 269 break; 270 case PMCLOG_TYPE_PROCCSW: 271 --process a thread context switch record-- 272 break; 273 case PMCLOG_TYPE_PCSAMPLE: 274 --process a PC sample-- 275 break; 276 --and so on-- 277 } 278} 279 280/* examine parser state */ 281switch (ev.pl_state) { 282case PMCLOG_EOF: 283 --normal termination-- 284 break; 285case PMCLOG_ERROR: 286 --look at errno here-- 287 break; 288case PMCLOG_REQUIRE_DATA: 289 --arrange for more data to be available for parsing-- 290 break; 291default: 292 assert(0); 293 /*NOTREACHED*/ 294} 295 296pmclog_close(parser); /* cleanup */ 297.Ed 298.Sh ERRORS 299A call to 300.Fn pmclog_init_parser 301may fail with any of the errors returned by 302.Xr malloc 3 . 303.Pp 304A call to 305.Fn pmclog_read 306for a file based parser may fail with any of the errors returned by 307.Xr read 2 . 308.Sh SEE ALSO 309.Xr read 2 , 310.Xr malloc 3 , 311.Xr pmc 3 , 312.Xr hwpmc 4 , 313.Xr pmcstat 8 314.Sh HISTORY 315The 316.Nm pmclog 317API 318.Ud 319It first appeared in 320.Fx 6.0 . 321