1 .\" Copyright (c) 2003-2008 Joseph Koshy
2 .\" Copyright (c) 2007 The FreeBSD Foundation
3 .\" All rights reserved.
5 .\" Redistribution and use in source and binary forms, with or without
6 .\" modification, are permitted provided that the following conditions
8 .\" 1. Redistributions of source code must retain the above copyright
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10 .\" 2. Redistributions in binary form must reproduce the above copyright
11 .\" notice, this list of conditions and the following disclaimer in the
12 .\" documentation and/or other materials provided with the distribution.
14 .\" This software is provided by Joseph Koshy ``as is'' and
15 .\" any express or implied warranties, including, but not limited to, the
16 .\" implied warranties of merchantability and fitness for a particular purpose
17 .\" are disclaimed. in no event shall Joseph Koshy be liable
18 .\" for any direct, indirect, incidental, special, exemplary, or consequential
19 .\" damages (including, but not limited to, procurement of substitute goods
20 .\" or services; loss of use, data, or profits; or business interruption)
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33 .Nd "performance measurement with performance monitoring hardware"
44 .Op Fl M Ar mapfilename
46 .Op Fl O Ar logfilename
47 .Op Fl P Ar event-spec
48 .Op Fl R Ar logfilename
49 .Op Fl S Ar event-spec
64 .Op Fl o Ar outputfile
65 .Op Fl p Ar event-spec
68 .Op Fl s Ar event-spec
69 .Op Fl t Ar process-spec
70 .Op Fl u Ar event-spec
73 .Op Fl z Ar graphdepth
74 .Op Ar command Op Ar args
78 utility measures system performance using the facilities provided by
83 utility can measure both hardware events seen by the system as a
84 whole, and those seen when a specified set of processes are executing
86 If a specific set of processes is being targeted (for example,
89 option is specified, or if a command line is specified using
91 then measurement occurs till
93 exits, or till all target processes specified by the
95 options exit, or till the
97 utility is interrupted by the user.
98 If a specific set of processes is not targeted for measurement, then
100 will perform system-wide measurements till interrupted by the
103 A given invocation of
105 can mix allocations of system-mode and process-mode PMCs, of both
106 counting and sampling flavors.
107 The values of all counting PMCs are printed in human readable form
108 at regular intervals by
110 The output of sampling PMCs may be configured to go to a log file for
111 subsequent offline analysis, or, at the expense of greater
112 overhead, may be configured to be printed in text form on the fly.
114 Hardware events to measure are specified to
116 using event specifier strings
118 The syntax of these event specifiers is machine dependent and is
122 A process-mode PMC may be configured to be inheritable by the target
123 process' current and future children.
125 The following options are available:
126 .Bl -tag -width indent
128 Skip symbol lookup and display address instead.
130 Toggle between showing cumulative or incremental counts for
131 subsequent counting mode PMCs specified on the command line.
132 The default is to show incremental counts.
134 Create files with per-program samples in the directory named
137 The default is to create these files in the current directory.
139 Toggle showing per-process counts at the time a tracked process
140 exits for subsequent process-mode PMCs specified on the command line.
141 This option is useful for mapping the performance characteristics of a
142 complex pipeline of processes when used in conjunction with the
145 The default is to not to enable per-process tracking.
147 Print calltree (Kcachegrind) information to file
153 this information is sent to the output file specified by the
157 Print callchain information to file
163 this information is sent to the output file specified by the
167 Show the offset of the instruction pointer into the symbol.
169 List all event names.
170 .It Fl M Ar mapfilename
171 Write the mapping between executable objects encountered in the event
172 log and the abbreviated pathnames used for
176 If this option is not specified, mapping information is not written.
181 in which case this mapping information is sent to the output
182 file configured by the
186 Toggle capturing callchain information for subsequent sampling PMCs.
187 The default is for sampling PMCs to capture callchain information.
188 .It Fl O Ar logfilename
189 Send logging output to file
194 .Ar hostname Ns : Ns Ar port ,
197 does not start with a
203 will open a network socket to host
210 option is not specified and one of the logging options is requested,
213 will print a textual form of the logged events to the configured
215 .It Fl P Ar event-spec
216 Allocate a process mode sampling PMC measuring hardware events
219 .It Fl R Ar logfilename
220 Perform offline analysis using sampling data in file
222 .It Fl S Ar event-spec
223 Allocate a system mode sampling PMC measuring hardware events
229 mode for sampling PMCs. The following hotkeys
232 .Bl -tag -compact -width "Ctrl+a" -offset 4n
234 Toggle symbol resolution
238 Switch to accumulative mode
247 threshold as a dot (calltree only)
249 Toggle showing offsets into symbols
262 Toggle capturing user-space call traces while in kernel mode.
263 The default is for sampling PMCs to capture user-space callchain information
264 while in user-space mode, and kernel callchain information while in kernel mode.
266 Toggle logging the incremental counts seen by the threads of a
267 tracked process each time they are scheduled on a CPU.
268 This is an experimental feature intended to help analyse the
269 dynamic behaviour of processes in the system.
270 It may incur substantial overhead if enabled.
271 The default is for this feature to be disabled.
273 Perform a symbol and file:line lookup for each address in each
274 callgraph and save the output to
278 that only resolves the first symbol in the graph, this resolves
279 every node in the callgraph, or prints out addresses if no
280 lookup information is available.
281 This option requires the
283 option to read in samples that were previously collected and
288 Set the cpus for subsequent system mode PMCs specified on the
293 is a comma separated list of CPU numbers, or the literal
295 denoting all available CPUs.
296 The default is to allocate system mode PMCs on all available
299 Toggle between process mode PMCs measuring events for the target
300 process' current and future children or only measuring events for
302 The default is to measure events for the target process alone.
303 (it has to be passed in the command line prior to
310 Specify that the gprof profile files will use a wide history counter.
311 These files are produced in a format compatible with
313 However, other tools that cannot fully parse a BSD-style
314 gmon header might be unable to correctly parse these files.
315 .It Fl f Ar pluginopt
316 Pass option string to the active plugin.
318 threshold=<float> do not display cost under specified value (Top).
320 skiplink=0|1 replace node with cost under threshold by a dot (Top).
322 Produce profiles in a format compatible with
324 A separate profile file is generated for each executable object
326 Profile files are placed in sub-directories named by their PMC
331 which you can get from
335 .It Fl k Ar kerneldir
336 Set the pathname of the kernel directory to argument
338 This directory specifies where
340 should look for the kernel and its modules.
341 The default is to use the path of the running kernel obtained from the
344 Modules will also be searched for in /boot/modules if not found in
347 Set system-wide performance measurement duration for
352 may be a fractional value.
354 Print the sampled PCs with the name, the start and ending addresses
355 of the function within they live.
358 argument is mandatory and indicates where the information will be stored.
363 this information is sent to the output file specified by the
366 This option requires the
368 option to read in samples that were previously collected and
373 Set the default sampling rate for subsequent sampling mode
374 PMCs specified on the command line.
375 The default is to configure PMCs to sample the CPU's instruction
376 pointer every 65536 events.
377 .It Fl o Ar outputfile
378 Send counter readings and textual representations of logged data
381 The default is to send output to
383 when collecting live data and to
385 when processing a pre-existing logfile.
386 .It Fl p Ar event-spec
387 Allocate a process mode counting PMC measuring hardware events
393 Set the top of the filesystem hierarchy under which executables
394 are located to argument
398 .It Fl s Ar event-spec
399 Allocate a system mode counting PMC measuring hardware events
402 .It Fl t Ar process-spec
403 Attach process mode PMCs to the processes named by argument
407 may be a non-negative integer denoting a specific process id, or a
408 regular expression for selecting processes based on their command names.
409 .It Fl u Ar event-spec
410 Provide short description of event.
414 Print the values of all counting mode PMCs or sampling mode PMCs
420 may be a fractional value.
421 The default interval is 5 seconds.
422 .It Fl z Ar graphdepth
423 When printing system-wide callgraphs, limit callgraphs to the depth
424 specified by argument
430 is specified, it is executed using
433 To perform system-wide statistical sampling on an AMD Athlon CPU with
434 samples taken every 32768 instruction retirals and data being sampled
438 .Dl "pmcstat -O sample.stat -n 32768 -S k7-retired-instructions"
442 and measure the number of data cache misses suffered
443 by it and its children every 12 seconds on an AMD Athlon, use:
444 .Dl "pmcstat -d -w 12 -p k7-dc-misses firefox"
446 To measure instructions retired for all processes named
449 .Dl "pmcstat -t '^emacs$' -p instructions"
451 To measure instructions retired for processes named
453 for a period of 10 seconds use:
454 .Dl "pmcstat -t '^emacs$' -p instructions sleep 10"
456 To count instruction tlb-misses on CPUs 0 and 2 on a Intel
457 Pentium Pro/Pentium III SMP system use:
458 .Dl "pmcstat -c 0,2 -s p6-itlb-miss"
460 To collect profiling information for a specific process with pid 1234
461 based on instruction cache misses seen by it use:
462 .Dl "pmcstat -P ic-misses -t 1234 -O /tmp/sample.out"
464 To perform system-wide sampling on all configured processors
465 based on processor instructions retired use:
466 .Dl "pmcstat -S instructions -O /tmp/sample.out"
467 If callgraph capture is not desired use:
468 .Dl "pmcstat -N -S instructions -O /tmp/sample.out"
470 To send the generated event log to a remote machine use:
471 .Dl "pmcstat -S instructions -O remotehost:port"
472 On the remote machine, the sample log can be collected using
474 .Dl "nc -l remotehost port > /tmp/sample.out"
478 compatible profiles from a sample file use:
479 .Dl "pmcstat -R /tmp/sample.out -g"
481 To print a system-wide profile with callgraphs to file
484 .Dl "pmcstat -R /tmp/sample.out -G foo.graph"
490 may issue the following diagnostic messages:
492 .It "#callchain/dubious-frames"
493 The number of callchain records that had an
495 value for a return address.
496 .It "#exec handling errors"
499 events in the log file that named executables that could not be
504 events that named ELF executables.
508 events that named executables with unrecognized formats.
510 The total number of samples in the log file.
511 .It "#samples/unclaimed"
512 The number of samples that could not be correlated to a known
513 executable object (i.e., to an executable, shared library, the
514 kernel or the runtime loader).
515 .It "#samples/unknown-object"
516 The number of samples that were associated with an executable
517 with an unrecognized object format.
522 Due to the limitations of the
526 compatible profiles generated by the
528 option do not contain information about calls that cross executable
532 files are also only meaningful for native executables.
545 utility first appeared in
550 .An Joseph Koshy Aq Mt jkoshy@FreeBSD.org
554 utility cannot yet analyse
556 logs generated by non-native architectures.
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