417 lines
12 KiB
Groff
417 lines
12 KiB
Groff
.\" Copyright (c) 2003-2008 Joseph Koshy
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.\" Copyright (c) 2007 The FreeBSD Foundation
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" This software is provided by Joseph Koshy ``as is'' and
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.\" any express or implied warranties, including, but not limited to, the
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.\" implied warranties of merchantability and fitness for a particular purpose
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.\" are disclaimed. in no event shall Joseph Koshy be liable
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.\" for any direct, indirect, incidental, special, exemplary, or consequential
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.\" damages (including, but not limited to, procurement of substitute goods
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.\" or services; loss of use, data, or profits; or business interruption)
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.\" however caused and on any theory of liability, whether in contract, strict
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.\" liability, or tort (including negligence or otherwise) arising in any way
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.\" out of the use of this software, even if advised of the possibility of
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.\" such damage.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd September 19, 2008
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.Os
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.Dt PMCSTAT 8
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.Sh NAME
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.Nm pmcstat
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.Nd "performance measurement with performance monitoring hardware"
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.Sh SYNOPSIS
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.Nm
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.Op Fl C
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.Op Fl D Ar pathname
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.Op Fl E
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.Op Fl G Ar pathname
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.Op Fl M Ar mapfilename
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.Op Fl N
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.Op Fl O Ar logfilename
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.Op Fl P Ar event-spec
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.Op Fl R Ar logfilename
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.Op Fl S Ar event-spec
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.Op Fl W
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.Op Fl c Ar cpu-spec
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.Op Fl d
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.Op Fl g
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.Op Fl k Ar kerneldir
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.Op Fl n Ar rate
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.Op Fl o Ar outputfile
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.Op Fl p Ar event-spec
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.Op Fl q
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.Op Fl r Ar fsroot
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.Op Fl s Ar event-spec
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.Op Fl t Ar process-spec
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.Op Fl v
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.Op Fl w Ar secs
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.Op Fl z Ar graphdepth
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.Op Ar command Op Ar args
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.Sh DESCRIPTION
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The
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.Nm
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utility measures system performance using the facilities provided by
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.Xr hwpmc 4 .
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.Pp
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The
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.Nm
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utility can measure both hardware events seen by the system as a
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whole, and those seen when a specified set of processes are executing
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on the system's CPUs.
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If a specific set of processes is being targeted (for example,
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if the
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.Fl t Ar process-spec
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option is specified, or if a command line is specified using
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.Ar command ) ,
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then measurement occurs till
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.Ar command
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exits, or till all target processes specified by the
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.Fl t Ar process-spec
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options exit, or till the
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.Nm
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utility is interrupted by the user.
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If a specific set of processes is not targeted for measurement, then
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.Nm
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will perform system-wide measurements till interrupted by the
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user.
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.Pp
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A given invocation of
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.Nm
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can mix allocations of system-mode and process-mode PMCs, of both
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counting and sampling flavors.
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The values of all counting PMCs are printed in human readable form
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at regular intervals by
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.Nm .
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The output of sampling PMCs may be configured to go to a log file for
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subsequent offline analysis, or, at the expense of greater
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overhead, may be configured to be printed in text form on the fly.
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.Pp
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Hardware events to measure are specified to
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.Nm
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using event specifier strings
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.Ar event-spec .
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The syntax of these event specifiers is machine dependent and is
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documented in
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.Xr pmc 3 .
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.Pp
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A process-mode PMC may be configured to be inheritable by the target
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process' current and future children.
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.Sh OPTIONS
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The following options are available:
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.Bl -tag -width indent
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.It Fl C
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Toggle between showing cumulative or incremental counts for
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subsequent counting mode PMCs specified on the command line.
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The default is to show incremental counts.
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.It Fl D Ar pathname
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Create files with per-program samples in the directory named
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by
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.Ar pathname .
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The default is to create these files in the current directory.
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.It Fl E
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Toggle showing per-process counts at the time a tracked process
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exits for subsequent process-mode PMCs specified on the command line.
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This option is useful for mapping the performance characteristics of a
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complex pipeline of processes when used in conjunction with the
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.Fl d
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option.
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The default is to not to enable per-process tracking.
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.It Fl G Ar pathname
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Print callchain information to file
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.Ar pathname .
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If argument
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.Ar pathname
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is a
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.Dq Li -
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this information is sent to the output file specified by the
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.Fl o
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option.
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.It Fl M Ar mapfilename
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Write the mapping between executable objects encountered in the event
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log and the abbreviated pathnames used for
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.Xr gprof 1
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profiles to file
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.Ar mapfilename .
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If this option is not specified, mapping information is not written.
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Argument
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.Ar mapfilename
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may be a
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.Dq Li -
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in which case this mapping information is sent to the output
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file configured by the
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.Fl o
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option.
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.It Fl N
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Toggle capturing callchain information for subsequent sampling PMCs.
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The default is for sampling PMCs to capture callchain information.
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.It Fl O Ar logfilename
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Send logging output to file
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.Ar logfilename .
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If
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.Ar logfilename
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is of the form
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.Ar hostname Ns : Ns Ar port ,
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where
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.Ar hostname
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does not start with a
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.Ql \&.
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or a
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.Ql / ,
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then
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.Nm
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will open a network socket to host
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.Ar hostname
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on port
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.Ar port .
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.Pp
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If the
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.Fl O
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option is not specified and one of the logging options is requested,
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then
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.Nm
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will print a textual form of the logged events to the configured
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output file.
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.It Fl P Ar event-spec
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Allocate a process mode sampling PMC measuring hardware events
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specified in
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.Ar event-spec .
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.It Fl R Ar logfilename
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Perform offline analysis using sampling data in file
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.Ar logfilename .
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.It Fl S Ar event-spec
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Allocate a system mode sampling PMC measuring hardware events
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specified in
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.Ar event-spec .
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.It Fl W
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Toggle logging the incremental counts seen by the threads of a
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tracked process each time they are scheduled on a CPU.
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This is an experimental feature intended to help analyse the
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dynamic behaviour of processes in the system.
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It may incur substantial overhead if enabled.
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The default is for this feature to be disabled.
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.It Fl c Ar cpu-spec
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Set the cpus for subsequent system mode PMCs specified on the
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command line to
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.Ar cpu-spec .
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Argument
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.Ar cpu-spec
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is a comma separated list of CPU numbers, or the literal
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.Sq *
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denoting all CPUs.
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The default is to allocate system mode PMCs on all active CPUs in
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the system.
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.It Fl d
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Toggle between process mode PMCs measuring events for the target
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process' current and future children or only measuring events for
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the target process.
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The default is to measure events for the target process alone.
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.It Fl g
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Produce profiles in a format compatible with
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.Xr gprof 1 .
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A separate profile file is generated for each executable object
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encountered.
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Profile files are placed in sub-directories named by their PMC
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event name.
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.It Fl k Ar kerneldir
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Set the pathname of the kernel directory to argument
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.Ar kerneldir .
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This directory specifies where
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.Nm
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should look for the kernel and its modules.
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The default is
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.Pa /boot/kernel .
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.It Fl n Ar rate
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Set the default sampling rate for subsequent sampling mode
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PMCs specified on the command line.
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The default is to configure PMCs to sample the CPU's instruction
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pointer every 65536 events.
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.It Fl o Ar outputfile
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Send counter readings and textual representations of logged data
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to file
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.Ar outputfile .
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The default is to send output to
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.Pa stderr
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when collecting live data and to
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.Pa stdout
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when processing a pre-existing logfile.
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.It Fl p Ar event-spec
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Allocate a process mode counting PMC measuring hardware events
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specified in
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.Ar event-spec .
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.It Fl q
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Decrease verbosity.
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.It Fl r Ar fsroot
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Set the top of the filesystem hierarchy under which executables
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are located to argument
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.Ar fsroot .
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The default is
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.Pa / .
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.It Fl s Ar event-spec
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Allocate a system mode counting PMC measuring hardware events
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specified in
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.Ar event-spec .
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.It Fl t Ar process-spec
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Attach process mode PMCs to the processes named by argument
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.Ar process-spec .
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Argument
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.Ar process-spec
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may be a non-negative integer denoting a specific process id, or a
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regular expression for selecting processes based on their command names.
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.It Fl v
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Increase verbosity.
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.It Fl w Ar secs
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Print the values of all counting mode PMCs every
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.Ar secs
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seconds.
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The argument
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.Ar secs
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may be a fractional value.
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The default interval is 5 seconds.
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.It Fl z Ar graphdepth
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When printing system-wide callgraphs, limit callgraphs to the depth
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specified by argument
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.Ar graphdepth .
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.El
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.Pp
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If
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.Ar command
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is specified, it is executed using
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.Xr execvp 3 .
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.Sh EXAMPLES
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To perform system-wide statistical sampling on an AMD Athlon CPU with
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samples taken every 32768 instruction retirals and data being sampled
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to file
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.Pa sample.stat ,
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use:
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.Dl "pmcstat -O sample.stat -n 32768 -S k7-retired-instructions"
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.Pp
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To execute
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.Nm mozilla
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and measure the number of data cache misses suffered
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by it and its children every 12 seconds on an AMD Athlon, use:
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.Dl "pmcstat -d -w 12 -p k7-dc-misses mozilla"
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.Pp
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To measure instructions retired for all processes named
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.Dq emacs
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use:
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.Dl "pmcstat -t '^emacs$' -p instructions"
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.Pp
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To measure instructions retired for processes named
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.Dq emacs
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for a period of 10 seconds use:
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.Dl "pmcstat -t '^emacs$' -p instructions sleep 10"
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.Pp
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To count instruction tlb-misses on CPUs 0 and 2 on a Intel
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Pentium Pro/Pentium III SMP system use:
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.Dl "pmcstat -c 0,2 -s p6-itlb-miss"
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.Pp
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To collect profiling information for a specific process with pid 1234
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based on instruction cache misses seen by it use:
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.Dl "pmcstat -P ic-misses -t 1234 -O /tmp/sample.out"
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.Pp
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To perform system-wide sampling on all configured processors
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based on processor instructions retired use:
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.Dl "pmcstat -S instructions -O /tmp/sample.out"
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If callgraph capture is not desired use:
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.Dl "pmcstat -N -S instructions -O /tmp/sample.out"
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.Pp
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To send the generated event log to a remote machine use:
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.Dl "pmcstat -S instructions -O remotehost:port"
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On the remote machine, the sample log can be collected using
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.Xr nc 1 :
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.Dl "nc -l remotehost port > /tmp/sample.out"
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.Pp
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To generate
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.Xr gprof 1
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compatible profiles from a sample file use:
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.Dl "pmcstat -R /tmp/sample.out -g"
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.Pp
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To print a system-wide profile with callgraphs to file
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.Pa "foo.graph"
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use:
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.Dl "pmcstat -R /tmp/sample.out -G foo.graph"
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.Sh DIAGNOSTICS
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If option
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.Fl v
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is specified,
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.Nm
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may issue the following diagnostic messages:
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.Bl -diag -width indent
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.It "#callchain/dubious-frames"
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The number of callchain records that had an
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.Dq impossible
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value for a return address.
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.It "#exec handling errors"
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The number of
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.Xr exec 2
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events in the log file that named executables that could not be
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analyzed.
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.It "#exec/elf"
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The number of
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.Xr exec 2
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events that named ELF executables.
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.It "#exec/unknown"
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The number of
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.Xr exec 2
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events that named executables with unrecognized formats.
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.It "#samples/total"
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The total number of samples in the log file.
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.It "#samples/unclaimed"
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The number of samples that could not be correlated to a known
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executable object (i.e., to an executable, shared library, the
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kernel or the runtime loader).
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.It "#samples/unknown-object"
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The number of samples that were associated with an executable
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with an unrecognized object format.
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.El
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.Pp
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.Ex -std
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.Sh COMPATIBILITY
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Due to the limitations of the
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.Pa gmon.out
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file format,
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.Xr gprof 1
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compatible profiles generated by the
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.Fl g
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option do not contain information about calls that cross executable
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boundaries.
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The generated
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.Pa gmon.out
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files are also only meaningful for native executables.
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.Sh SEE ALSO
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.Xr gprof 1 ,
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.Xr nc 1 ,
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.Xr execvp 3 ,
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.Xr pmc 3 ,
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.Xr pmclog 3 ,
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.Xr hwpmc 4 ,
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.Xr pmccontrol 8 ,
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.Xr sysctl 8
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.Sh HISTORY
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The
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.Nm
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utility first appeared in
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.Fx 6.0 .
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It is
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.Ud
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.Sh AUTHORS
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.An Joseph Koshy Aq jkoshy@FreeBSD.org
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.Sh BUGS
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The
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.Nm
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utility cannot yet analyse
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.Xr hwpmc 4
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logs generated by non-native architectures.
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