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PMCSTAT(8)		  BSD System Manager's Manual		    PMCSTAT(8)

NAME
     pmcstat — performance measurement with performance monitoring hardware

SYNOPSIS
     pmcstat [-C] [-D pathname] [-E] [-F pathname] [-G pathname]
	     [-M mapfilename] [-N] [-O logfilename] [-P event-spec]
	     [-R logfilename] [-S event-spec] [-T] [-W] [-c cpu-spec] [-d]
	     [-f pluginopt] [-g] [-k kerneldir] [-m pathname] [-n rate]
	     [-o outputfile] [-p event-spec] [-q] [-r fsroot] [-s event-spec]
	     [-t process-spec] [-v] [-w secs] [-z graphdepth] [command [args]]

DESCRIPTION
     The pmcstat utility measures system performance using the facilities pro‐
     vided by hwpmc(4).

     The pmcstat utility can measure both hardware events seen by the system
     as a whole, and those seen when a specified set of processes are execut‐
     ing on the system's CPUs.	If a specific set of processes is being tar‐
     geted (for example, if the -t process-spec option is specified, or if a
     command line is specified using command), then measurement occurs till
     command exits, or till all target processes specified by the -t
     process-spec options exit, or till the pmcstat utility is interrupted by
     the user.	If a specific set of processes is not targeted for measure‐
     ment, then pmcstat will perform system-wide measurements till interrupted
     by the user.

     A given invocation of pmcstat can mix allocations of system-mode and
     process-mode PMCs, of both counting and sampling flavors.	The values of
     all counting PMCs are printed in human readable form at regular intervals
     by pmcstat.  The output of sampling PMCs may be configured to go to a log
     file for subsequent offline analysis, or, at the expense of greater over‐
     head, may be configured to be printed in text form on the fly.

     Hardware events to measure are specified to pmcstat using event specifier
     strings event-spec.  The syntax of these event specifiers is machine
     dependent and is documented in pmc(3).

     A process-mode PMC may be configured to be inheritable by the target
     process' current and future children.

OPTIONS
     The following options are available:

     -C	     Toggle between showing cumulative or incremental counts for sub‐
	     sequent counting mode PMCs specified on the command line.	The
	     default is to show incremental counts.

     -D pathname
	     Create files with per-program samples in the directory named by
	     pathname.	The default is to create these files in the current
	     directory.

     -E	     Toggle showing per-process counts at the time a tracked process
	     exits for subsequent process-mode PMCs specified on the command
	     line.  This option is useful for mapping the performance charac‐
	     teristics of a complex pipeline of processes when used in con‐
	     junction with the -d option.  The default is to not to enable
	     per-process tracking.

     -F pathname
	     Print calltree (Kcachegrind) information to file pathname.	 If
	     argument pathname is a “-” this information is sent to the output
	     file specified by the -o option.

     -G pathname
	     Print callchain information to file pathname.  If argument
	     pathname is a “-” this information is sent to the output file
	     specified by the -o option.

     -M mapfilename
	     Write the mapping between executable objects encountered in the
	     event log and the abbreviated pathnames used for gprof(1) pro‐
	     files to file mapfilename.	 If this option is not specified, map‐
	     ping information is not written.  Argument mapfilename may be a
	     “-” in which case this mapping information is sent to the output
	     file configured by the -o option.

     -N	     Toggle capturing callchain information for subsequent sampling
	     PMCs.  The default is for sampling PMCs to capture callchain
	     information.

     -O logfilename
	     Send logging output to file logfilename.  If logfilename is of
	     the form hostname:port, where hostname does not start with a ‘.’
	     or a ‘/’, then pmcstat will open a network socket to host
	     hostname on port port.

	     If the -O option is not specified and one of the logging options
	     is requested, then pmcstat will print a textual form of the
	     logged events to the configured output file.

     -P event-spec
	     Allocate a process mode sampling PMC measuring hardware events
	     specified in event-spec.

     -R logfilename
	     Perform offline analysis using sampling data in file logfilename.

     -S event-spec
	     Allocate a system mode sampling PMC measuring hardware events
	     specified in event-spec.

     -T	     Use a top like mode for sampling PMCs. The following hotkeys can
	     be used: 'c+a' switch to accumulative mode, 'c+d' switch to delta
	     mode, 'm' merge PMCs, 'n' change view, 'p' show next PMC, ' '
	     pause, 'q' quit. calltree only: 'f' cost under threshold is seen
	     as a dot.

     -W	     Toggle logging the incremental counts seen by the threads of a
	     tracked process each time they are scheduled on a CPU.  This is
	     an experimental feature intended to help analyse the dynamic be‐
	     haviour of processes in the system.  It may incur substantial
	     overhead if enabled.  The default is for this feature to be dis‐
	     abled.

     -c cpu-spec
	     Set the cpus for subsequent system mode PMCs specified on the
	     command line to cpu-spec.	Argument cpu-spec is a comma separated
	     list of CPU numbers, or the literal ‘*’ denoting all unhalted
	     CPUs.  The default is to allocate system mode PMCs on all
	     unhalted CPUs.

     -d	     Toggle between process mode PMCs measuring events for the target
	     process' current and future children or only measuring events for
	     the target process.  The default is to measure events for the
	     target process alone.

     -f pluginopt
	     Pass option string to the active plugin.
	     threshold=<float> do not display cost under specified value
	     (Top).
	     skiplink=0|1 replace node with cost under threshold by a dot
	     (Top).

     -g	     Produce profiles in a format compatible with gprof(1).  A sepa‐
	     rate profile file is generated for each executable object encoun‐
	     tered.  Profile files are placed in sub-directories named by
	     their PMC event name.

     -k kerneldir
	     Set the pathname of the kernel directory to argument kerneldir.
	     This directory specifies where pmcstat should look for the kernel
	     and its modules.  The default is /boot/kernel.

     -m pathname
	     Print the sampled PCs with the name, the start and ending
	     addresses of the function within they live.  The pathname argu‐
	     ment is mandatory and indicates where informations will be
	     stored.  If argument pathname is a “-” this information is sent
	     to the output file specified by the -o option.

     -n rate
	     Set the default sampling rate for subsequent sampling mode PMCs
	     specified on the command line.  The default is to configure PMCs
	     to sample the CPU's instruction pointer every 65536 events.

     -o outputfile
	     Send counter readings and textual representations of logged data
	     to file outputfile.  The default is to send output to stderr when
	     collecting live data and to stdout when processing a pre-existing
	     logfile.

     -p event-spec
	     Allocate a process mode counting PMC measuring hardware events
	     specified in event-spec.

     -q	     Decrease verbosity.

     -r fsroot
	     Set the top of the filesystem hierarchy under which executables
	     are located to argument fsroot.  The default is /.

     -s event-spec
	     Allocate a system mode counting PMC measuring hardware events
	     specified in event-spec.

     -t process-spec
	     Attach process mode PMCs to the processes named by argument
	     process-spec.  Argument process-spec may be a non-negative inte‐
	     ger denoting a specific process id, or a regular expression for
	     selecting processes based on their command names.

     -v	     Increase verbosity.

     -w secs
	     Print the values of all counting mode PMCs or sampling mode PMCs
	     for top mode every secs seconds.  The argument secs may be a
	     fractional value.	The default interval is 5 seconds.

     -z graphdepth
	     When printing system-wide callgraphs, limit callgraphs to the
	     depth specified by argument graphdepth.

     If command is specified, it is executed using execvp(3).

EXAMPLES
     To perform system-wide statistical sampling on an AMD Athlon CPU with
     samples taken every 32768 instruction retirals and data being sampled to
     file sample.stat, use:
	   pmcstat -O sample.stat -n 32768 -S k7-retired-instructions

     To execute firefox and measure the number of data cache misses suffered
     by it and its children every 12 seconds on an AMD Athlon, use:
	   pmcstat -d -w 12 -p k7-dc-misses firefox

     To measure instructions retired for all processes named “emacs” use:
	   pmcstat -t '^emacs$' -p instructions

     To measure instructions retired for processes named “emacs” for a period
     of 10 seconds use:
	   pmcstat -t '^emacs$' -p instructions sleep 10

     To count instruction tlb-misses on CPUs 0 and 2 on a Intel Pentium
     Pro/Pentium III SMP system use:
	   pmcstat -c 0,2 -s p6-itlb-miss

     To collect profiling information for a specific process with pid 1234
     based on instruction cache misses seen by it use:
	   pmcstat -P ic-misses -t 1234 -O /tmp/sample.out

     To perform system-wide sampling on all configured processors based on
     processor instructions retired use:
	   pmcstat -S instructions -O /tmp/sample.out
     If callgraph capture is not desired use:
	   pmcstat -N -S instructions -O /tmp/sample.out

     To send the generated event log to a remote machine use:
	   pmcstat -S instructions -O remotehost:port
     On the remote machine, the sample log can be collected using nc(1):
	   nc -l remotehost port > /tmp/sample.out

     To generate gprof(1) compatible profiles from a sample file use:
	   pmcstat -R /tmp/sample.out -g

     To print a system-wide profile with callgraphs to file foo.graph use:
	   pmcstat -R /tmp/sample.out -G foo.graph

DIAGNOSTICS
     If option -v is specified, pmcstat may issue the following diagnostic
     messages:

     #callchain/dubious-frames	The number of callchain records that had an
     “impossible” value for a return address.

     #exec handling errors  The number of exec(2) events in the log file that
     named executables that could not be analyzed.

     #exec/elf	The number of exec(2) events that named ELF executables.

     #exec/unknown  The number of exec(2) events that named executables with
     unrecognized formats.

     #samples/total  The total number of samples in the log file.

     #samples/unclaimed	 The number of samples that could not be correlated to
     a known executable object (i.e., to an executable, shared library, the
     kernel or the runtime loader).

     #samples/unknown-object  The number of samples that were associated with
     an executable with an unrecognized object format.

     The pmcstat utility exits 0 on success, and >0 if an error occurs.

COMPATIBILITY
     Due to the limitations of the gmon.out file format, gprof(1) compatible
     profiles generated by the -g option do not contain information about
     calls that cross executable boundaries.  The generated gmon.out files are
     also only meaningful for native executables.

SEE ALSO
     gprof(1), nc(1), execvp(3), pmc(3), pmclog(3), hwpmc(4), pmccontrol(8),
     sysctl(8)

HISTORY
     The pmcstat utility first appeared in FreeBSD 6.0.	 It is currently under
     development.

AUTHORS
     Joseph Koshy ⟨jkoshy@FreeBSD.org⟩

BUGS
     The pmcstat utility cannot yet analyse hwpmc(4) logs generated by non-
     native architectures.

BSD			      September 19, 2008			   BSD
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