.\"	$NetBSD: tprof.8,v 1.14.2.1 2019/10/12 14:34:45 martin Exp $
.\"
.\" Copyright (c)2011 YAMAMOTO Takashi,
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.Dd October 11, 2019
.Dt TPROF 8
.Os
.Sh NAME
.Nm tprof
.Nd record tprof profiling samples
.Sh SYNOPSIS
.Nm
.Ar op
.Op Ar arguments
.Sh DESCRIPTION
The
.Nm
tool can be used to monitor hardware events (PMCs) during the execution of
certain commands.
.Pp
The
.Nm
utility makes the kernel driver start profiling,
executes the specified command,
keeps recording samples from the kernel driver until the command finishes,
and reports statistics to the standard error.
.Pp
The
.Nm tprof
pseudo driver and a suitable backend should be loaded beforehand.
.Pp
The
.Nm
utility accepts the following options.
The first argument,
.Ar op ,
specifies the action to take.
Valid actions are:
.Bl -tag -width offline -offset indent
.It list
Display a list of performance counter events available on the system.
.It monitor Xo
.Fl e
.Ar name:option
.Op Fl o Ar outfile
.Ar command
.Xc
Monitor the execution of command
.Ar command .
.Ar name
specifies the name of the event to count; it must be taken from the list of
available events.
.Ar option
specifies the source of the event; it must be a combination of
.Ar u
(userland) and
.Ar k
(kernel).
The collected samples are written into the file
.Ar outfile
if specified.
The default is
.Dq Pa tprof.out .
.It analyze Xo
.Op Fl CkLPs
.Op Fl p Ar pid
.Ar file
.Xc
Analyze the samples produced by a previous run of
.Nm tprof ,
stored in
.Ar file ,
and generate a plain text representation of them.
.Bl -tag -width XPXpidXX -offset indent
.It Fl C
Don't distinguish CPUs.
All samples are treated as its CPU number is 0.
.It Fl k
Kernel only.
Ignore samples for userland code.
.It Fl L
Don't distinguish LWPs.
All samples are treated as its LWP ID is 0.
.It Fl P
Don't distinguish processes.
All samples are treated as its PID is 0.
.It Fl p Ar pid
Process only samples for the process with PID
.Ar pid
and ignore the rest.
.It Fl s
Per symbol.
.El
.El
.Sh EXAMPLES
The following command profiles the system during 20 seconds and writes the
samples into the file myfile.out.
.Dl # tprof monitor -e llc-misses:k -o myfile.out sleep 20
The following command displays the results of the sampling.
.Dl # tprof analyze myfile.out
.Sh SUPPORT
The following CPU models are supported:
.Bl -hyphen -compact -offset indent
.It
ARMv7
.It
ARMv8
.It
x86 AMD Family 10h
.It
x86 AMD Family 15h
.It
x86 AMD Family 17h
.It
x86 Intel Generic (all Intel CPUs)
.It
x86 Intel Skylake/Kabylake
.It
x86 Intel Silvermont/Airmont
.It
x86 Intel Goldmont
.It
x86 Intel Goldmont Plus
.El
.Sh DIAGNOSTICS
The
.Nm
utility reports the following statistics about the activities of the
.Nm tprof
pseudo driver.
.Bl -tag -width dropbuf_samples
.It sample
The number of samples collected and prepared for userland consumption.
.It overflow
The number of samples dropped because the per-CPU buffer was full.
.It buf
The number of buffers successfully prepared for userland consumption.
.It emptybuf
The number of buffers which have been dropped because they were empty.
.It dropbuf
The number of buffers dropped because the number of buffers kept in the kernel
exceeds the limit.
.It dropbuf_samples
The number of samples dropped because the buffers containing the samples
were dropped.
.El
.Sh SEE ALSO
.Xr tprof 4
.Sh AUTHORS
.An -nosplit
The
.Nm
utility was written by
.An YAMAMOTO Takashi .
It was revamped by
.An Maxime Villard
in 2018.
.Sh CAVEATS
The contents and representation of recorded samples are undocumented and
will likely be changed for future releases of
.Nx
in an incompatible way.