NetBSD/usr.sbin/tprof/tprof.8

.\"	$NetBSD: tprof.8,v 1.3 2011/12/09 15:26:48 yamt Exp $
.\"
.\" Copyright (c)2011 YAMAMOTO Takashi,
.\" All rights reserved.
.\"
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.\" ------------------------------------------------------------
.Dd November 26, 2011
.Dt TPROF 8
.Os
.\" ------------------------------------------------------------
.Sh NAME
.Nm tprof
.Nd record tprof profiling samples
.\" ------------------------------------------------------------
.Sh SYNOPSIS
.Nm
.Op Fl c
.Op Fl o Ar file
.Ar command ...
.\" ------------------------------------------------------------
.Sh DESCRIPTION
The
.Nm
is a sampling based profiler.
.Pp
.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.
.Bl -tag -width hogehoge
.It Fl o Ar file
Write the collected samples to the file named
.Ar file .
The default is
.Dq Pa tprof.out .
.It Fl c
Write the collected samples to the standard output.
Note that the output is a binary stream.
.El
.\" ------------------------------------------------------------
.Sh EXAMPLES
The following command profiles the system during 1 second and shows
the top-10 kernel functions which likely consumed CPU cycles.
.Bd -literal
	tprof -c sleep 1 2>/dev/null | tpfmt -skCLP | head -10
.Ed
.\" ------------------------------------------------------------
.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 HISTORY
.\"The
.\".Nm
.\"utility first appeared in
.\".Nx XXX .
.\" ------------------------------------------------------------
.Sh SEE ALSO
.Xr tpfmt 1 ,
.Xr tprof 4
.\" ------------------------------------------------------------
.Sh AUTHORS
The
.Nm
utility is written by
.An YAMAMOTO Takashi .
.\" ------------------------------------------------------------
.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.