.TH READPROFILE "8" "October 2011" "util-linux" "System Administration"
.SH NAME
-readprofile - read kernel profiling information
+readprofile \- read kernel profiling information
.SH SYNOPSIS
.B readprofile
-.RI [ options ]
+[options]
.SH VERSION
This manpage documents version 2.0 of the program.
.SH DESCRIPTION
The
.B readprofile
command uses the
-.B /proc/profile
+.I /proc/profile
information to print ascii data on standard output. The output is
organized in three columns: the first is the number of clock ticks,
the second is the name of the C function in the kernel where those
.TP
\fB\-m\fR, \fB\-\-mapfile\fR \fImapfile\fR
Specify a mapfile, which by default is
-.BR /usr/src/linux/System.map .
+.IR /usr/src/linux/System.map .
You should specify the map file on cmdline if your current kernel
isn't the last one you compiled, or if you keep System.map elsewhere.
If the name of the map file ends with `.gz' it is decompressed on the
On some architectures it is possible to alter the frequency at which
the kernel delivers profiling interrupts to each CPU. This option
allows you to set the frequency, as a multiplier of the system clock
-frequency, HZ. This is supported on i386-SMP (2.2 and 2.4 kernel)
-and also on sparc-SMP and sparc64-SMP (2.4 kernel). This option also
-resets the profiling buffer, and requires superuser privileges.
+frequency, HZ. Linux 2.6.16 dropped multiplier support for most systems.
+This option also resets the profiling buffer, and requires superuser
+privileges.
.TP
\fB\-p\fR, \fB\-\-profile\fR \fIpro-file\fR
Specify a different profiling buffer, which by default is
-.B /proc/profile.
+.IR /proc/profile .
Using a different pro-file is useful if you want to `freeze' the
kernel profiling at some time and read it later. The
-.B /proc/profile
+.I /proc/profile
file can be copied using `cat' or `cp'. There is no more support for
compressed profile buffers, like in
.B readprofile-1.1,
\fB\-r\fR, \fB\-\-reset\fR
Reset the profiling buffer. This can only be invoked by root,
because
-.B /proc/profile
+.I /proc/profile
is readable by everybody but writable only by the superuser.
However, you can make
.B readprofile
-setuid 0, in order to reset the buffer without gaining privileges.
+set-user-ID 0, in order to reset the buffer without gaining privileges.
.TP
\fB\-s, \fB\-\-counters\fR
Print individual counters within functions.
clock ticks and the last is the normalized load.
.TP
\fB\-V\fR, \fB\-\-version\fR
-This makes
-.B readprofile
-print its version number and exit.
+Display version information and exit.
.TP
\fB\-h\fR, \fB\-\-help\fR
-Display help and exit.
-.SH EXAMPLES
+Display help text and exit.
+.SH FILES
+.nf
+/proc/profile A binary snapshot of the profiling buffer.
+/usr/src/linux/System.map The symbol table for the kernel.
+/usr/src/linux/* The program being profiled :-)
+.fi
+.SH BUGS
+.LP
+.B readprofile
+only works with a 1.3.x or newer kernel, because
+.I /proc/profile
+changed in the step from 1.2 to 1.3
+.LP
+This program only works with ELF kernels. The change for a.out
+kernels is trivial, and left as an exercise to the a.out user.
+.LP
+To enable profiling, the kernel must be rebooted, because no
+profiling module is available, and it wouldn't be easy to build. To
+enable profiling, you can specify "profile=2" (or another number) on
+the kernel commandline. The number you specify is the two-exponent
+used as profiling step.
+.LP
+Profiling is disabled when interrupts are inhibited. This means that
+many profiling ticks happen when interrupts are re-enabled. Watch
+out for misleading information.
+.SH EXAMPLE
Browse the profiling buffer ordering by clock ticks:
.nf
- readprofile | sort -nr | less
+ readprofile | sort \-nr | less
.fi
Print the 20 most loaded procedures:
.nf
- readprofile | sort -nr +2 | head -20
+ readprofile | sort \-nr +2 | head \-20
.fi
Print only filesystem profile:
.fi
Look at all the kernel information, with ram addresses:
.nf
- readprofile -av | less
+ readprofile \-av | less
.fi
-Browse a `freezed' profile buffer for a non current kernel:
+Browse a `frozen' profile buffer for a non current kernel:
.nf
- readprofile -p ~/profile.freeze -m /zImage.map.gz
+ readprofile \-p ~/profile.freeze \-m /zImage.map.gz
.fi
Request profiling at 2kHz per CPU, and reset the profiling buffer:
.nf
- sudo readprofile -M 20
-.fi
-.SH BUGS
-.LP
-.B readprofile
-only works with an 1.3.x or newer kernel, because
-.B /proc/profile
-changed in the step from 1.2 to 1.3
-.LP
-This program only works with ELF kernels. The change for a.out
-kernels is trivial, and left as an exercise to the a.out user.
-.LP
-To enable profiling, the kernel must be rebooted, because no
-profiling module is available, and it wouldn't be easy to build. To
-enable profiling, you can specify "profile=2" (or another number) on
-the kernel commandline. The number you specify is the two-exponent
-used as profiling step.
-.LP
-Profiling is disabled when interrupts are inhibited. This means that
-many profiling ticks happen when interrupts are re-enabled. Watch
-out for misleading information.
-.SH FILES
-.nf
-/proc/profile A binary snapshot of the profiling buffer.
-/usr/src/linux/System.map The symbol table for the kernel.
-/usr/src/linux/* The program being profiled :-)
+ sudo readprofile \-M 20
.fi
.SH AVAILABILITY
The readprofile command is part of the util-linux package and is
available from
-.UR ftp://\:ftp.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
+.UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
Linux Kernel Archive
.UE .
projects / thirdparty / util-linux.git / blobdiff