Revision 6a4c24ec52128c1f57b7d2d24cf4dd13fc23f474 authored by Andrew Morton on 01 February 2007, 07:48:13 UTC, committed by Linus Torvalds on 02 February 2007, 00:22:41 UTC
Remove these recently-added warnings.  They don't tell us anythng very
interesting and Kumar says "On an embedded PPC reference system I see this
message 6 times when I've got no cards in the PCI slots."

Acked-by: Kumar Gala <galak@kernel.crashing.org>
Acked-by: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent cb7468e
Raw File
basic_profiling.txt
These instructions are deliberately very basic. If you want something clever,
go read the real docs ;-) Please don't add more stuff, but feel free to 
correct my mistakes ;-)    (mbligh@aracnet.com)
Thanks to John Levon, Dave Hansen, et al. for help writing this.

<test> is the thing you're trying to measure.
Make sure you have the correct System.map / vmlinux referenced!

It is probably easiest to use "make install" for linux and hack
/sbin/installkernel to copy vmlinux to /boot, in addition to vmlinuz,
config, System.map, which are usually installed by default.

Readprofile
-----------
A recent readprofile command is needed for 2.6, such as found in util-linux
2.12a, which can be downloaded from:

http://www.kernel.org/pub/linux/utils/util-linux/

Most distributions will ship it already.

Add "profile=2" to the kernel command line.

clear		readprofile -r
		<test>
dump output	readprofile -m /boot/System.map > captured_profile

Oprofile
--------

Get the source (see Changes for required version) from
http://oprofile.sourceforge.net/ and add "idle=poll" to the kernel command
line.

Configure with CONFIG_PROFILING=y and CONFIG_OPROFILE=y & reboot on new kernel

./configure --with-kernel-support
make install

For superior results, be sure to enable the local APIC. If opreport sees
a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance
penalty.

One time setup:
		opcontrol --setup --vmlinux=/boot/vmlinux

clear		opcontrol --reset
start		opcontrol --start
		<test>
stop		opcontrol --stop
dump output	opreport >  output_file

To only report on the kernel, run opreport -l /boot/vmlinux > output_file

A reset is needed to clear old statistics, which survive a reboot.

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