Commit 3bdb5971 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab
Browse files

Documentation/basic_profiling.rst: convert to ReST markup 



Convert it to ReST markup and add it to the user book:

- Add a title to the document;
- touch spaces/new lines to fix Sphinx format;
- use ``foo`` for commands;
- use quote blocks where needed;
- add it to the user book;

Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@s-opensource.com>
parent d078a815

Documentation/basic_profiling.txt

+36 −23
Original line number Diff line number Diff line 
Basic kernel profiling

======================





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 

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!

``<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.

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



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.

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



Some ``readprofile`` commands::



	clear		readprofile -r

			<test>
@@ -29,10 +39,10 @@ Oprofile 
--------



Get the source (see Changes for required version) from

http://oprofile.sourceforge.net/ and add "idle=poll" to the kernel command

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 ``CONFIG_PROFILING=y`` and ``CONFIG_OPROFILE=y`` & reboot on new kernel::



	./configure --with-kernel-support

	make install
@@ -41,16 +51,19 @@ 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:

One time setup::



			opcontrol --setup --vmlinux=/boot/vmlinux



Some ``opcontrol`` commands::



	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

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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