3bdb5971ff
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: Mauro Carvalho Chehab <mchehab@s-opensource.com>
70 lines
1.8 KiB
Plaintext
70 lines
1.8 KiB
Plaintext
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
|
|
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.
|
|
|
|
Some ``readprofile`` commands::
|
|
|
|
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
|
|
|
|
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``
|
|
|
|
A reset is needed to clear old statistics, which survive a reboot.
|
|
|