+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/
+ 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.
-clear readprofile -r
- <test>
-dump output readprofile -m /boot/System.map > captured_profile
+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
+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
+ ./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
+One time setup::
+
+ opcontrol --setup --vmlinux=/boot/vmlinux
+
+Some ``opcontrol`` commands::
-clear opcontrol --reset
-start opcontrol --start
+ clear opcontrol --reset
+ start opcontrol --start
<test>
-stop opcontrol --stop
-dump output opreport > output_file
+ 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.