5 These instructions are deliberately very basic. If you want something clever,
6 go read the real docs ;-)
8 Please don't add more stuff, but feel free to
9 correct my mistakes ;-) (mbligh@aracnet.com)
11 Thanks to John Levon, Dave Hansen, et al. for help writing this.
13 ``<test>`` is the thing you're trying to measure.
14 Make sure you have the correct ``System.map`` / ``vmlinux`` referenced!
16 It is probably easiest to use ``make install`` for linux and hack
17 ``/sbin/installkernel`` to copy ``vmlinux`` to ``/boot``, in addition to
18 ``vmlinuz``, ``config``, ``System.map``, which are usually installed by default.
23 A recent ``readprofile`` command is needed for 2.6, such as found in util-linux
24 2.12a, which can be downloaded from:
26 http://www.kernel.org/pub/linux/utils/util-linux/
28 Most distributions will ship it already.
30 Add ``profile=2`` to the kernel command line.
32 Some ``readprofile`` commands::
36 dump output readprofile -m /boot/System.map > captured_profile
41 Get the source (see Changes for required version) from
42 http://oprofile.sourceforge.net/ and add ``idle=poll`` to the kernel command
45 Configure with ``CONFIG_PROFILING=y`` and ``CONFIG_OPROFILE=y`` & reboot on new kernel::
47 ./configure --with-kernel-support
50 For superior results, be sure to enable the local APIC. If opreport sees
51 a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance
56 opcontrol --setup --vmlinux=/boot/vmlinux
58 Some ``opcontrol`` commands::
60 clear opcontrol --reset
61 start opcontrol --start
64 dump output opreport > output_file
66 To only report on the kernel, run ``opreport -l /boot/vmlinux > output_file``
68 A reset is needed to clear old statistics, which survive a reboot.