| 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. |
| |
