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1da177e4 LT |
1 | These instructions are deliberately very basic. If you want something clever, |
2 | go read the real docs ;-) Please don't add more stuff, but feel free to | |
3 | correct my mistakes ;-) (mbligh@aracnet.com) | |
4 | Thanks to John Levon, Dave Hansen, et al. for help writing this. | |
5 | ||
6 | <test> is the thing you're trying to measure. | |
7 | Make sure you have the correct System.map / vmlinux referenced! | |
8 | ||
9 | It is probably easiest to use "make install" for linux and hack | |
10 | /sbin/installkernel to copy vmlinux to /boot, in addition to vmlinuz, | |
11 | config, System.map, which are usually installed by default. | |
12 | ||
13 | Readprofile | |
14 | ----------- | |
15 | A recent readprofile command is needed for 2.6, such as found in util-linux | |
16 | 2.12a, which can be downloaded from: | |
17 | ||
18 | http://www.kernel.org/pub/linux/utils/util-linux/ | |
19 | ||
20 | Most distributions will ship it already. | |
21 | ||
22 | Add "profile=2" to the kernel command line. | |
23 | ||
24 | clear readprofile -r | |
25 | <test> | |
26 | dump output readprofile -m /boot/System.map > captured_profile | |
27 | ||
28 | Oprofile | |
29 | -------- | |
30 | Get the source (I use 0.8) from http://oprofile.sourceforge.net/ | |
31 | and add "idle=poll" to the kernel command line | |
32 | Configure with CONFIG_PROFILING=y and CONFIG_OPROFILE=y & reboot on new kernel | |
33 | ./configure --with-kernel-support | |
34 | make install | |
35 | ||
36 | For superior results, be sure to enable the local APIC. If opreport sees | |
37 | a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance | |
38 | penalty. | |
39 | ||
40 | One time setup: | |
41 | opcontrol --setup --vmlinux=/boot/vmlinux | |
42 | ||
43 | clear opcontrol --reset | |
44 | start opcontrol --start | |
45 | <test> | |
46 | stop opcontrol --stop | |
47 | dump output opreport > output_file | |
48 | ||
49 | To only report on the kernel, run opreport /boot/vmlinux > output_file | |
50 | ||
51 | A reset is needed to clear old statistics, which survive a reboot. | |
52 |