diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /Documentation/basic_profiling.txt |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'Documentation/basic_profiling.txt')
-rw-r--r-- | Documentation/basic_profiling.txt | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/Documentation/basic_profiling.txt b/Documentation/basic_profiling.txt new file mode 100644 index 000000000000..65e3dc2d4437 --- /dev/null +++ b/Documentation/basic_profiling.txt | |||
@@ -0,0 +1,52 @@ | |||
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 | |||