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/Documentation/basic_profiling.txt

https://bitbucket.org/evzijst/gittest
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 1These instructions are deliberately very basic. If you want something clever,
 2go read the real docs ;-) Please don't add more stuff, but feel free to 
 3correct my mistakes ;-)    (mbligh@aracnet.com)
 4Thanks to John Levon, Dave Hansen, et al. for help writing this.
 5
 6<test> is the thing you're trying to measure.
 7Make sure you have the correct System.map / vmlinux referenced!
 8
 9It is probably easiest to use "make install" for linux and hack
10/sbin/installkernel to copy vmlinux to /boot, in addition to vmlinuz,
11config, System.map, which are usually installed by default.
12
13Readprofile
14-----------
15A recent readprofile command is needed for 2.6, such as found in util-linux
162.12a, which can be downloaded from:
17
18http://www.kernel.org/pub/linux/utils/util-linux/
19
20Most distributions will ship it already.
21
22Add "profile=2" to the kernel command line.
23
24clear		readprofile -r
25		<test>
26dump output	readprofile -m /boot/System.map > captured_profile
27
28Oprofile
29--------
30Get the source (I use 0.8) from http://oprofile.sourceforge.net/
31and add "idle=poll" to the kernel command line
32Configure with CONFIG_PROFILING=y and CONFIG_OPROFILE=y & reboot on new kernel
33./configure --with-kernel-support
34make install
35
36For superior results, be sure to enable the local APIC. If opreport sees
37a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance
38penalty.
39
40One time setup:
41		opcontrol --setup --vmlinux=/boot/vmlinux
42
43clear		opcontrol --reset
44start		opcontrol --start
45		<test>
46stop		opcontrol --stop
47dump output	opreport >  output_file
48
49To only report on the kernel, run opreport /boot/vmlinux > output_file
50
51A reset is needed to clear old statistics, which survive a reboot.
52