[PATCH] 5/6 Provide basic documentation for profiling

People keep asking for this info, and Andrew asked me to put it under the
Documentation directory ... provides really simple instructions for taking
a profile so that users can report performance changes in a useful way.

Documentation/basic_profiling.txt

+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!
+IMHO it's easier to use "make install" for linux and hack /sbin/installkernel
+to copy config files, system.map, vmlinux to /boot.
+
+Readprofile
+-----------
+You need a fixed readprofile command for 2.5 ... either get hold of
+a current version from:
+http://www.kernel.org/pub/linux/utils/util-linux/
+or get readprofile binary fixed for 2.5 / akpm's 2.5 patch from 
+ftp://ftp.kernel.org/pub/linux/kernel/people/mbligh/tools/readprofile/
+
+Add "profile=2" to the kernel command line.
+
+clear		readprofile -r
+		<test>
+dump output	readprofile -m /boot/System.map > captured_profile
+
+Oprofile
+--------
+get source (I use 0.5) from http://oprofile.sourceforge.net/
+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
+
+One time setup (pick appropriate one for your CPU):
+P3		opcontrol --setup --vmlinux=/boot/vmlinux \
+		--ctr0-event=CPU_CLK_UNHALTED --ctr0-count=100000
+Athlon/x86-64	opcontrol --setup --vmlinux=/boot/vmlinux \
+		--ctr0-event=RETIRED_INSNS --ctr0-count=100000
+P4		opcontrol --setup --vmlinux=/boot/vmlinux \
+		--ctr0-event=GLOBAL_POWER_EVENTS \
+		--ctr0-unit-mask=1 --ctr0-count=100000
+
+start daemon	opcontrol --start-daemon
+clear		opcontrol --reset
+start		opcontrol --start
+		<test>
+stop		opcontrol --stop
+dump output	oprofpp -dl -i /boot/vmlinux  >  output_file
+