From: bert hubert <ahu@ds9a.nl> Signed-off-by: bert hubert <ahu@ds9a.nl> Signed-off-by: John Levon <levon@movementarian.org> Signed-off-by: Andrew Morton <akpm@osdl.org> --- 25-akpm/Documentation/basic_profiling.txt | 40 ++++++++++++++++-------------- 1 files changed, 22 insertions(+), 18 deletions(-) diff -puN Documentation/basic_profiling.txt~oprofile-documentation-basic_profilingtxt-updates Documentation/basic_profiling.txt --- 25/Documentation/basic_profiling.txt~oprofile-documentation-basic_profilingtxt-updates 2004-06-22 11:06:40.969078632 -0700 +++ 25-akpm/Documentation/basic_profiling.txt 2004-06-22 11:06:40.972078176 -0700 @@ -5,16 +5,19 @@ Thanks to John Levon, Dave Hansen, et al <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. + +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 ----------- -You need a fixed readprofile command for 2.5 ... either get hold of -a current version from: +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/ -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/ + +Most distributions will ship it already. Add "profile=2" to the kernel command line. @@ -24,25 +27,26 @@ dump output readprofile -m /boot/System. Oprofile -------- -get source (I use 0.5) from http://oprofile.sourceforge.net/ -add "idle=poll" to the kernel command line +Get the source (I use 0.8) 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 -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 +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 -start daemon opcontrol --start-daemon clear opcontrol --reset start opcontrol --start <test> stop opcontrol --stop -dump output oprofpp -dl -i /boot/vmlinux > output_file +dump output opreport > output_file + +To only report on the kernel, run opreport /boot/vmlinux > output_file + +A reset is needed to clear old statistics, which survive a reboot. _