https://github.com/torvalds/linux
Revision 87885b700b9b697ce8601d415cb905862750c3b9 authored by Linus Torvalds on 21 November 2012, 04:50:07 UTC, committed by Linus Torvalds on 21 November 2012, 04:50:07 UTC
Pull KVM maintainership update from Avi Kivity: "After many years of maintaining KVM, I am moving on. It was a real pleasure for me to work with so many talented and dedicated hackers on this project. Replacing me will be one of those talented and dedicated hackers, Gleb, who has authored hundreds of patches in and around KVM." * git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: taking co-maintenance KVM: Retire as maintainer
Tip revision: 87885b700b9b697ce8601d415cb905862750c3b9 authored by Linus Torvalds on 21 November 2012, 04:50:07 UTC
Merge git://git.kernel.org/pub/scm/virt/kvm/kvm
Merge git://git.kernel.org/pub/scm/virt/kvm/kvm
Tip revision: 87885b7
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!
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
-----------
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/
Most distributions will ship it already.
Add "profile=2" to the kernel command line.
clear readprofile -r
<test>
dump output readprofile -m /boot/System.map > captured_profile
Oprofile
--------
Get the source (see Changes for required version) 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
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
clear opcontrol --reset
start opcontrol --start
<test>
stop opcontrol --stop
dump output opreport > output_file
To only report on the kernel, run opreport -l /boot/vmlinux > output_file
A reset is needed to clear old statistics, which survive a reboot.
Computing file changes ...
