https://github.com/torvalds/linux
Revision 9e0daff30fd7ecf698e5d20b0fa7f851e427cca5 authored by David S. Miller on 13 April 2012, 18:56:22 UTC, committed by David S. Miller on 13 April 2012, 18:56:22 UTC
The DS driver registers as a subsys_initcall() but this can be too early, in particular this risks registering before we've had a chance to allocate and setup module_kset in kernel/params.c which is performed also as a subsyts_initcall(). Register DS using device_initcall() insteal. Signed-off-by: David S. Miller <davem@davemloft.net> Cc: stable@vger.kernel.org
1 parent 4166fb6
Tip revision: 9e0daff30fd7ecf698e5d20b0fa7f851e427cca5 authored by David S. Miller on 13 April 2012, 18:56:22 UTC
sparc64: Fix bootup crash on sun4v.
sparc64: Fix bootup crash on sun4v.
Tip revision: 9e0daff
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 ...
