0c0a400d1d
The below patch passes samples from anonymous regions to userspace instead of just dropping them. This provides the support needed for reporting anonymous-region code samples (today: basic accumulated results; later: Java and other dynamically compiled code). As this changes the format, an upgrade to the just-released 0.9 release of the userspace tools is required. This patch is based upon an earlier one by Will Cohen <wcohen@redhat.com> Signed-off-by: John Levon <levon@movementarian.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
56 lines
1.7 KiB
Text
56 lines
1.7 KiB
Text
These instructions are deliberately very basic. If you want something clever,
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go read the real docs ;-) Please don't add more stuff, but feel free to
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correct my mistakes ;-) (mbligh@aracnet.com)
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Thanks to John Levon, Dave Hansen, et al. for help writing this.
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<test> is the thing you're trying to measure.
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Make sure you have the correct System.map / vmlinux referenced!
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It is probably easiest to use "make install" for linux and hack
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/sbin/installkernel to copy vmlinux to /boot, in addition to vmlinuz,
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config, System.map, which are usually installed by default.
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Readprofile
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-----------
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A recent readprofile command is needed for 2.6, such as found in util-linux
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2.12a, which can be downloaded from:
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http://www.kernel.org/pub/linux/utils/util-linux/
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Most distributions will ship it already.
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Add "profile=2" to the kernel command line.
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clear readprofile -r
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<test>
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dump output readprofile -m /boot/System.map > captured_profile
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Oprofile
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--------
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Get the source (see Changes for required version) from
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http://oprofile.sourceforge.net/ and add "idle=poll" to the kernel command
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line.
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Configure with CONFIG_PROFILING=y and CONFIG_OPROFILE=y & reboot on new kernel
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./configure --with-kernel-support
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make install
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For superior results, be sure to enable the local APIC. If opreport sees
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a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance
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penalty.
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One time setup:
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opcontrol --setup --vmlinux=/boot/vmlinux
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clear opcontrol --reset
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start opcontrol --start
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<test>
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stop opcontrol --stop
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dump output opreport > output_file
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To only report on the kernel, run opreport -l /boot/vmlinux > output_file
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A reset is needed to clear old statistics, which survive a reboot.
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