Bug 68329 - No /proc/profile support without CONFIG_SMP
No /proc/profile support without CONFIG_SMP
Product: Red Hat Linux
Classification: Retired
Component: kernel (Show other bugs)
i686 Linux
medium Severity low
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Assigned To: Arjan van de Ven
Brian Brock
Depends On:
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Reported: 2002-07-09 02:34 EDT by davidsf
Modified: 2007-04-18 12:43 EDT (History)
0 users

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Last Closed: 2003-06-07 14:56:31 EDT
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Description davidsf 2002-07-09 02:34:46 EDT
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.0) Gecko/20020608

Description of problem:
It is impossible to build a kernel with data in /proc/profile without building
SMP. The culprit seems to be the patch linux-2.4.9-nmiprofiling.patch, which
removes the code without even adding a CONFIG_NMI or like.

Surely some explanation is due at the least.

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:
1. Add profile=# to your non-SMP kernel command line
2. Boot
3. cat /proc/profile
4. Spend about an hour messing with readprofile before pulling the source, then
looking at the obscure undocumented patches in the 2.4.18-3 kernel rpm.

Actual Results:  There is nothing in /proc/profile!

Expected Results:  There should be useful data there.

Additional info:

It's always disappointing to find features deleted in redhat packages, with no
Comment 1 davidsf 2002-07-13 17:44:55 EDT
Correction: it is CONFIG_X86_LOCAL_APIC, which is on by default in defconfig and
in the package.

It is still unfortunate that without this option there is no /proc/profile, but
it  is a more acceptable workaround than setting CONFIG_SMP.
Comment 2 davidsf 2002-07-14 21:51:57 EDT
Actually the nmiprofiling patch cuts profiling out of every code path but the
NMI event itself, so even enabling the local APIC is not a workaround.
Comment 3 Arjan van de Ven 2003-06-07 14:56:31 EDT
fixed in current erratum 

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