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): 2.4.18-3 How reproducible: Always 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 explanation.
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.
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.
fixed in current erratum