Red Hat Bugzilla – Bug 59428
(APIC) Interrupts only on CPU0 on machine with P4 Xeon (foster)
Last modified: 2007-04-18 12:40:00 EDT
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Description of problem:
All of the interrupts are only being serviced on CPU0 only on SMP machines with
XEON P4 (foster) processors inside. Intel has changed how interrupt delivery
is handled with these processors. The old method of setting the APIC's to low-
priority does not evenly distributed the interrupts among all CPU's.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Install RH7.2 on Dell SMP box with Xeon P4 processors.
2. check /proc/interrupts
Actual Results: /proc/interrupts will show 0 interrupts on all sources for any
CPU other than CPU0.
Expected Results: interrupt handling should be spread across more than one
CPU. This is the behavior with the older Xeon processors (pre-foster)
Ingo is already aware of the issue and is working on a patch. This has been
checked on RH kernel's 2.4.3, 2.4.9, 2.4.17
Fixed for the Advanced Server kernel