perf, x86, Pentium4: Clear the P4_CCCR_FORCE_OVF flag
Lin Ming [Wed, 25 Aug 2010 21:06:32 +0000 (21:06 +0000)]
If on Pentium4 CPUs the FORCE_OVF flag is set then an NMI happens
on every event, which can generate a flood of NMIs. Clear it.

Reported-by: Vince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/cpu/perf_event_p4.c

index febb12c..7e578e9 100644 (file)
@@ -497,6 +497,8 @@ static int p4_hw_config(struct perf_event *event)
                event->hw.config |= event->attr.config &
                        (p4_config_pack_escr(P4_ESCR_MASK_HT) |
                         p4_config_pack_cccr(P4_CCCR_MASK_HT | P4_CCCR_RESERVED));
+
+               event->hw.config &= ~P4_CCCR_FORCE_OVF;
        }
 
        rc = x86_setup_perfctr(event);