Messages in this thread Patch in this message | | | Date | Tue, 24 Aug 2010 17:48:25 -0400 | From | Don Zickus <> | Subject | Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running perfctrs |
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On Fri, Aug 20, 2010 at 04:17:03PM +0200, Ingo Molnar wrote: > > it's not working so well, i'm getting: > > Uhhuh. NMI received for unknown reason 00 on CPU 9. > Do you have a strange power saving mode enabled? > Dazed and confused, but trying to continue > > on a nehalem box, after a perf top and perf stat run.
After applying the patch below, I ran the following commands on my nehalem box without reproducing what you are seeing. Any thing else I can run that might trigger it? (I also ran them on an amd phenom quad-core box).
I used 2.6.32-rc2 plus Robert's and 2 of PeterZ's patches.
perf top perf stat -a -e cycles -e instructions -e cache-references -e cache-misses -e branch-misses -- sleep 5 perf record -f -a -e cycles -e instructions -e cache-references -e cache-misses -e branch-misses -- sleep 5
Cheers, Don
From 198be1044fa603bc9582a5c19134fdf9a433fff0 Mon Sep 17 00:00:00 2001 From: Don Zickus <dzickus@redhat.com> Date: Tue, 24 Aug 2010 17:43:17 -0400 Subject: [PATCH] [x86] perf: rename nmi variable to avoid clash with entry point
There is already an entry point named .nmi in entry.S and that seems to clash with the per_cpu variable nmi defined in commit f3a860d8. Renaming this variable avoids the namespace collision.
Signed-off-by: Don Zickus <dzickus@redhat.com> --- arch/x86/kernel/cpu/perf_event.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index dd2fceb..2a05ea4 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -1205,7 +1205,7 @@ struct pmu_nmi_state { int handled; }; -static DEFINE_PER_CPU(struct pmu_nmi_state, nmi); +static DEFINE_PER_CPU_PAGE_ALIGNED(struct pmu_nmi_state, pmu_nmi); static int __kprobes perf_event_nmi_handler(struct notifier_block *self, @@ -1224,7 +1224,7 @@ perf_event_nmi_handler(struct notifier_block *self, break; case DIE_NMIUNKNOWN: this_nmi = percpu_read(irq_stat.__nmi_count); - if (this_nmi != __get_cpu_var(nmi).marked) + if (this_nmi != __get_cpu_var(pmu_nmi).marked) /* let the kernel handle the unknown nmi */ return NOTIFY_DONE; /* @@ -1248,8 +1248,8 @@ perf_event_nmi_handler(struct notifier_block *self, this_nmi = percpu_read(irq_stat.__nmi_count); if ((handled > 1) || /* the next nmi could be a back-to-back nmi */ - ((__get_cpu_var(nmi).marked == this_nmi) && - (__get_cpu_var(nmi).handled > 1))) { + ((__get_cpu_var(pmu_nmi).marked == this_nmi) && + (__get_cpu_var(pmu_nmi).handled > 1))) { /* * We could have two subsequent back-to-back nmis: The * first handles more than one counter, the 2nd @@ -1260,8 +1260,8 @@ perf_event_nmi_handler(struct notifier_block *self, * handling more than one counter. We will mark the * next (3rd) and then drop it if unhandled. */ - __get_cpu_var(nmi).marked = this_nmi + 1; - __get_cpu_var(nmi).handled = handled; + __get_cpu_var(pmu_nmi).marked = this_nmi + 1; + __get_cpu_var(pmu_nmi).handled = handled; } return NOTIFY_STOP; -- 1.7.2.1
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