[2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[Ralf Hildebrandt]

Running a vanilla 2.6.32 as Xen DomU, I'm getting:

[    0.000999] CPU: Physical Processor ID: 0
[    0.000999] CPU: Processor Core ID: 1
[    0.000999] Performance Events: AMD PMU driver.
[    0.000999] ------------[ cut here ]------------
[    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
[    0.000999] Modules linked in:
[    0.000999] Pid: 0, comm: swapper Not tainted 2.6.32 #3
[    0.000999] Call Trace:
[    0.000999]  [<ffffffff8102611a>] ? native_apic_write_dummy+0x30/0x3c
[    0.000999]  [<ffffffff8104c5a2>] warn_slowpath_common+0x77/0x8f
[    0.000999]  [<ffffffff8104c5c9>] warn_slowpath_null+0xf/0x11
[    0.000999]  [<ffffffff8102611a>] native_apic_write_dummy+0x30/0x3c
[    0.000999]  [<ffffffff8101bf49>] perf_events_lapic_init+0x2e/0x30
[    0.000999]  [<ffffffff818cc6fe>] init_hw_perf_events+0x300/0x39d
[    0.000999]  [<ffffffff818cc25a>] identify_boot_cpu+0x3c/0x3e
[    0.000999]  [<ffffffff818cc3da>] check_bugs+0x9/0x2d
[    0.000999]  [<ffffffff818c4cae>] start_kernel+0x37a/0x38f
[    0.000999]  [<ffffffff818c42c1>] x86_64_start_reservations+0xac/0xb0
[    0.000999]  [<ffffffff818c7b79>] xen_start_kernel+0x530/0x534
[    0.000999] ---[ end trace 4eaa2a86a8e2da22 ]---
[    0.000999] ... version:                0
[    0.000999] ... bit width:              48
[    0.000999] ... generic registers:      4
[    0.000999] ... value mask:             0000ffffffffffff
[    0.000999] ... max period:             00007fffffffffff
[    0.000999] ... fixed-purpose events:   0
[    0.000999] ... event mask:             000000000000000f
[    0.000999] SMP alternatives: switching to UP code

# uname -a
Linux fatush.arschkrebs.de 2.6.32 #3 SMP Tue Dec 8 22:09:42 CET 2009 x86_64 GNU/Linux

# cat /proc/cpuinfo 
processor	    : 0
vendor_id	    : AuthenticAMD
cpu family	    : 15
model		    : 67
model name	    : AMD Athlon(tm) 64 X2 Dual Core Processor 5600+
stepping	    : 3
cpu MHz	            : 2799.966
cache size	    : 1024 KB
fpu   		    : yes
fpu_exception	    : yes
cpuid level	    : 1
wp    		    : yes
flags		    : fpu de tsc msr pae cx8 cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt lm 3dnowext 3dnow up rep_good pni cx16 lahf_lm cmp_legacy svm extapic cr8_legacy
bogomips : 5599.93
TLB size : 1024 4K pages
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management: ts fid vid ttp tm stc

-- 
Ralf Hildebrandt
  Geschäftsbereich IT | Abteilung Netzwerk
  Charité - Universitätsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt@charite.de | http://www.charite.de
	    

Re: [2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[Cyrill Gorcunov]

On Thu, Dec 10, 2009 at 04:48:37PM +0100, Ralf Hildebrandt wrote:
> Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> 
> [    0.000999] CPU: Physical Processor ID: 0
> [    0.000999] CPU: Processor Core ID: 1
> [    0.000999] Performance Events: AMD PMU driver.
> [    0.000999] ------------[ cut here ]------------
> [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
> [    0.000999] Modules linked in:
> [    0.000999] Pid: 0, comm: swapper Not tainted 2.6.32 #3
> [    0.000999] Call Trace:
> [    0.000999]  [<ffffffff8102611a>] ? native_apic_write_dummy+0x30/0x3c
> [    0.000999]  [<ffffffff8104c5a2>] warn_slowpath_common+0x77/0x8f
> [    0.000999]  [<ffffffff8104c5c9>] warn_slowpath_null+0xf/0x11
> [    0.000999]  [<ffffffff8102611a>] native_apic_write_dummy+0x30/0x3c
> [    0.000999]  [<ffffffff8101bf49>] perf_events_lapic_init+0x2e/0x30
> [    0.000999]  [<ffffffff818cc6fe>] init_hw_perf_events+0x300/0x39d
> [    0.000999]  [<ffffffff818cc25a>] identify_boot_cpu+0x3c/0x3e
> [    0.000999]  [<ffffffff818cc3da>] check_bugs+0x9/0x2d
> [    0.000999]  [<ffffffff818c4cae>] start_kernel+0x37a/0x38f
> [    0.000999]  [<ffffffff818c42c1>] x86_64_start_reservations+0xac/0xb0
> [    0.000999]  [<ffffffff818c7b79>] xen_start_kernel+0x530/0x534
> [    0.000999] ---[ end trace 4eaa2a86a8e2da22 ]---
> [    0.000999] ... version:                0
> [    0.000999] ... bit width:              48
> [    0.000999] ... generic registers:      4
> [    0.000999] ... value mask:             0000ffffffffffff
> [    0.000999] ... max period:             00007fffffffffff
> [    0.000999] ... fixed-purpose events:   0
> [    0.000999] ... event mask:             000000000000000f
> [    0.000999] SMP alternatives: switching to UP code
> 

It seems amd_pmu_init() do not check if apic is enabled :(
Thanks for report!

	-- Cyrill

Re: [2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[Cyrill Gorcunov]

On Thu, Dec 10, 2009 at 07:13:35PM +0300, Cyrill Gorcunov wrote:
> On Thu, Dec 10, 2009 at 04:48:37PM +0100, Ralf Hildebrandt wrote:
> > Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> > 
> > [    0.000999] CPU: Physical Processor ID: 0
> > [    0.000999] CPU: Processor Core ID: 1
> > [    0.000999] Performance Events: AMD PMU driver.
> > [    0.000999] ------------[ cut here ]------------
> > [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
> > [    0.000999] Modules linked in:
...

I suppose it should be something like the patch below.
Please test/review.
---
perf_event: check if we have APIC enabled on AMD cpu

Ralf Hildebrandt reported:

|
| Running a vanilla 2.6.32 as Xen DomU, I'm getting:
|
| [    0.000999] CPU: Physical Processor ID: 0
| [    0.000999] CPU: Processor Core ID: 1
| [    0.000999] Performance Events: AMD PMU driver.
| [    0.000999] ------------[ cut here ]------------
| [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
| [    0.000999] Modules linked in:
| [    0.000999] Pid: 0, comm: swapper Not tainted 2.6.32 #3
| [    0.000999] Call Trace:
| [    0.000999]  [<ffffffff8102611a>] ? native_apic_write_dummy+0x30/0x3c
| [    0.000999]  [<ffffffff8104c5a2>] warn_slowpath_common+0x77/0x8f
| [    0.000999]  [<ffffffff8104c5c9>] warn_slowpath_null+0xf/0x11
| [    0.000999]  [<ffffffff8102611a>] native_apic_write_dummy+0x30/0x3c
| [    0.000999]  [<ffffffff8101bf49>] perf_events_lapic_init+0x2e/0x30
| [    0.000999]  [<ffffffff818cc6fe>] init_hw_perf_events+0x300/0x39d
| [    0.000999]  [<ffffffff818cc25a>] identify_boot_cpu+0x3c/0x3e
| [    0.000999]  [<ffffffff818cc3da>] check_bugs+0x9/0x2d
| [    0.000999]  [<ffffffff818c4cae>] start_kernel+0x37a/0x38f
| [    0.000999]  [<ffffffff818c42c1>] x86_64_start_reservations+0xac/0xb0
| [    0.000999]  [<ffffffff818c7b79>] xen_start_kernel+0x530/0x534
| [    0.000999] ---[ end trace 4eaa2a86a8e2da22 ]---
|

So we need to check if APIC has a proper state.

Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
 arch/x86/kernel/cpu/perf_event.c |   18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event.c
=====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6.git/arch/x86/kernel/cpu/perf_event.c
@@ -627,6 +627,16 @@ static __initconst u64 amd_hw_cache_even
  },
 };
 
+static void __init perfmon_check_apic(struct x86_pmu* pmu)
+{
+	if (cpu_has_apic)
+		return;
+
+	pmu->apic = 0;
+	pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
+	pr_info("no hardware sampling interrupt available.\n");
+}
+
 /*
  * AMD Performance Monitor K7 and later.
  */
@@ -2062,11 +2072,7 @@ static __init int p6_pmu_init(void)
 
 	x86_pmu = p6_pmu;
 
-	if (!cpu_has_apic) {
-		pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
-		pr_info("no hardware sampling interrupt available.\n");
-		x86_pmu.apic = 0;
-	}
+	perfmon_check_apic(&x86_pmu);
 
 	return 0;
 }
@@ -2156,6 +2162,8 @@ static __init int amd_pmu_init(void)
 	memcpy(hw_cache_event_ids, amd_hw_cache_event_ids,
 	       sizeof(hw_cache_event_ids));
 
+	perfmon_check_apic(&x86_pmu);
+
 	return 0;
 }
 

Re: [2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[Ingo Molnar]

* Cyrill Gorcunov <gorcunov@openvz.org> wrote:

> On Thu, Dec 10, 2009 at 07:13:35PM +0300, Cyrill Gorcunov wrote:
> > On Thu, Dec 10, 2009 at 04:48:37PM +0100, Ralf Hildebrandt wrote:
> > > Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> > > 
> > > [    0.000999] CPU: Physical Processor ID: 0
> > > [    0.000999] CPU: Processor Core ID: 1
> > > [    0.000999] Performance Events: AMD PMU driver.
> > > [    0.000999] ------------[ cut here ]------------
> > > [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
> > > [    0.000999] Modules linked in:
> ...
> 
> I suppose it should be something like the patch below.
> Please test/review.
> ---
> perf_event: check if we have APIC enabled on AMD cpu
> 
> Ralf Hildebrandt reported:
> 
> |
> | Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> |
> | [    0.000999] CPU: Physical Processor ID: 0
> | [    0.000999] CPU: Processor Core ID: 1
> | [    0.000999] Performance Events: AMD PMU driver.
> | [    0.000999] ------------[ cut here ]------------
> | [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
> | [    0.000999] Modules linked in:
> | [    0.000999] Pid: 0, comm: swapper Not tainted 2.6.32 #3
> | [    0.000999] Call Trace:
> | [    0.000999]  [<ffffffff8102611a>] ? native_apic_write_dummy+0x30/0x3c
> | [    0.000999]  [<ffffffff8104c5a2>] warn_slowpath_common+0x77/0x8f
> | [    0.000999]  [<ffffffff8104c5c9>] warn_slowpath_null+0xf/0x11
> | [    0.000999]  [<ffffffff8102611a>] native_apic_write_dummy+0x30/0x3c
> | [    0.000999]  [<ffffffff8101bf49>] perf_events_lapic_init+0x2e/0x30
> | [    0.000999]  [<ffffffff818cc6fe>] init_hw_perf_events+0x300/0x39d
> | [    0.000999]  [<ffffffff818cc25a>] identify_boot_cpu+0x3c/0x3e
> | [    0.000999]  [<ffffffff818cc3da>] check_bugs+0x9/0x2d
> | [    0.000999]  [<ffffffff818c4cae>] start_kernel+0x37a/0x38f
> | [    0.000999]  [<ffffffff818c42c1>] x86_64_start_reservations+0xac/0xb0
> | [    0.000999]  [<ffffffff818c7b79>] xen_start_kernel+0x530/0x534
> | [    0.000999] ---[ end trace 4eaa2a86a8e2da22 ]---
> |
> 
> So we need to check if APIC has a proper state.
> 
> Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> ---
>  arch/x86/kernel/cpu/perf_event.c |   18 +++++++++++++-----
>  1 file changed, 13 insertions(+), 5 deletions(-)
> 
> Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event.c
> =====================================================================
> --- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event.c
> +++ linux-2.6.git/arch/x86/kernel/cpu/perf_event.c
> @@ -627,6 +627,16 @@ static __initconst u64 amd_hw_cache_even
>   },
>  };
>  
> +static void __init perfmon_check_apic(struct x86_pmu* pmu)
> +{
> +	if (cpu_has_apic)
> +		return;
> +
> +	pmu->apic = 0;
> +	pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
> +	pr_info("no hardware sampling interrupt available.\n");
> +}
> +
>  /*
>   * AMD Performance Monitor K7 and later.
>   */
> @@ -2062,11 +2072,7 @@ static __init int p6_pmu_init(void)
>  
>  	x86_pmu = p6_pmu;
>  
> -	if (!cpu_has_apic) {
> -		pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
> -		pr_info("no hardware sampling interrupt available.\n");
> -		x86_pmu.apic = 0;
> -	}
> +	perfmon_check_apic(&x86_pmu);
>  
>  	return 0;
>  }
> @@ -2156,6 +2162,8 @@ static __init int amd_pmu_init(void)
>  	memcpy(hw_cache_event_ids, amd_hw_cache_event_ids,
>  	       sizeof(hw_cache_event_ids));
>  
> +	perfmon_check_apic(&x86_pmu);
> +
>  	return 0;
>  }

Similar check needed in intel_pmu_init() as well? Also, i'd suggest to 
name it pmu_check_apic() or so - and why call it in the middle of of the 
PMU init functions? All PMU drivers are APIC based, so this call can be 
done right after:

        if (err != 0) {
                pr_cont("no PMU driver, software events only.\n");
                return;
        }

	pmu_check_apic();

in a single place. Also, no need to pass in &x86_pmu - we have a single 
PMU driver.

Thanks,

	Ingo

Re: [2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[Cyrill Gorcunov]

On Thu, Dec 10, 2009 at 05:37:45PM +0100, Ingo Molnar wrote:
...
> >  
> > +	perfmon_check_apic(&x86_pmu);
> > +
> >  	return 0;
> >  }
> 
> Similar check needed in intel_pmu_init() as well?

Yes (though p6 model already has such a check [fixed by Peter iirc])

>
> Also, i'd suggest to 
> name it pmu_check_apic() or so - and why call it in the middle of of the 
> PMU init functions? All PMU drivers are APIC based, so this call can be 
> done right after:
> 
>         if (err != 0) {
>                 pr_cont("no PMU driver, software events only.\n");
>                 return;
>         }
> 
> 	pmu_check_apic();
> 
> in a single place. Also, no need to pass in &x86_pmu - we have a single 
> PMU driver.
> 
> Thanks,
> 
> 	Ingo
> 

OK, will update and resend. Thanks for comments!

	-- Cyrill

Re: [2.6.32] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()

[Cyrill Gorcunov]

On Thu, Dec 10, 2009 at 07:49:04PM +0300, Cyrill Gorcunov wrote:
...
> 
> OK, will update and resend. Thanks for comments!
> 
> 	-- Cyrill

Here is it, please review.

	-- Cyrill
---
x86,pmu: check if we have APIC enabled

Ralf Hildebrandt reported:

|
| Running a vanilla 2.6.32 as Xen DomU, I'm getting:
|
| [    0.000999] CPU: Physical Processor ID: 0
| [    0.000999] CPU: Processor Core ID: 1
| [    0.000999] Performance Events: AMD PMU driver.
| [    0.000999] ------------[ cut here ]------------
| [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x30/0x3c()
| [    0.000999] Modules linked in:
| [    0.000999] Pid: 0, comm: swapper Not tainted 2.6.32 #3
| [    0.000999] Call Trace:
| [    0.000999]  [<ffffffff8102611a>] ? native_apic_write_dummy+0x30/0x3c
| [    0.000999]  [<ffffffff8104c5a2>] warn_slowpath_common+0x77/0x8f
| [    0.000999]  [<ffffffff8104c5c9>] warn_slowpath_null+0xf/0x11
| [    0.000999]  [<ffffffff8102611a>] native_apic_write_dummy+0x30/0x3c
| [    0.000999]  [<ffffffff8101bf49>] perf_events_lapic_init+0x2e/0x30
| [    0.000999]  [<ffffffff818cc6fe>] init_hw_perf_events+0x300/0x39d
| [    0.000999]  [<ffffffff818cc25a>] identify_boot_cpu+0x3c/0x3e
| [    0.000999]  [<ffffffff818cc3da>] check_bugs+0x9/0x2d
| [    0.000999]  [<ffffffff818c4cae>] start_kernel+0x37a/0x38f
| [    0.000999]  [<ffffffff818c42c1>] x86_64_start_reservations+0xac/0xb0
| [    0.000999]  [<ffffffff818c7b79>] xen_start_kernel+0x530/0x534
| [    0.000999] ---[ end trace 4eaa2a86a8e2da22 ]---
|

So we need to check if APIC has a proper state (ie enabled).

Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
---
 arch/x86/kernel/cpu/perf_event.c |   18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event.c
=====================================================================
--- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6.git/arch/x86/kernel/cpu/perf_event.c
@@ -2062,12 +2062,6 @@ static __init int p6_pmu_init(void)
 
 	x86_pmu = p6_pmu;
 
-	if (!cpu_has_apic) {
-		pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
-		pr_info("no hardware sampling interrupt available.\n");
-		x86_pmu.apic = 0;
-	}
-
 	return 0;
 }
 
@@ -2159,6 +2153,16 @@ static __init int amd_pmu_init(void)
 	return 0;
 }
 
+static void __init pmu_check_apic(void)
+{
+	if (cpu_has_apic)
+		return;
+
+	x86_pmu.apic = 0;
+	pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
+	pr_info("no hardware sampling interrupt available.\n");
+}
+
 void __init init_hw_perf_events(void)
 {
 	int err;
@@ -2180,6 +2184,8 @@ void __init init_hw_perf_events(void)
 		return;
 	}
 
+	pmu_check_apic();
+
 	pr_cont("%s PMU driver.\n", x86_pmu.name);
 
 	if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) {

[tip:perf/urgent] x86, perf events: Check if we have APIC enabled

[tip-bot for Cyrill Gorcunov]

Commit-ID:  125580380f418000b1a06d9a54700f1191b6e561
Gitweb:     http://git.kernel.org/tip/125580380f418000b1a06d9a54700f1191b6e561
Author:     Cyrill Gorcunov <gorcunov@openvz.org>
AuthorDate: Thu, 10 Dec 2009 19:56:34 +0300
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Thu, 10 Dec 2009 18:00:30 +0100

x86, perf events: Check if we have APIC enabled

Ralf Hildebrandt reported this boot warning:

| Running a vanilla 2.6.32 as Xen DomU, I'm getting:
|
| [    0.000999] CPU: Physical Processor ID: 0
| [    0.000999] CPU: Processor Core ID: 1
| [    0.000999] Performance Events: AMD PMU driver.
| [    0.000999] ------------[ cut here ]------------
| [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy

So we need to check if APIC functionality is available, and
not just in the P6 driver but elsewhere as well.

Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091210165634.GF5086@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event.c |   18 ++++++++++++------
 1 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 1342f23..18f05ec 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -2066,12 +2066,6 @@ static __init int p6_pmu_init(void)
 
 	x86_pmu = p6_pmu;
 
-	if (!cpu_has_apic) {
-		pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
-		pr_info("no hardware sampling interrupt available.\n");
-		x86_pmu.apic = 0;
-	}
-
 	return 0;
 }
 
@@ -2163,6 +2157,16 @@ static __init int amd_pmu_init(void)
 	return 0;
 }
 
+static void __init pmu_check_apic(void)
+{
+	if (cpu_has_apic)
+		return;
+
+	x86_pmu.apic = 0;
+	pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
+	pr_info("no hardware sampling interrupt available.\n");
+}
+
 void __init init_hw_perf_events(void)
 {
 	int err;
@@ -2184,6 +2188,8 @@ void __init init_hw_perf_events(void)
 		return;
 	}
 
+	pmu_check_apic();
+
 	pr_cont("%s PMU driver.\n", x86_pmu.name);
 
 	if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) {

Re: [tip:perf/urgent] x86, perf events: Check if we have APIC enabled

[Cyrill Gorcunov]

On Thu, Dec 10, 2009 at 05:18:32PM +0000, tip-bot for Cyrill Gorcunov wrote:
> Commit-ID:  125580380f418000b1a06d9a54700f1191b6e561
> Gitweb:     http://git.kernel.org/tip/125580380f418000b1a06d9a54700f1191b6e561
> Author:     Cyrill Gorcunov <gorcunov@openvz.org>
> AuthorDate: Thu, 10 Dec 2009 19:56:34 +0300
> Committer:  Ingo Molnar <mingo@elte.hu>
> CommitDate: Thu, 10 Dec 2009 18:00:30 +0100
> 
> x86, perf events: Check if we have APIC enabled
> 
> Ralf Hildebrandt reported this boot warning:
> 
> | Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> |
> | [    0.000999] CPU: Physical Processor ID: 0
> | [    0.000999] CPU: Processor Core ID: 1
> | [    0.000999] Performance Events: AMD PMU driver.
> | [    0.000999] ------------[ cut here ]------------
> | [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy
> 
> So we need to check if APIC functionality is available, and
> not just in the P6 driver but elsewhere as well.
> 
> Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> LKML-Reference: <20091210165634.GF5086@lenovo>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
>  arch/x86/kernel/cpu/perf_event.c |   18 ++++++++++++------
>  1 files changed, 12 insertions(+), 6 deletions(-)
>
...

Btw, is there some particular reason to have x86_pmu::apic item?
Can't we use cpu_has_apic directly? Or there some plans about
this item? Or I miss something obvious?
 
	-- Cyrill

Re: [tip:perf/urgent] x86, perf events: Check if we have APIC enabled

[Christian Hartmann]

Hello list,

wow, I reported this bug also "PROBLEM: WARNING: at
arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy+0x32/0x3e()
(git 2.6.32-rc5)" on 22.october 09, this a delay of 1,5 month ;)
But anyway, good to know, that they comes now a hint from the kernel
by this patch... :)





2009/12/10 tip-bot for Cyrill Gorcunov <gorcunov@openvz.org>:
> Commit-ID:  125580380f418000b1a06d9a54700f1191b6e561
> Gitweb:     http://git.kernel.org/tip/125580380f418000b1a06d9a54700f1191b6e561
> Author:     Cyrill Gorcunov <gorcunov@openvz.org>
> AuthorDate: Thu, 10 Dec 2009 19:56:34 +0300
> Committer:  Ingo Molnar <mingo@elte.hu>
> CommitDate: Thu, 10 Dec 2009 18:00:30 +0100
>
> x86, perf events: Check if we have APIC enabled
>
> Ralf Hildebrandt reported this boot warning:
>
> | Running a vanilla 2.6.32 as Xen DomU, I'm getting:
> |
> | [    0.000999] CPU: Physical Processor ID: 0
> | [    0.000999] CPU: Processor Core ID: 1
> | [    0.000999] Performance Events: AMD PMU driver.
> | [    0.000999] ------------[ cut here ]------------
> | [    0.000999] WARNING: at arch/x86/kernel/apic/apic.c:249 native_apic_write_dummy
>
> So we need to check if APIC functionality is available, and
> not just in the P6 driver but elsewhere as well.
>
> Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de>
> Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Mike Galbraith <efault@gmx.de>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> LKML-Reference: <20091210165634.GF5086@lenovo>
> Signed-off-by: Ingo Molnar <mingo@elte.hu>
> ---
>  arch/x86/kernel/cpu/perf_event.c |   18 ++++++++++++------
>  1 files changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
> index 1342f23..18f05ec 100644
> --- a/arch/x86/kernel/cpu/perf_event.c
> +++ b/arch/x86/kernel/cpu/perf_event.c
> @@ -2066,12 +2066,6 @@ static __init int p6_pmu_init(void)
>
>        x86_pmu = p6_pmu;
>
> -       if (!cpu_has_apic) {
> -               pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
> -               pr_info("no hardware sampling interrupt available.\n");
> -               x86_pmu.apic = 0;
> -       }
> -
>        return 0;
>  }
>
> @@ -2163,6 +2157,16 @@ static __init int amd_pmu_init(void)
>        return 0;
>  }
>
> +static void __init pmu_check_apic(void)
> +{
> +       if (cpu_has_apic)
> +               return;
> +
> +       x86_pmu.apic = 0;
> +       pr_info("no APIC, boot with the \"lapic\" boot parameter to force-enable it.\n");
> +       pr_info("no hardware sampling interrupt available.\n");
> +}
> +
>  void __init init_hw_perf_events(void)
>  {
>        int err;
> @@ -2184,6 +2188,8 @@ void __init init_hw_perf_events(void)
>                return;
>        }
>
> +       pmu_check_apic();
> +
>        pr_cont("%s PMU driver.\n", x86_pmu.name);
>
>        if (x86_pmu.num_events > X86_PMC_MAX_GENERIC) {
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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