Patchwork powerpc: Add accounting for Doorbell interrupts

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Submitter Ian Munsie
Date March 20, 2013, 7:42 a.m.
Message ID <1363765332-28461-1-git-send-email-imunsie@au1.ibm.com>
Download mbox | patch
Permalink /patch/229258/
State Superseded, archived
Delegated to: Michael Ellerman
Headers show

Comments

Ian Munsie - March 20, 2013, 7:42 a.m.
From: Ian Munsie <imunsie@au1.ibm.com>

This patch adds a new line to /proc/interrupts to account for the
doorbell interrupts that each hardware thread has received. The total
interrupt count in /proc/stat will now also include doorbells.

 # cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
 16:        551       1267        281        175      XICS Level     IPI
LOC:       2037       1503       1688       1625   Local timer interrupts
SPU:          0          0          0          0   Spurious interrupts
CNT:          0          0          0          0   Performance monitoring interrupts
MCE:          0          0          0          0   Machine check exceptions
DBL:         42        550         20         91   Doorbell interrupts

Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
---
 arch/powerpc/include/asm/hardirq.h |    1 +
 arch/powerpc/kernel/dbell.c        |    2 ++
 arch/powerpc/kernel/irq.c          |    8 ++++++++
 3 files changed, 11 insertions(+)
Michael Neuling - March 21, 2013, 12:28 a.m.
> From: Ian Munsie <imunsie@au1.ibm.com>
> 
> This patch adds a new line to /proc/interrupts to account for the
> doorbell interrupts that each hardware thread has received. The total
> interrupt count in /proc/stat will now also include doorbells.

It's probably worth noting in the comment that these are not being
accounted at all currently, even in the existing IPI line in
/proc/interrupts.

Mikey

>  # cat /proc/interrupts
>            CPU0       CPU1       CPU2       CPU3
>  16:        551       1267        281        175      XICS Level     IPI
> LOC:       2037       1503       1688       1625   Local timer interrupts
> SPU:          0          0          0          0   Spurious interrupts
> CNT:          0          0          0          0   Performance monitoring interrupts
> MCE:          0          0          0          0   Machine check exceptions
> DBL:         42        550         20         91   Doorbell interrupts
>
> 
> Signed-off-by: Ian Munsie <imunsie@au1.ibm.com>
> ---
>  arch/powerpc/include/asm/hardirq.h |    1 +
>  arch/powerpc/kernel/dbell.c        |    2 ++
>  arch/powerpc/kernel/irq.c          |    8 ++++++++
>  3 files changed, 11 insertions(+)
> 
> diff --git a/arch/powerpc/include/asm/hardirq.h b/arch/powerpc/include/asm/hardirq.h
> index 3147a29..e88c5f2 100644
> --- a/arch/powerpc/include/asm/hardirq.h
> +++ b/arch/powerpc/include/asm/hardirq.h
> @@ -10,6 +10,7 @@ typedef struct {
>  	unsigned int pmu_irqs;
>  	unsigned int mce_exceptions;
>  	unsigned int spurious_irqs;
> +	unsigned int doorbell_irqs;
>  } ____cacheline_aligned irq_cpustat_t;
>  
>  DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
> diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c
> index 9ebbc24..d55c76c 100644
> --- a/arch/powerpc/kernel/dbell.c
> +++ b/arch/powerpc/kernel/dbell.c
> @@ -41,6 +41,8 @@ void doorbell_exception(struct pt_regs *regs)
>  
>  	may_hard_irq_enable();
>  
> +	__get_cpu_var(irq_stat).doorbell_irqs++;
> +
>  	smp_ipi_demux();
>  
>  	irq_exit();
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index 4f97fe3..3a3c3b9 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -374,6 +374,13 @@ int arch_show_interrupts(struct seq_file *p, int prec)
>  		seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
>  	seq_printf(p, "  Machine check exceptions\n");
>  
> +	if (cpu_has_feature(CPU_FTR_DBELL)) {
> +		seq_printf(p, "%*s: ", prec, "DBL");
> +		for_each_online_cpu(j)
> +			seq_printf(p, "%10u ", per_cpu(irq_stat, j).doorbell_irqs);
> +		seq_printf(p, "  Doorbell interrupts\n");
> +	}
> +
>  	return 0;
>  }
>  
> @@ -387,6 +394,7 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
>  	sum += per_cpu(irq_stat, cpu).pmu_irqs;
>  	sum += per_cpu(irq_stat, cpu).mce_exceptions;
>  	sum += per_cpu(irq_stat, cpu).spurious_irqs;
> +	sum += per_cpu(irq_stat, cpu).doorbell_irqs;
>  
>  	return sum;
>  }
> -- 
> 1.7.10.4
>
Michael Ellerman - March 22, 2013, 4:18 a.m.
On Wed, Mar 20, 2013 at 06:42:12PM +1100, Ian Munsie wrote:
> From: Ian Munsie <imunsie@au1.ibm.com>
> 
> This patch adds a new line to /proc/interrupts to account for the
> doorbell interrupts that each hardware thread has received. The total
> interrupt count in /proc/stat will now also include doorbells.

Should it be inside CONFIG_PPC_DOORBELL ?

cheers
Ian Munsie - March 22, 2013, 5:13 a.m.
Excerpts from Michael Ellerman's message of 2013-03-22 15:18:03 +1100:
> On Wed, Mar 20, 2013 at 06:42:12PM +1100, Ian Munsie wrote:
> > From: Ian Munsie <imunsie@au1.ibm.com>
> > 
> > This patch adds a new line to /proc/interrupts to account for the
> > doorbell interrupts that each hardware thread has received. The total
> > interrupt count in /proc/stat will now also include doorbells.
> 
> Should it be inside CONFIG_PPC_DOORBELL ?

The doorbell line will only show up in /proc/interrupt if CPU_FTR_DBELL
is set and the total interrupt count in /proc/stat will be unaffected
if we don't have doorbells (+ 0 doorbells). It still builds fine without
CONFIG_PPC_DOORBELL.

Adding #ifdefs would save one per cpu integer in irq_stat. I can throw
together a v2 patch with them in place.

Cheers,
-Ian

Patch

diff --git a/arch/powerpc/include/asm/hardirq.h b/arch/powerpc/include/asm/hardirq.h
index 3147a29..e88c5f2 100644
--- a/arch/powerpc/include/asm/hardirq.h
+++ b/arch/powerpc/include/asm/hardirq.h
@@ -10,6 +10,7 @@  typedef struct {
 	unsigned int pmu_irqs;
 	unsigned int mce_exceptions;
 	unsigned int spurious_irqs;
+	unsigned int doorbell_irqs;
 } ____cacheline_aligned irq_cpustat_t;
 
 DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
diff --git a/arch/powerpc/kernel/dbell.c b/arch/powerpc/kernel/dbell.c
index 9ebbc24..d55c76c 100644
--- a/arch/powerpc/kernel/dbell.c
+++ b/arch/powerpc/kernel/dbell.c
@@ -41,6 +41,8 @@  void doorbell_exception(struct pt_regs *regs)
 
 	may_hard_irq_enable();
 
+	__get_cpu_var(irq_stat).doorbell_irqs++;
+
 	smp_ipi_demux();
 
 	irq_exit();
diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index 4f97fe3..3a3c3b9 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/arch/powerpc/kernel/irq.c
@@ -374,6 +374,13 @@  int arch_show_interrupts(struct seq_file *p, int prec)
 		seq_printf(p, "%10u ", per_cpu(irq_stat, j).mce_exceptions);
 	seq_printf(p, "  Machine check exceptions\n");
 
+	if (cpu_has_feature(CPU_FTR_DBELL)) {
+		seq_printf(p, "%*s: ", prec, "DBL");
+		for_each_online_cpu(j)
+			seq_printf(p, "%10u ", per_cpu(irq_stat, j).doorbell_irqs);
+		seq_printf(p, "  Doorbell interrupts\n");
+	}
+
 	return 0;
 }
 
@@ -387,6 +394,7 @@  u64 arch_irq_stat_cpu(unsigned int cpu)
 	sum += per_cpu(irq_stat, cpu).pmu_irqs;
 	sum += per_cpu(irq_stat, cpu).mce_exceptions;
 	sum += per_cpu(irq_stat, cpu).spurious_irqs;
+	sum += per_cpu(irq_stat, cpu).doorbell_irqs;
 
 	return sum;
 }