[PATCH]trace,x86: add x86 irq vector tracepoints

Seiji Aguchi
2012-07-03T22:34:30Z

As Vaibhav explained in the thread below, tracepoints for irq vectors
is useful.

http://www.spinics.net/lists/mm-commits/msg85707.html

<snip>
The current interrupt traces from irq_handler_entry and irq_handler_exit
provide when an interrupt is handled. They provide good data about when
the system has switched to kernel space and how it affects the currently
running processes.

There are some IRQ vectors which trigger the system into kernel space,
which are not handled in generic IRQ handlers. Tracing such events gives
us the information about IRQ interaction with other system events.

The trace also tells where the system is spending its time. We want to
know which cores are handling interrupts and how they are affecting other
processes in the system. Also, the trace provides information about when
the cores are idle and which interrupts are changing that state.
<snip>

On the other hand, my usecase is tracing just local timer event and
getting a value of instruction pointer.

I suggested to add an argument local timer event to get instruction pointer before.
But there is another way to get it with external module like systemtap.
So, I don't need to add any argument to irq vector tracepoints now.

Vaibhav's patch shared a trace point ,irq_vector_entry/irq_vector_exit, in all events.
But there is an above use case to trace specific irq_vector rather than tracing all events.
In this case, we are concerned about overhead due to unwanted events.

To reduce the overhead, this patch modifies Vaibhav's one to enable each event independently.

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>

---
arch/x86/kernel/apic/apic.c | 7 +
arch/x86/kernel/cpu/mcheck/therm_throt.c | 3 +
arch/x86/kernel/cpu/mcheck/threshold.c | 3 +
arch/x86/kernel/irq.c | 5 +
arch/x86/kernel/irq_work.c | 3 +
arch/x86/kernel/nmi.c | 3 +
arch/x86/kernel/smp.c | 7 +
arch/x86/mm/tlb.c | 3 +
include/trace/events/irq_vectors.h | 288 ++++++++++++++++++++++++++++++
9 files changed, 322 insertions(+), 0 deletions(-)
create mode 100644 include/trace/events/irq_vectors.h

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 39a222e..db219c9 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -34,6 +34,7 @@
#include <linux/dmi.h>
#include <linux/smp.h>
#include <linux/mm.h>
+#include <trace/events/irq_vectors.h>

#include <asm/irq_remapping.h>
#include <asm/perf_event.h>
@@ -895,7 +896,9 @@ void __irq_entry smp_apic_timer_interrupt(struct pt_regs *regs)
*/
irq_enter();
exit_idle();
+ trace_local_timer_entry(LOCAL_TIMER_VECTOR);
local_apic_timer_interrupt();
+ trace_local_timer_exit(LOCAL_TIMER_VECTOR);
irq_exit();

set_irq_regs(old_regs);
@@ -1881,6 +1884,7 @@ void smp_spurious_interrupt(struct pt_regs *regs)

irq_enter();
exit_idle();
+ trace_spurious_apic_entry(SPURIOUS_APIC_VECTOR);
/*
* Check if this really is a spurious interrupt and ACK it
* if it is a vectored one. Just in case...
@@ -1895,6 +1899,7 @@ void smp_spurious_interrupt(struct pt_regs *regs)
/* see sw-dev-man vol 3, chapter 7.4.13.5 */
pr_info("spurious APIC interrupt on CPU#%d, "
"should never happen.\n", smp_processor_id());
+ trace_spurious_apic_exit(SPURIOUS_APIC_VECTOR);
irq_exit();
}

@@ -1918,6 +1923,7 @@ void smp_error_interrupt(struct pt_regs *regs)

irq_enter();
exit_idle();
+ trace_error_apic_entry(ERROR_APIC_VECTOR);
/* First tickle the hardware, only then report what went on. -- REW */
v0 = apic_read(APIC_ESR);
apic_write(APIC_ESR, 0);
@@ -1938,6 +1944,7 @@ void smp_error_interrupt(struct pt_regs *regs)

apic_printk(APIC_DEBUG, KERN_CONT "\n");

+ trace_error_apic_exit(ERROR_APIC_VECTOR);
irq_exit();
}

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index 47a1870..79cc87a 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -23,6 +23,7 @@
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/cpu.h>
+#include <trace/events/irq_vectors.h>

#include <asm/processor.h>
#include <asm/apic.h>
@@ -382,8 +383,10 @@ asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
{
irq_enter();
exit_idle();
+ trace_thermal_apic_entry(THERMAL_APIC_VECTOR);
inc_irq_stat(irq_thermal_count);
smp_thermal_vector();
+ trace_thermal_apic_exit(THERMAL_APIC_VECTOR);
irq_exit();
/* Ack only at the end to avoid potential reentry */
ack_APIC_irq();
diff --git a/arch/x86/kernel/cpu/mcheck/threshold.c b/arch/x86/kernel/cpu/mcheck/threshold.c
index aa578ca..45f33a3 100644
--- a/arch/x86/kernel/cpu/mcheck/threshold.c
+++ b/arch/x86/kernel/cpu/mcheck/threshold.c
@@ -3,6 +3,7 @@
*/
#include <linux/interrupt.h>
#include <linux/kernel.h>
+#include <trace/events/irq_vectors.h>

#include <asm/irq_vectors.h>
#include <asm/apic.h>
@@ -21,8 +22,10 @@ asmlinkage void smp_threshold_interrupt(void)
{
irq_enter();
exit_idle();
+ trace_threshold_apic_entry(THRESHOLD_APIC_VECTOR);
inc_irq_stat(irq_threshold_count);
mce_threshold_vector();
+ trace_threshold_apic_exit(THRESHOLD_APIC_VECTOR);
irq_exit();
/* Ack only at the end to avoid potential reentry */
ack_APIC_irq();
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c
index 3dafc60..e6786a1 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -18,6 +18,9 @@
#include <asm/mce.h>
#include <asm/hw_irq.h>

+#define CREATE_TRACE_POINTS
+#include <trace/events/irq_vectors.h>
+
atomic_t irq_err_count;

/* Function pointer for generic interrupt vector handling */
@@ -218,11 +221,13 @@ void smp_x86_platform_ipi(struct pt_regs *regs)

exit_idle();

+ trace_x86_platform_ipi_entry(X86_PLATFORM_IPI_VECTOR);
inc_irq_stat(x86_platform_ipis);

if (x86_platform_ipi_callback)
x86_platform_ipi_callback();

+ trace_x86_platform_ipi_exit(X86_PLATFORM_IPI_VECTOR);
irq_exit();

set_irq_regs(old_regs);
diff --git a/arch/x86/kernel/irq_work.c b/arch/x86/kernel/irq_work.c
index ca8f703..2cf7505 100644
--- a/arch/x86/kernel/irq_work.c
+++ b/arch/x86/kernel/irq_work.c
@@ -8,13 +8,16 @@
#include <linux/irq_work.h>
#include <linux/hardirq.h>
#include <asm/apic.h>
+#include <trace/events/irq_vectors.h>

void smp_irq_work_interrupt(struct pt_regs *regs)
{
irq_enter();
ack_APIC_irq();
+ trace_irq_work_entry(IRQ_WORK_VECTOR);
inc_irq_stat(apic_irq_work_irqs);
irq_work_run();
+ trace_irq_work_exit(IRQ_WORK_VECTOR);
irq_exit();
}

diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index a0b2f84..84e8102 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -28,6 +28,7 @@
#include <asm/mach_traps.h>
#include <asm/nmi.h>
#include <asm/x86_init.h>
+#include <trace/events/irq_vectors.h>

struct nmi_desc {
spinlock_t lock;
@@ -463,12 +464,14 @@ do_nmi(struct pt_regs *regs, long error_code)
nmi_nesting_preprocess(regs);

nmi_enter();
+ trace_nmi_entry(NMI_VECTOR);

inc_irq_stat(__nmi_count);

if (!ignore_nmis)
default_do_nmi(regs);

+ trace_nmi_exit(NMI_VECTOR);
nmi_exit();

/* On i386, may loop back to preprocess */
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 48d2b7d..5b2d6de 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -23,6 +23,7 @@
#include <linux/interrupt.h>
#include <linux/cpu.h>
#include <linux/gfp.h>
+#include <trace/events/irq_vectors.h>

#include <asm/mtrr.h>
#include <asm/tlbflush.h>
@@ -252,8 +253,10 @@ finish:
void smp_reschedule_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
+ trace_reschedule_entry(RESCHEDULE_VECTOR);
inc_irq_stat(irq_resched_count);
scheduler_ipi();
+ trace_reschedule_exit(RESCHEDULE_VECTOR);
/*
* KVM uses this interrupt to force a cpu out of guest mode
*/
@@ -263,8 +266,10 @@ void smp_call_function_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
irq_enter();
+ trace_call_function_entry(CALL_FUNCTION_VECTOR);
generic_smp_call_function_interrupt();
inc_irq_stat(irq_call_count);
+ trace_call_function_exit(CALL_FUNCTION_VECTOR);
irq_exit();
}

@@ -272,8 +277,10 @@ void smp_call_function_single_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
irq_enter();
+ trace_call_function_single_entry(CALL_FUNCTION_SINGLE_VECTOR);
generic_smp_call_function_single_interrupt();
inc_irq_stat(irq_call_count);
+ trace_call_function_single_exit(CALL_FUNCTION_SINGLE_VECTOR);
irq_exit();
}

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 5e57e11..8a66e91 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -5,6 +5,7 @@
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/module.h>
+#include <trace/events/irq_vectors.h>
#include <linux/cpu.h>

#include <asm/tlbflush.h>
@@ -143,6 +144,7 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
sender = ~regs->orig_ax - INVALIDATE_TLB_VECTOR_START;
f = &flush_state[sender];

+ trace_invalidate_tlb_entry(INVALIDATE_TLB_VECTOR_START + sender);
if (!cpumask_test_cpu(cpu, to_cpumask(f->flush_cpumask)))
goto out;
/*
@@ -169,6 +171,7 @@ out:
cpumask_clear_cpu(cpu, to_cpumask(f->flush_cpumask));
smp_mb__after_clear_bit();
inc_irq_stat(irq_tlb_count);
+ trace_invalidate_tlb_exit(INVALIDATE_TLB_VECTOR_START + sender);
}

static void flush_tlb_others_ipi(const struct cpumask *cpumask,
diff --git a/include/trace/events/irq_vectors.h b/include/trace/events/irq_vectors.h
new file mode 100644
index 0000000..4c1cb4e
--- /dev/null
+++ b/include/trace/events/irq_vectors.h
@@ -0,0 +1,288 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM irq_vectors
+
+#if !defined(_TRACE_IRQ_VECTORS_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_IRQ_VECTORS_H
+
+#include <linux/tracepoint.h>
+#include <asm/irq.h>
+
+DECLARE_EVENT_CLASS(irq_vector,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq),
+
+ TP_STRUCT__entry(
+ __field( int, irq )
+ ),
+
+ TP_fast_assign(
+ __entry->irq = irq;
+ ),
+
+ TP_printk("irq=%d", __entry->irq)
+);
+
+/*
+ * nmi_entry - called before enterring a nmi vector handler
+ */
+DEFINE_EVENT(irq_vector, nmi_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * nmi_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, nmi_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * local_timer_entry - called before enterring a local timer interrupt
+ * vector handler
+ */
+DEFINE_EVENT(irq_vector, local_timer_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * local_timer_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, local_timer_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * error_apic_entry - called before enterring an error apic vector handler
+ */
+DEFINE_EVENT(irq_vector, error_apic_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * error_apic_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, error_apic_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * reschedule_entry - called before enterring a reschedule vector handler
+ */
+DEFINE_EVENT(irq_vector, reschedule_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * reschedule_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, reschedule_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * call_function_entry - called before enterring a call function
+ * vector handler
+ */
+DEFINE_EVENT(irq_vector, call_function_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * call_function_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, call_function_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * call_function_single_entry - called before enterring a call function
+ * single vector handler
+ */
+DEFINE_EVENT(irq_vector, call_function_single_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * call_function_single_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, call_function_single_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * thermal_apic_entry - called before enterring a thermal apic vector handler
+ */
+DEFINE_EVENT(irq_vector, thermal_apic_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * thermal_apic_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, thermal_apic_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * threshold_apic_entry - called before enterring a threshold apic
+ * vector handler
+ */
+DEFINE_EVENT(irq_vector, threshold_apic_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * threshold_apic_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, threshold_apic_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * spurious_apic_entry - called before enterring a spurious apic vector handler
+ */
+DEFINE_EVENT(irq_vector, spurious_apic_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * spurious_apic_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, spurious_apic_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * irq_work_entry - called before enterring an irq work vector handler
+ */
+DEFINE_EVENT(irq_vector, irq_work_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * irq_work_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, irq_work_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * x86_platform_ipi_entry - called before enterring a x86 platform ipi
+ * vector handler
+ */
+DEFINE_EVENT(irq_vector, x86_platform_ipi_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * x86_platform_ipi_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, x86_platform_ipi_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * invalidate_tlb_entry - called before enterring an invalidate tlb
+ * vector handler
+ */
+DEFINE_EVENT(irq_vector, invalidate_tlb_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * invalidate_tlb_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, invalidate_tlb_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+#endif /* _TRACE_IRQ_VECTORS_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
1.7.1