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Subject[PATCH v2] trace: Add x86 irq vector entry/exit tracepoints
Date
From: Jiaying Zhang <jiayingz@google.com>

The current interrupt trace of irq_handler_entry and irq_handler_exit
give traces of when an interrupt is handled. They provide good data
about when the system is running in kernel space and how it affects the
currently running applications.

Apart from this, they are IRQ vectors which trigger the system into
kernel space. Tracing such events gives us the trace of 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.

The following patch adds the event definition and trace instrumentation
for interrupt vectors. For x86, a lookup table is provided to print out
readable IRQ vector names. The template can be used to provide interrupt
vector lookup tables on other architectures.

With this patch, following interrupt vectors are logged by ftrace
(when enabled):

Interrupt as in /proc/interrupts Name as it appears in ftrace log
NMI: Non-maskable interrupts : NMI_VECTOR
LOC: Local timer interrupts : LOCAL_TIMER_VECTOR
SPU: Spurious interrupts : SPURIOUS_APIC_VECTOR
PMI: Performance monitoring interrupts : <not added>
IWI: IRQ work interrupts : IRQ_WORK_VECTOR
RES: Rescheduling interrupts : RESCHEDULE_VECTOR
CAL: Function call interrupts : CALL_FUNCTION_VECTOR or
CALL_FUNCTION_SINGLE_VECTOR
TLB: TLB shootdowns : INVALIDATE_TLB_VECTOR_START to
INVALIDATE_TLB_VECTOR_END
TRM: Thermal event interrupts : THERMAL_APIC_VECTOR
THR: Threshold APIC interrupts : THRESHOLD_APIC_VECTOR
MCE: Machine check exceptions : <not added>
MCP: Machine check polls : <not added>
ERR: : ERROR_APIC_VECTOR
MIS: : <not added>
PLT: Platform interrupts : X86_PLATFORM_IPI_VECTOR

$ sh ~/ftrace_test.sh
tracing...
cpu0: overrun: 0
cpu1: overrun: 0
cpu2: overrun: 0
cpu3: overrun: 0
IRQ ftrace record counts (ignoring numeric irq=(0|1|4|5|7|9|10|24) )
2 irq=242 name=INVALIDATE_TLB_VECTOR_2
3 irq=252 name=CALL_FUNCTION_VECTOR
6 irq=241 name=INVALIDATE_TLB_VECTOR_1
6 irq=2 name=NMI_VECTOR
22 irq=240 name=INVALIDATE_TLB_VECTOR_0
40 irq=251 name=CALL_FUNCTION_SINGLE_VECTOR
587 irq=253 name=RESCHEDULE_VECTOR
15013 irq=239 name=LOCAL_TIMER_VECTOR
/proc/interrupts stats difference
6 NMI (Non-maskable interrupts)
14945 LOC (Local timer interrupts)
6 PMI (Performance monitoring interrupts)
578 RES (Rescheduling interrupts)
42 CAL (Function call interrupts)
30 TLB (TLB shootdowns)
4 MCP (Machine check polls)
In above output:
NMI (Non-maskable interrupts) == NMI_VECTOR (irq 2)
LOC (Local timer interrupts) == LOCAL_TIMER_VECTOR (irq 239)
RES (Rescheduling interrupts) == RESCHEDULE_VECTOR (irq=253)
CAL (Function call interrupts) == CALL_FUNCTION_VECTOR (irq 252) +
CALL_FUNCTION_SINGLE_VECTOR (irq 251)
TLB (TLB shootdowns) == INVALIDATE_TLB_VECTOR_0 (irq=240) +
INVALIDATE_TLB_VECTOR_1 (irq=241) +
INVALIDATE_TLB_VECTOR_2 (irq=242)

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
---
Changelog:
v1-v2
* Move the irq_vector_{entry|exit} tracepoints under irq_vectors/ sub
folder
* Rebased to 3.0.0
arch/x86/include/asm/irq_vectors.h | 50 ++++++++++++++++++++++++++
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 | 7 +++-
arch/x86/kernel/irq_work.c | 3 ++
arch/x86/kernel/smp.c | 7 ++++
arch/x86/kernel/time.c | 16 +++++---
arch/x86/kernel/traps.c | 3 ++
arch/x86/mm/tlb.c | 3 ++
include/trace/events/irq_vectors.h | 56 ++++++++++++++++++++++++++++++
11 files changed, 151 insertions(+), 7 deletions(-)
create mode 100644 include/trace/events/irq_vectors.h
diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index 6e976ee..af06349 100644
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -182,4 +182,54 @@ static inline int invalid_vm86_irq(int irq)
# define NR_IRQS NR_IRQS_LEGACY
#endif

+#define irq_vector_name(sirq) { sirq, #sirq }
+#define invalidate_tlb_vector_name(i) { INVALIDATE_TLB_VECTOR_END-31+i, \
+ "INVALIDATE_TLB_VECTOR" }
+
+#define irq_vector_name_table \
+ irq_vector_name(NMI_VECTOR), \
+ irq_vector_name(LOCAL_TIMER_VECTOR), \
+ irq_vector_name(ERROR_APIC_VECTOR), \
+ irq_vector_name(RESCHEDULE_VECTOR), \
+ irq_vector_name(CALL_FUNCTION_VECTOR), \
+ irq_vector_name(CALL_FUNCTION_SINGLE_VECTOR), \
+ irq_vector_name(THERMAL_APIC_VECTOR), \
+ irq_vector_name(THRESHOLD_APIC_VECTOR), \
+ irq_vector_name(REBOOT_VECTOR), \
+ irq_vector_name(SPURIOUS_APIC_VECTOR), \
+ irq_vector_name(IRQ_WORK_VECTOR), \
+ irq_vector_name(X86_PLATFORM_IPI_VECTOR), \
+ invalidate_tlb_vector_name(0), \
+ invalidate_tlb_vector_name(1), \
+ invalidate_tlb_vector_name(2), \
+ invalidate_tlb_vector_name(3), \
+ invalidate_tlb_vector_name(4), \
+ invalidate_tlb_vector_name(5), \
+ invalidate_tlb_vector_name(6), \
+ invalidate_tlb_vector_name(7), \
+ invalidate_tlb_vector_name(8), \
+ invalidate_tlb_vector_name(9), \
+ invalidate_tlb_vector_name(10), \
+ invalidate_tlb_vector_name(11), \
+ invalidate_tlb_vector_name(12), \
+ invalidate_tlb_vector_name(13), \
+ invalidate_tlb_vector_name(14), \
+ invalidate_tlb_vector_name(15), \
+ invalidate_tlb_vector_name(16), \
+ invalidate_tlb_vector_name(17), \
+ invalidate_tlb_vector_name(18), \
+ invalidate_tlb_vector_name(19), \
+ invalidate_tlb_vector_name(20), \
+ invalidate_tlb_vector_name(21), \
+ invalidate_tlb_vector_name(22), \
+ invalidate_tlb_vector_name(23), \
+ invalidate_tlb_vector_name(24), \
+ invalidate_tlb_vector_name(25), \
+ invalidate_tlb_vector_name(26), \
+ invalidate_tlb_vector_name(27), \
+ invalidate_tlb_vector_name(28), \
+ invalidate_tlb_vector_name(29), \
+ invalidate_tlb_vector_name(30), \
+ invalidate_tlb_vector_name(31)
+
#endif /* _ASM_X86_IRQ_VECTORS_H */
diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index b961af8..f09f54c 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -33,6 +33,7 @@
#include <linux/dmi.h>
#include <linux/smp.h>
#include <linux/mm.h>
+#include <trace/events/irq_vectors.h>

#include <asm/perf_event.h>
#include <asm/x86_init.h>
@@ -857,7 +858,9 @@ void __irq_entry smp_apic_timer_interrupt(struct pt_regs *regs)
*/
exit_idle();
irq_enter();
+ trace_irq_vector_entry(LOCAL_TIMER_VECTOR);
local_apic_timer_interrupt();
+ trace_irq_vector_exit(LOCAL_TIMER_VECTOR);
irq_exit();

set_irq_regs(old_regs);
@@ -1791,6 +1794,7 @@ void smp_spurious_interrupt(struct pt_regs *regs)

exit_idle();
irq_enter();
+ trace_irq_vector_entry(SPURIOUS_APIC_VECTOR);
/*
* Check if this really is a spurious interrupt and ACK it
* if it is a vectored one. Just in case...
@@ -1805,6 +1809,7 @@ 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_irq_vector_exit(SPURIOUS_APIC_VECTOR);
irq_exit();
}

@@ -1828,6 +1833,7 @@ void smp_error_interrupt(struct pt_regs *regs)

exit_idle();
irq_enter();
+ trace_irq_vector_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);
@@ -1848,6 +1854,7 @@ void smp_error_interrupt(struct pt_regs *regs)

apic_printk(APIC_DEBUG, KERN_CONT "\n");

+ trace_irq_vector_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 27c6251..bd8fa96 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/system.h>
@@ -398,8 +399,10 @@ asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
{
exit_idle();
irq_enter();
+ trace_irq_vector_entry(THERMAL_APIC_VECTOR);
inc_irq_stat(irq_thermal_count);
smp_thermal_vector();
+ trace_irq_vector_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 d746df2..ffde17b 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)
{
exit_idle();
irq_enter();
+ trace_irq_vector_entry(THRESHOLD_APIC_VECTOR);
inc_irq_stat(irq_threshold_count);
mce_threshold_vector();
+ trace_irq_vector_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 6c0802e..1fb134e 100644
--- a/arch/x86/kernel/irq.c
+++ b/arch/x86/kernel/irq.c
@@ -17,6 +17,10 @@
#include <asm/mce.h>
#include <asm/hw_irq.h>

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

/* Function pointer for generic interrupt vector handling */
@@ -211,12 +215,13 @@ void smp_x86_platform_ipi(struct pt_regs *regs)
exit_idle();

irq_enter();
-
+ trace_irq_vector_entry(X86_PLATFORM_IPI_VECTOR);
inc_irq_stat(x86_platform_ipis);

if (x86_platform_ipi_callback)
x86_platform_ipi_callback();

+ trace_irq_vector_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..107754c 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_vector_entry(IRQ_WORK_VECTOR);
inc_irq_stat(apic_irq_work_irqs);
irq_work_run();
+ trace_irq_vector_exit(IRQ_WORK_VECTOR);
irq_exit();
}

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 013e7eb..1b0ac99 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -22,6 +22,7 @@
#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>
@@ -199,8 +200,10 @@ static void native_stop_other_cpus(int wait)
void smp_reschedule_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
+ trace_irq_vector_entry(RESCHEDULE_VECTOR);
inc_irq_stat(irq_resched_count);
scheduler_ipi();
+ trace_irq_vector_exit(RESCHEDULE_VECTOR);
/*
* KVM uses this interrupt to force a cpu out of guest mode
*/
@@ -210,8 +213,10 @@ void smp_call_function_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
irq_enter();
+ trace_irq_vector_entry(CALL_FUNCTION_VECTOR);
generic_smp_call_function_interrupt();
inc_irq_stat(irq_call_count);
+ trace_irq_vector_exit(CALL_FUNCTION_VECTOR);
irq_exit();
}

@@ -219,8 +224,10 @@ void smp_call_function_single_interrupt(struct pt_regs *regs)
{
ack_APIC_irq();
irq_enter();
+ trace_irq_vector_entry(CALL_FUNCTION_SINGLE_VECTOR);
generic_smp_call_function_single_interrupt();
inc_irq_stat(irq_call_count);
+ trace_irq_vector_exit(CALL_FUNCTION_SINGLE_VECTOR);
irq_exit();
}

diff --git a/arch/x86/kernel/time.c b/arch/x86/kernel/time.c
index 00cbb27..799c781 100644
--- a/arch/x86/kernel/time.c
+++ b/arch/x86/kernel/time.c
@@ -13,6 +13,7 @@
#include <linux/interrupt.h>
#include <linux/time.h>
#include <linux/mca.h>
+#include <trace/events/irq.h>

#include <asm/vsyscall.h>
#include <asm/x86_init.h>
@@ -51,6 +52,13 @@ unsigned long profile_pc(struct pt_regs *regs)
}
EXPORT_SYMBOL(profile_pc);

+static irqreturn_t timer_interrupt(int irq, void *dev_id);
+static struct irqaction irq0 = {
+ .handler = timer_interrupt,
+ .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
+ .name = "timer"
+};
+
/*
* Default timer interrupt handler for PIT/HPET
*/
@@ -59,7 +67,9 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
/* Keep nmi watchdog up to date */
inc_irq_stat(irq0_irqs);

+ trace_irq_handler_entry(0, &irq0);
global_clock_event->event_handler(global_clock_event);
+ trace_irq_handler_exit(0, &irq0, 1);

/* MCA bus quirk: Acknowledge irq0 by setting bit 7 in port 0x61 */
if (MCA_bus)
@@ -68,12 +78,6 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id)
return IRQ_HANDLED;
}

-static struct irqaction irq0 = {
- .handler = timer_interrupt,
- .flags = IRQF_DISABLED | IRQF_NOBALANCING | IRQF_IRQPOLL | IRQF_TIMER,
- .name = "timer"
-};
-
void __init setup_default_timer_irq(void)
{
setup_irq(0, &irq0);
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index b9b6716..1725502 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -31,6 +31,7 @@
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/io.h>
+#include <trace/events/irq_vectors.h>

#ifdef CONFIG_EISA
#include <linux/ioport.h>
@@ -434,12 +435,14 @@ dotraplinkage notrace __kprobes void
do_nmi(struct pt_regs *regs, long error_code)
{
nmi_enter();
+ trace_irq_vector_entry(NMI_VECTOR);

inc_irq_stat(__nmi_count);

if (!ignore_nmis)
default_do_nmi(regs);

+ trace_irq_vector_exit(NMI_VECTOR);
nmi_exit();
}

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index d6c0418..bf9475d 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>
@@ -141,6 +142,7 @@ void smp_invalidate_interrupt(struct pt_regs *regs)
sender = ~regs->orig_ax - INVALIDATE_TLB_VECTOR_START;
f = &flush_state[sender];

+ trace_irq_vector_entry(INVALIDATE_TLB_VECTOR_START + sender);
if (!cpumask_test_cpu(cpu, to_cpumask(f->flush_cpumask)))
goto out;
/*
@@ -167,6 +169,7 @@ out:
cpumask_clear_cpu(cpu, to_cpumask(f->flush_cpumask));
smp_mb__after_clear_bit();
inc_irq_stat(irq_tlb_count);
+ trace_irq_vector_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..a1b94ff
--- /dev/null
+++ b/include/trace/events/irq_vectors.h
@@ -0,0 +1,56 @@
+#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>
+
+#ifndef irq_vector_name_table
+#warn "irq_vector_name_table not defined!"
+#define irq_vector_name_table { -1, NULL }
+#endif
+
+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 name=%s", __entry->irq,
+ __print_symbolic(__entry->irq, irq_vector_name_table))
+);
+
+/*
+ * irq_vector_entry - called before enterring a interrupt vector handler
+ */
+DEFINE_EVENT(irq_vector, irq_vector_entry,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+/*
+ * irq_vector_exit - called immediately after the interrupt vector
+ * handler returns
+ */
+DEFINE_EVENT(irq_vector, irq_vector_exit,
+
+ TP_PROTO(int irq),
+
+ TP_ARGS(irq)
+);
+
+#endif /* _TRACE_IRQ_VECTORS_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
--
1.7.3.1


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