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.

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.

Signed-off-by: Vaibhav Nagarnaik <vnagarnaik@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Michael Rubin <mrubin@google.com>
Cc: David Sharp <dhsharp@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/include/asm/irq_vectors.h b/arch/x86/include/asm/irq_vectors.h
index f9a320984a105e2c7a82bfd61d4ab76aadee8141..386b69ee52fb04c5f813ed0506ed0bae0bd3471e 100644 (file)
--- a/arch/x86/include/asm/irq_vectors.h
+++ b/arch/x86/include/asm/irq_vectors.h
@@ -181,4 +181,54 @@ 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 52fa56399a5021664eca08743d9cd8eec1108b7e..0fe559f3639be5d9dc35e16a86ecd434bf582cef 100644 (file)
--- 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/perf_event.h>
 #include <asm/x86_init.h>
@@ -859,7 +860,9 @@ 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);
@@ -1793,6 +1796,7 @@ 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...
@@ -1807,6 +1811,7 @@ 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();
 }
 
@@ -1830,6 +1835,7 @@ 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);
@@ -1850,6 +1856,7 @@ 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 787e06c84ea6a8cf6e097e15c4b13c2db87dbb7a..6b7edb53f00a0c84c865ad2894121742ef655e04 100644 (file)
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -24,6 +24,7 @@
 #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>
@@ -399,8 +400,10 @@ 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 d746df2909c9fe306d20f1e5288cc476c5777209..ffde17bdd85adb1979964a60c60986cf5c722cc6 100644 (file)
--- 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 429e0c92924eede7d925c92836ac25505de86007..64aad37c0ff09df3999e8ce808ab1a58006952a3 100644 (file)
--- 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 */
@@ -212,12 +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 ca8f703a1e70bdaf219bdcdd215ac2e1724bfda6..107754c8d8ec7436ab33df49d5f9d214ee68decc 100644 (file)
--- 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 16204dc1548427d8895b6ce7da1436d81ecfe431..17c5d01868e0c13120eb23ebdb0a75d9419aa821 100644 (file)
--- 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>
@@ -200,8 +201,10 @@ 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
         */
@@ -211,8 +214,10 @@ 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();
 }
 
@@ -220,8 +225,10 @@ 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/traps.c b/arch/x86/kernel/traps.c
index 9682ec50180c1b732996773bfa4feafa18c6c116..6e8fbca48c377d65d16da832ca9ba0822f2c4ba3 100644 (file)
--- 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 d6c0418c3e4711795158b52e57b2fa337848d03c..bf9475d97307d80291028243e8e9bd611ce4b7da 100644 (file)
--- 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 (file)
index 0000000..699ddaa
--- /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>
+#include <asm/irq.h>
+
+#ifndef irq_vector_name_table
+#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>