These patches add trace events support for preempt and irq disable/enable
events. This version has few changes suggested by Steven as well.
I am looking forward to getting these accepted for v4.15 if possible. I based
it on Linus's master, please let me know if there is another branch I need to
rebase on. thanks!
Changes since v4:
- Use static inline instead of defines for tracer functions.
- Moved new per-cpu variables to protect from recursion to the correct defines.
- Dropped bug fix patch (3/3) not related to series and will submit that separately.
Here's an example of how Android's systrace will be using it to show critical
sections as a gantt chart: http://imgur.com/download/TZplEVp
Links to earlier series:
v4: https://lkml.org/lkml/2017/9/6/724
v3: https://lkml.org/lkml/2017/9/3/15
Joel Fernandes (2):
tracing: Prepare to add preempt and irq trace events
tracing: Add support for preempt and irq enable/disable events
include/linux/ftrace.h | 3 +-
include/linux/irqflags.h | 4 +-
include/trace/events/preemptirq.h | 62 ++++++++++++++
kernel/trace/Kconfig | 9 ++
kernel/trace/Makefile | 1 +
kernel/trace/trace_irqsoff.c | 176 +++++++++++++++++++++++++++++++-------
6 files changed, 222 insertions(+), 33 deletions(-)
create mode 100644 include/trace/events/preemptirq.h
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
--
2.14.1.581.gf28d330327-goog
In preparation of adding irq and preempts enable and disable trace events, move
required functions and code to make it easier to add these events in a later
patch. This patch is just code movement and no functional change.
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: [email protected]
Signed-off-by: Joel Fernandes <[email protected]>
---
kernel/trace/trace_irqsoff.c | 121 ++++++++++++++++++++++++++++++++-----------
1 file changed, 91 insertions(+), 30 deletions(-)
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 7758bc0617cb..26c688740742 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -16,6 +16,7 @@
#include "trace.h"
+#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
static struct trace_array *irqsoff_trace __read_mostly;
static int tracer_enabled __read_mostly;
@@ -432,19 +433,17 @@ stop_critical_timing(unsigned long ip, unsigned long parent_ip)
}
/* start and stop critical timings used to for stoppage (in idle) */
-void start_critical_timings(void)
+static inline void start_critical_timings_tracer(void)
{
if (preempt_trace() || irq_trace())
start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
-EXPORT_SYMBOL_GPL(start_critical_timings);
-void stop_critical_timings(void)
+static inline void stop_critical_timings_tracer(void)
{
if (preempt_trace() || irq_trace())
stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
-EXPORT_SYMBOL_GPL(stop_critical_timings);
#ifdef CONFIG_IRQSOFF_TRACER
#ifdef CONFIG_PROVE_LOCKING
@@ -462,64 +461,44 @@ void time_hardirqs_off(unsigned long a0, unsigned long a1)
#else /* !CONFIG_PROVE_LOCKING */
-/*
- * Stubs:
- */
-
-void trace_softirqs_on(unsigned long ip)
-{
-}
-
-void trace_softirqs_off(unsigned long ip)
-{
-}
-
-inline void print_irqtrace_events(struct task_struct *curr)
-{
-}
-
/*
* We are only interested in hardirq on/off events:
*/
-void trace_hardirqs_on(void)
+static inline void tracer_hardirqs_on(void)
{
if (!preempt_trace() && irq_trace())
stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
-EXPORT_SYMBOL(trace_hardirqs_on);
-void trace_hardirqs_off(void)
+static inline void tracer_hardirqs_off(void)
{
if (!preempt_trace() && irq_trace())
start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
}
-EXPORT_SYMBOL(trace_hardirqs_off);
-__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+static inline void tracer_hardirqs_on_caller(unsigned long caller_addr)
{
if (!preempt_trace() && irq_trace())
stop_critical_timing(CALLER_ADDR0, caller_addr);
}
-EXPORT_SYMBOL(trace_hardirqs_on_caller);
-__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+static inline void tracer_hardirqs_off_caller(unsigned long caller_addr)
{
if (!preempt_trace() && irq_trace())
start_critical_timing(CALLER_ADDR0, caller_addr);
}
-EXPORT_SYMBOL(trace_hardirqs_off_caller);
#endif /* CONFIG_PROVE_LOCKING */
#endif /* CONFIG_IRQSOFF_TRACER */
#ifdef CONFIG_PREEMPT_TRACER
-void trace_preempt_on(unsigned long a0, unsigned long a1)
+static inline void tracer_preempt_on(unsigned long a0, unsigned long a1)
{
if (preempt_trace() && !irq_trace())
stop_critical_timing(a0, a1);
}
-void trace_preempt_off(unsigned long a0, unsigned long a1)
+static inline void tracer_preempt_off(unsigned long a0, unsigned long a1)
{
if (preempt_trace() && !irq_trace())
start_critical_timing(a0, a1);
@@ -781,3 +760,85 @@ __init static int init_irqsoff_tracer(void)
return 0;
}
core_initcall(init_irqsoff_tracer);
+#else /* IRQSOFF_TRACER || PREEMPTOFF_TRACER */
+static inline void start_critical_timings_tracer(void) { }
+static inline void stop_critical_timings_tracer(void) { }
+#endif
+
+#ifndef CONFIG_IRQSOFF_TRACER
+static inline void tracer_hardirqs_on(void) { }
+static inline void tracer_hardirqs_off(void) { }
+static inline void tracer_hardirqs_on_caller(unsigned long caller_addr) { }
+static inline void tracer_hardirqs_off_caller(unsigned long caller_addr) { }
+#endif
+
+#ifndef CONFIG_PREEMPT_TRACER
+static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
+static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
+#endif
+
+void start_critical_timings(void)
+{
+ start_critical_timings_tracer();
+}
+EXPORT_SYMBOL_GPL(start_critical_timings);
+
+void stop_critical_timings(void)
+{
+ stop_critical_timings_tracer();
+}
+EXPORT_SYMBOL_GPL(stop_critical_timings);
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
+void trace_hardirqs_on(void)
+{
+ tracer_hardirqs_on();
+}
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+void trace_hardirqs_off(void)
+{
+ tracer_hardirqs_off();
+}
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
+{
+ tracer_hardirqs_on_caller(caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+
+__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
+{
+ tracer_hardirqs_off_caller(caller_addr);
+}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+
+/*
+ * Stubs:
+ */
+
+void trace_softirqs_on(unsigned long ip)
+{
+}
+
+void trace_softirqs_off(unsigned long ip)
+{
+}
+
+inline void print_irqtrace_events(struct task_struct *curr)
+{
+}
+#endif
+
+#ifdef CONFIG_PREEMPT_TRACER
+void trace_preempt_on(unsigned long a0, unsigned long a1)
+{
+ tracer_preempt_on(a0, a1);
+}
+
+void trace_preempt_off(unsigned long a0, unsigned long a1)
+{
+ tracer_preempt_off(a0, a1);
+}
+#endif
--
2.14.1.581.gf28d330327-goog
Preempt and irq trace events can be used for tracing the start and
end of an atomic section which can be used by a trace viewer like
systrace to graphically view the start and end of an atomic section and
correlate them with latencies and scheduling issues.
This also serves as a prelude to using synthetic events or probes to
rewrite the preempt and irqsoff tracers, along with numerous benefits of
using trace events features for these events.
Cc: Steven Rostedt <[email protected]>
Cc: Peter Zilstra <[email protected]>
Cc: [email protected]
Signed-off-by: Joel Fernandes <[email protected]>
---
include/linux/ftrace.h | 3 +-
include/linux/irqflags.h | 4 +--
include/trace/events/preemptirq.h | 62 +++++++++++++++++++++++++++++++++++++++
kernel/trace/Kconfig | 9 ++++++
kernel/trace/Makefile | 1 +
kernel/trace/trace_irqsoff.c | 57 ++++++++++++++++++++++++++++++++++-
6 files changed, 132 insertions(+), 4 deletions(-)
create mode 100644 include/trace/events/preemptirq.h
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 6383115e9d2c..5790ba7a85bd 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -742,7 +742,8 @@ static inline unsigned long get_lock_parent_ip(void)
static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
#endif
-#ifdef CONFIG_PREEMPT_TRACER
+#if defined(CONFIG_PREEMPT_TRACER) || \
+ (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
extern void trace_preempt_on(unsigned long a0, unsigned long a1);
extern void trace_preempt_off(unsigned long a0, unsigned long a1);
#else
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 5dd1272d1ab2..6ad6732a4e98 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -44,8 +44,8 @@
# define INIT_TRACE_IRQFLAGS
#endif
-#if defined(CONFIG_IRQSOFF_TRACER) || \
- defined(CONFIG_PREEMPT_TRACER)
+#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER) || \
+ defined(CONFIG_PREEMPTIRQ_EVENTS)
extern void stop_critical_timings(void);
extern void start_critical_timings(void);
#else
diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
new file mode 100644
index 000000000000..601935e32cd1
--- /dev/null
+++ b/include/trace/events/preemptirq.h
@@ -0,0 +1,62 @@
+#ifdef CONFIG_PREEMPTIRQ_EVENTS
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM preemptirq
+
+#if !defined(_TRACE_PREEMPTIRQ_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_PREEMPTIRQ_H
+
+#include <linux/ktime.h>
+#include <linux/tracepoint.h>
+#include <linux/string.h>
+#include <asm/sections.h>
+
+DECLARE_EVENT_CLASS(preemptirq_template,
+
+ TP_PROTO(unsigned long ip, unsigned long parent_ip),
+
+ TP_ARGS(ip, parent_ip),
+
+ TP_STRUCT__entry(
+ __field(u32, caller_offs)
+ __field(u32, parent_offs)
+ ),
+
+ TP_fast_assign(
+ __entry->caller_offs = (u32)(ip - (unsigned long)_stext);
+ __entry->parent_offs = (u32)(parent_ip - (unsigned long)_stext);
+ ),
+
+ TP_printk("caller=%pF parent=%pF\n",
+ (void *)((unsigned long)(_stext) + __entry->caller_offs),
+ (void *)((unsigned long)(_stext) + __entry->parent_offs))
+);
+
+DEFINE_EVENT(preemptirq_template, irq_disable,
+ TP_PROTO(unsigned long ip, unsigned long parent_ip),
+ TP_ARGS(ip, parent_ip));
+
+DEFINE_EVENT(preemptirq_template, irq_enable,
+ TP_PROTO(unsigned long ip, unsigned long parent_ip),
+ TP_ARGS(ip, parent_ip));
+
+DEFINE_EVENT(preemptirq_template, preempt_disable,
+ TP_PROTO(unsigned long ip, unsigned long parent_ip),
+ TP_ARGS(ip, parent_ip));
+
+DEFINE_EVENT(preemptirq_template, preempt_enable,
+ TP_PROTO(unsigned long ip, unsigned long parent_ip),
+ TP_ARGS(ip, parent_ip));
+
+#endif /* _TRACE_PREEMPTIRQ_H */
+
+#include <trace/define_trace.h>
+
+#else /* !CONFIG_PREEMPTIRQ_EVENTS */
+
+#define trace_irq_enable(...)
+#define trace_irq_disable(...)
+#define trace_preempt_enable(...)
+#define trace_preempt_disable(...)
+
+#endif
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 434c840e2d82..420666152de8 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -160,6 +160,15 @@ config FUNCTION_GRAPH_TRACER
address on the current task structure into a stack of calls.
+config PREEMPTIRQ_EVENTS
+ bool "Enable trace events for preempt and irq disable/enable"
+ select TRACE_IRQFLAGS
+ default n
+ help
+ Enable tracing of disable and enable events for preemption and irqs.
+ For tracing preempt disable/enable events, CONFIG_DEBUG_PREEMPT must
+ be enabled.
+
config IRQSOFF_TRACER
bool "Interrupts-off Latency Tracer"
default n
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 90f2701d92a7..9f62eee61f14 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_TRACING) += trace_printk.o
obj-$(CONFIG_TRACING_MAP) += tracing_map.o
obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
+obj-$(CONFIG_PREEMPTIRQ_EVENTS) += trace_irqsoff.o
obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 26c688740742..361a17f83c4e 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -16,6 +16,9 @@
#include "trace.h"
+#define CREATE_TRACE_POINTS
+#include <trace/events/preemptirq.h>
+
#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
static struct trace_array *irqsoff_trace __read_mostly;
static int tracer_enabled __read_mostly;
@@ -777,14 +780,29 @@ static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
#endif
+static DEFINE_PER_CPU(int, tracing_irq_cpu);
+static DEFINE_PER_CPU(int, tracing_preempt_cpu);
+
void start_critical_timings(void)
{
+ if (this_cpu_read(tracing_preempt_cpu))
+ trace_preempt_enable(CALLER_ADDR0, CALLER_ADDR1);
+
+ if (this_cpu_read(tracing_irq_cpu))
+ trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
+
start_critical_timings_tracer();
}
EXPORT_SYMBOL_GPL(start_critical_timings);
void stop_critical_timings(void)
{
+ if (this_cpu_read(tracing_preempt_cpu))
+ trace_preempt_disable(CALLER_ADDR0, CALLER_ADDR1);
+
+ if (this_cpu_read(tracing_irq_cpu))
+ trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
+
stop_critical_timings_tracer();
}
EXPORT_SYMBOL_GPL(stop_critical_timings);
@@ -792,24 +810,48 @@ EXPORT_SYMBOL_GPL(stop_critical_timings);
#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
void trace_hardirqs_on(void)
{
+ if (!this_cpu_read(tracing_irq_cpu))
+ return;
+
+ trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
tracer_hardirqs_on();
+
+ this_cpu_write(tracing_irq_cpu, 0);
}
EXPORT_SYMBOL(trace_hardirqs_on);
void trace_hardirqs_off(void)
{
+ if (this_cpu_read(tracing_irq_cpu))
+ return;
+
+ this_cpu_write(tracing_irq_cpu, 1);
+
+ trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
tracer_hardirqs_off();
}
EXPORT_SYMBOL(trace_hardirqs_off);
__visible void trace_hardirqs_on_caller(unsigned long caller_addr)
{
+ if (!this_cpu_read(tracing_irq_cpu))
+ return;
+
+ trace_irq_enable(CALLER_ADDR0, caller_addr);
tracer_hardirqs_on_caller(caller_addr);
+
+ this_cpu_write(tracing_irq_cpu, 0);
}
EXPORT_SYMBOL(trace_hardirqs_on_caller);
__visible void trace_hardirqs_off_caller(unsigned long caller_addr)
{
+ if (this_cpu_read(tracing_irq_cpu))
+ return;
+
+ this_cpu_write(tracing_irq_cpu, 1);
+
+ trace_irq_disable(CALLER_ADDR0, caller_addr);
tracer_hardirqs_off_caller(caller_addr);
}
EXPORT_SYMBOL(trace_hardirqs_off_caller);
@@ -831,14 +873,27 @@ inline void print_irqtrace_events(struct task_struct *curr)
}
#endif
-#ifdef CONFIG_PREEMPT_TRACER
+#if defined(CONFIG_PREEMPT_TRACER) || \
+ (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
void trace_preempt_on(unsigned long a0, unsigned long a1)
{
+ if (!this_cpu_read(tracing_preempt_cpu))
+ return;
+
+ trace_preempt_enable(a0, a1);
tracer_preempt_on(a0, a1);
+
+ this_cpu_write(tracing_preempt_cpu, 0);
}
void trace_preempt_off(unsigned long a0, unsigned long a1)
{
+ if (this_cpu_read(tracing_preempt_cpu))
+ return;
+
+ this_cpu_write(tracing_preempt_cpu, 1);
+
+ trace_preempt_disable(a0, a1);
tracer_preempt_off(a0, a1);
}
#endif
--
2.14.1.581.gf28d330327-goog
On Tue, 12 Sep 2017 11:11:09 -0700
Joel Fernandes <[email protected]> wrote:
> Preempt and irq trace events can be used for tracing the start and
> end of an atomic section which can be used by a trace viewer like
> systrace to graphically view the start and end of an atomic section and
> correlate them with latencies and scheduling issues.
>
> This also serves as a prelude to using synthetic events or probes to
> rewrite the preempt and irqsoff tracers, along with numerous benefits of
> using trace events features for these events.
>
> Cc: Steven Rostedt <[email protected]>
> Cc: Peter Zilstra <[email protected]>
> Cc: [email protected]
> Signed-off-by: Joel Fernandes <[email protected]>
> ---
> include/linux/ftrace.h | 3 +-
> include/linux/irqflags.h | 4 +--
> include/trace/events/preemptirq.h | 62 +++++++++++++++++++++++++++++++++++++++
> kernel/trace/Kconfig | 9 ++++++
> kernel/trace/Makefile | 1 +
> kernel/trace/trace_irqsoff.c | 57 ++++++++++++++++++++++++++++++++++-
> 6 files changed, 132 insertions(+), 4 deletions(-)
> create mode 100644 include/trace/events/preemptirq.h
>
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index 6383115e9d2c..5790ba7a85bd 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -742,7 +742,8 @@ static inline unsigned long get_lock_parent_ip(void)
> static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
> #endif
>
> -#ifdef CONFIG_PREEMPT_TRACER
> +#if defined(CONFIG_PREEMPT_TRACER) || \
> + (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
> extern void trace_preempt_on(unsigned long a0, unsigned long a1);
> extern void trace_preempt_off(unsigned long a0, unsigned long a1);
> #else
> diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
> index 5dd1272d1ab2..6ad6732a4e98 100644
> --- a/include/linux/irqflags.h
> +++ b/include/linux/irqflags.h
> @@ -44,8 +44,8 @@
> # define INIT_TRACE_IRQFLAGS
> #endif
>
> -#if defined(CONFIG_IRQSOFF_TRACER) || \
> - defined(CONFIG_PREEMPT_TRACER)
> +#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER) || \
> + defined(CONFIG_PREEMPTIRQ_EVENTS)
> extern void stop_critical_timings(void);
> extern void start_critical_timings(void);
> #else
> diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
> new file mode 100644
> index 000000000000..601935e32cd1
> --- /dev/null
> +++ b/include/trace/events/preemptirq.h
> @@ -0,0 +1,62 @@
> +#ifdef CONFIG_PREEMPTIRQ_EVENTS
> +
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM preemptirq
> +
> +#if !defined(_TRACE_PREEMPTIRQ_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_PREEMPTIRQ_H
> +
> +#include <linux/ktime.h>
> +#include <linux/tracepoint.h>
> +#include <linux/string.h>
> +#include <asm/sections.h>
> +
> +DECLARE_EVENT_CLASS(preemptirq_template,
> +
> + TP_PROTO(unsigned long ip, unsigned long parent_ip),
> +
> + TP_ARGS(ip, parent_ip),
> +
> + TP_STRUCT__entry(
> + __field(u32, caller_offs)
> + __field(u32, parent_offs)
> + ),
> +
> + TP_fast_assign(
> + __entry->caller_offs = (u32)(ip - (unsigned long)_stext);
> + __entry->parent_offs = (u32)(parent_ip - (unsigned long)_stext);
> + ),
> +
> + TP_printk("caller=%pF parent=%pF\n",
No '\n', otherwise you add a lot of whitespace to the trace:
====
<idle>-0 [002] d..1 252.533022: preempt_enable: caller=cpuidle_enter_state+0xfe/0x3a0 parent=cpuidle_enter+0x17/0x20
rcu_preempt-8 [002] ...1 252.533063: preempt_enable: caller=schedule+0x4a/0x90 parent=schedule+0x4a/0x90
rcu_preempt-8 [002] d..1 252.533065: preempt_disable: caller=_raw_spin_lock_irqsave+0x2f/0x60 parent=lock_timer_base+0x81/0xa0
rcu_preempt-8 [002] ...1 252.533066: preempt_enable: caller=_raw_spin_unlock_irqrestore+0x4a/0x80 parent=try_to_del_timer_sync+0x44/0x60
rcu_preempt-8 [002] d..1 252.533067: preempt_disable: caller=_raw_spin_lock_irqsave+0x2f/0x60 parent=prepare_to_swait+0x22/0x70
rcu_preempt-8 [002] ...1 252.533067: preempt_enable: caller=_raw_spin_unlock_irqrestore+0x4a/0x80 parent=prepare_to_swait+0x63/0x70
====
> + (void *)((unsigned long)(_stext) + __entry->caller_offs),
> + (void *)((unsigned long)(_stext) + __entry->parent_offs))
> +);
> +
> +DEFINE_EVENT(preemptirq_template, irq_disable,
> + TP_PROTO(unsigned long ip, unsigned long parent_ip),
> + TP_ARGS(ip, parent_ip));
> +
> +DEFINE_EVENT(preemptirq_template, irq_enable,
> + TP_PROTO(unsigned long ip, unsigned long parent_ip),
> + TP_ARGS(ip, parent_ip));
> +
> +DEFINE_EVENT(preemptirq_template, preempt_disable,
> + TP_PROTO(unsigned long ip, unsigned long parent_ip),
> + TP_ARGS(ip, parent_ip));
> +
> +DEFINE_EVENT(preemptirq_template, preempt_enable,
> + TP_PROTO(unsigned long ip, unsigned long parent_ip),
> + TP_ARGS(ip, parent_ip));
> +
> +#endif /* _TRACE_PREEMPTIRQ_H */
> +
> +#include <trace/define_trace.h>
> +
> +#else /* !CONFIG_PREEMPTIRQ_EVENTS */
> +
> +#define trace_irq_enable(...)
> +#define trace_irq_disable(...)
> +#define trace_preempt_enable(...)
> +#define trace_preempt_disable(...)
> +
> +#endif
> diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
> index 434c840e2d82..420666152de8 100644
> --- a/kernel/trace/Kconfig
> +++ b/kernel/trace/Kconfig
> @@ -160,6 +160,15 @@ config FUNCTION_GRAPH_TRACER
> address on the current task structure into a stack of calls.
>
>
> +config PREEMPTIRQ_EVENTS
> + bool "Enable trace events for preempt and irq disable/enable"
> + select TRACE_IRQFLAGS
> + default n
> + help
> + Enable tracing of disable and enable events for preemption and irqs.
> + For tracing preempt disable/enable events, CONFIG_DEBUG_PREEMPT must
> + be enabled.
> +
> config IRQSOFF_TRACER
> bool "Interrupts-off Latency Tracer"
> default n
> diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
> index 90f2701d92a7..9f62eee61f14 100644
> --- a/kernel/trace/Makefile
> +++ b/kernel/trace/Makefile
> @@ -34,6 +34,7 @@ obj-$(CONFIG_TRACING) += trace_printk.o
> obj-$(CONFIG_TRACING_MAP) += tracing_map.o
> obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o
> obj-$(CONFIG_FUNCTION_TRACER) += trace_functions.o
> +obj-$(CONFIG_PREEMPTIRQ_EVENTS) += trace_irqsoff.o
> obj-$(CONFIG_IRQSOFF_TRACER) += trace_irqsoff.o
> obj-$(CONFIG_PREEMPT_TRACER) += trace_irqsoff.o
> obj-$(CONFIG_SCHED_TRACER) += trace_sched_wakeup.o
> diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
> index 26c688740742..361a17f83c4e 100644
> --- a/kernel/trace/trace_irqsoff.c
> +++ b/kernel/trace/trace_irqsoff.c
> @@ -16,6 +16,9 @@
>
> #include "trace.h"
>
> +#define CREATE_TRACE_POINTS
> +#include <trace/events/preemptirq.h>
> +
> #if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER)
> static struct trace_array *irqsoff_trace __read_mostly;
> static int tracer_enabled __read_mostly;
> @@ -777,14 +780,29 @@ static inline void tracer_preempt_on(unsigned long a0, unsigned long a1) { }
> static inline void tracer_preempt_off(unsigned long a0, unsigned long a1) { }
> #endif
>
> +static DEFINE_PER_CPU(int, tracing_irq_cpu);
> +static DEFINE_PER_CPU(int, tracing_preempt_cpu);
> +
> void start_critical_timings(void)
> {
> + if (this_cpu_read(tracing_preempt_cpu))
> + trace_preempt_enable(CALLER_ADDR0, CALLER_ADDR1);
> +
> + if (this_cpu_read(tracing_irq_cpu))
> + trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
> +
> start_critical_timings_tracer();
> }
> EXPORT_SYMBOL_GPL(start_critical_timings);
>
> void stop_critical_timings(void)
> {
> + if (this_cpu_read(tracing_preempt_cpu))
> + trace_preempt_disable(CALLER_ADDR0, CALLER_ADDR1);
> +
> + if (this_cpu_read(tracing_irq_cpu))
> + trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
> +
> stop_critical_timings_tracer();
> }
> EXPORT_SYMBOL_GPL(stop_critical_timings);
> @@ -792,24 +810,48 @@ EXPORT_SYMBOL_GPL(stop_critical_timings);
> #if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
> void trace_hardirqs_on(void)
> {
> + if (!this_cpu_read(tracing_irq_cpu))
> + return;
> +
> + trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
> tracer_hardirqs_on();
> +
> + this_cpu_write(tracing_irq_cpu, 0);
> }
> EXPORT_SYMBOL(trace_hardirqs_on);
>
> void trace_hardirqs_off(void)
> {
> + if (this_cpu_read(tracing_irq_cpu))
> + return;
> +
> + this_cpu_write(tracing_irq_cpu, 1);
> +
> + trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
> tracer_hardirqs_off();
> }
> EXPORT_SYMBOL(trace_hardirqs_off);
>
> __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
> {
> + if (!this_cpu_read(tracing_irq_cpu))
> + return;
> +
> + trace_irq_enable(CALLER_ADDR0, caller_addr);
> tracer_hardirqs_on_caller(caller_addr);
> +
> + this_cpu_write(tracing_irq_cpu, 0);
> }
> EXPORT_SYMBOL(trace_hardirqs_on_caller);
>
> __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
> {
> + if (this_cpu_read(tracing_irq_cpu))
> + return;
> +
> + this_cpu_write(tracing_irq_cpu, 1);
> +
> + trace_irq_disable(CALLER_ADDR0, caller_addr);
> tracer_hardirqs_off_caller(caller_addr);
> }
> EXPORT_SYMBOL(trace_hardirqs_off_caller);
> @@ -831,14 +873,27 @@ inline void print_irqtrace_events(struct task_struct *curr)
> }
> #endif
>
> -#ifdef CONFIG_PREEMPT_TRACER
> +#if defined(CONFIG_PREEMPT_TRACER) || \
> + (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
> void trace_preempt_on(unsigned long a0, unsigned long a1)
> {
> + if (!this_cpu_read(tracing_preempt_cpu))
> + return;
> +
> + trace_preempt_enable(a0, a1);
> tracer_preempt_on(a0, a1);
> +
> + this_cpu_write(tracing_preempt_cpu, 0);
> }
>
> void trace_preempt_off(unsigned long a0, unsigned long a1)
> {
> + if (this_cpu_read(tracing_preempt_cpu))
> + return;
> +
> + this_cpu_write(tracing_preempt_cpu, 1);
> +
> + trace_preempt_disable(a0, a1);
> tracer_preempt_off(a0, a1);
> }
> #endif
Need to fold in the following patch as well. Otherwise RCU may have
issues (run with lockdep enabled and you'll see all the splats).
-- Steve
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 361a17f..7dcb431 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -786,10 +786,10 @@ static DEFINE_PER_CPU(int, tracing_preempt_cpu);
void start_critical_timings(void)
{
if (this_cpu_read(tracing_preempt_cpu))
- trace_preempt_enable(CALLER_ADDR0, CALLER_ADDR1);
+ trace_preempt_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
if (this_cpu_read(tracing_irq_cpu))
- trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
+ trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
start_critical_timings_tracer();
}
@@ -798,10 +798,10 @@ EXPORT_SYMBOL_GPL(start_critical_timings);
void stop_critical_timings(void)
{
if (this_cpu_read(tracing_preempt_cpu))
- trace_preempt_disable(CALLER_ADDR0, CALLER_ADDR1);
+ trace_preempt_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
if (this_cpu_read(tracing_irq_cpu))
- trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
+ trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
stop_critical_timings_tracer();
}
@@ -813,7 +813,7 @@ void trace_hardirqs_on(void)
if (!this_cpu_read(tracing_irq_cpu))
return;
- trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
+ trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
tracer_hardirqs_on();
this_cpu_write(tracing_irq_cpu, 0);
@@ -827,7 +827,7 @@ void trace_hardirqs_off(void)
this_cpu_write(tracing_irq_cpu, 1);
- trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
+ trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
tracer_hardirqs_off();
}
EXPORT_SYMBOL(trace_hardirqs_off);
@@ -837,7 +837,7 @@ __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
if (!this_cpu_read(tracing_irq_cpu))
return;
- trace_irq_enable(CALLER_ADDR0, caller_addr);
+ trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
tracer_hardirqs_on_caller(caller_addr);
this_cpu_write(tracing_irq_cpu, 0);
@@ -851,9 +851,9 @@ __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
this_cpu_write(tracing_irq_cpu, 1);
- trace_irq_disable(CALLER_ADDR0, caller_addr);
- tracer_hardirqs_off_caller(caller_addr);
-}
+ trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
+ tracer_hardirqs_off_caller(caller_addr);}
+
EXPORT_SYMBOL(trace_hardirqs_off_caller);
/*
@@ -880,7 +880,7 @@ void trace_preempt_on(unsigned long a0, unsigned long a1)
if (!this_cpu_read(tracing_preempt_cpu))
return;
- trace_preempt_enable(a0, a1);
+ trace_preempt_enable_rcuidle(a0, a1);
tracer_preempt_on(a0, a1);
this_cpu_write(tracing_preempt_cpu, 0);
@@ -893,7 +893,7 @@ void trace_preempt_off(unsigned long a0, unsigned long a1)
this_cpu_write(tracing_preempt_cpu, 1);
- trace_preempt_disable(a0, a1);
+ trace_preempt_disable_rcuidle(a0, a1);
tracer_preempt_off(a0, a1);
}
#endif
On Wed, Sep 20, 2017 at 11:23 AM, Steven Rostedt <[email protected]> wrote:
> On Tue, 12 Sep 2017 11:11:09 -0700
> Joel Fernandes <[email protected]> wrote:
>
>> Preempt and irq trace events can be used for tracing the start and
>> end of an atomic section which can be used by a trace viewer like
>> systrace to graphically view the start and end of an atomic section and
>> correlate them with latencies and scheduling issues.
>>
>> This also serves as a prelude to using synthetic events or probes to
>> rewrite the preempt and irqsoff tracers, along with numerous benefits of
>> using trace events features for these events.
>>
>> Cc: Steven Rostedt <[email protected]>
>> Cc: Peter Zilstra <[email protected]>
>> Cc: [email protected]
>> Signed-off-by: Joel Fernandes <[email protected]>
>> ---
>> include/linux/ftrace.h | 3 +-
>> include/linux/irqflags.h | 4 +--
>> include/trace/events/preemptirq.h | 62 +++++++++++++++++++++++++++++++++++++++
>> kernel/trace/Kconfig | 9 ++++++
>> kernel/trace/Makefile | 1 +
>> kernel/trace/trace_irqsoff.c | 57 ++++++++++++++++++++++++++++++++++-
>> 6 files changed, 132 insertions(+), 4 deletions(-)
>> create mode 100644 include/trace/events/preemptirq.h
>>
>> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
>> index 6383115e9d2c..5790ba7a85bd 100644
>> --- a/include/linux/ftrace.h
>> +++ b/include/linux/ftrace.h
>> @@ -742,7 +742,8 @@ static inline unsigned long get_lock_parent_ip(void)
>> static inline void time_hardirqs_off(unsigned long a0, unsigned long a1) { }
>> #endif
>>
>> -#ifdef CONFIG_PREEMPT_TRACER
>> +#if defined(CONFIG_PREEMPT_TRACER) || \
>> + (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
>> extern void trace_preempt_on(unsigned long a0, unsigned long a1);
>> extern void trace_preempt_off(unsigned long a0, unsigned long a1);
>> #else
>> diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
>> index 5dd1272d1ab2..6ad6732a4e98 100644
>> --- a/include/linux/irqflags.h
>> +++ b/include/linux/irqflags.h
>> @@ -44,8 +44,8 @@
>> # define INIT_TRACE_IRQFLAGS
>> #endif
>>
>> -#if defined(CONFIG_IRQSOFF_TRACER) || \
>> - defined(CONFIG_PREEMPT_TRACER)
>> +#if defined(CONFIG_IRQSOFF_TRACER) || defined(CONFIG_PREEMPT_TRACER) || \
>> + defined(CONFIG_PREEMPTIRQ_EVENTS)
>> extern void stop_critical_timings(void);
>> extern void start_critical_timings(void);
>> #else
>> diff --git a/include/trace/events/preemptirq.h b/include/trace/events/preemptirq.h
>> new file mode 100644
>> index 000000000000..601935e32cd1
>> --- /dev/null
>> +++ b/include/trace/events/preemptirq.h
>> @@ -0,0 +1,62 @@
>> +#ifdef CONFIG_PREEMPTIRQ_EVENTS
>> +
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM preemptirq
>> +
>> +#if !defined(_TRACE_PREEMPTIRQ_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_PREEMPTIRQ_H
>> +
>> +#include <linux/ktime.h>
>> +#include <linux/tracepoint.h>
>> +#include <linux/string.h>
>> +#include <asm/sections.h>
>> +
>> +DECLARE_EVENT_CLASS(preemptirq_template,
>> +
>> + TP_PROTO(unsigned long ip, unsigned long parent_ip),
>> +
>> + TP_ARGS(ip, parent_ip),
>> +
>> + TP_STRUCT__entry(
>> + __field(u32, caller_offs)
>> + __field(u32, parent_offs)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->caller_offs = (u32)(ip - (unsigned long)_stext);
>> + __entry->parent_offs = (u32)(parent_ip - (unsigned long)_stext);
>> + ),
>> +
>> + TP_printk("caller=%pF parent=%pF\n",
>
> No '\n', otherwise you add a lot of whitespace to the trace:
>
Sure will fix, thanks.
[..]
>> EXPORT_SYMBOL_GPL(stop_critical_timings);
>> @@ -792,24 +810,48 @@ EXPORT_SYMBOL_GPL(stop_critical_timings);
>> #if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PROVE_LOCKING)
>> void trace_hardirqs_on(void)
>> {
>> + if (!this_cpu_read(tracing_irq_cpu))
>> + return;
>> +
>> + trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
>> tracer_hardirqs_on();
>> +
>> + this_cpu_write(tracing_irq_cpu, 0);
>> }
>> EXPORT_SYMBOL(trace_hardirqs_on);
>>
>> void trace_hardirqs_off(void)
>> {
>> + if (this_cpu_read(tracing_irq_cpu))
>> + return;
>> +
>> + this_cpu_write(tracing_irq_cpu, 1);
>> +
>> + trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
>> tracer_hardirqs_off();
>> }
>> EXPORT_SYMBOL(trace_hardirqs_off);
>>
>> __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
>> {
>> + if (!this_cpu_read(tracing_irq_cpu))
>> + return;
>> +
>> + trace_irq_enable(CALLER_ADDR0, caller_addr);
>> tracer_hardirqs_on_caller(caller_addr);
>> +
>> + this_cpu_write(tracing_irq_cpu, 0);
>> }
>> EXPORT_SYMBOL(trace_hardirqs_on_caller);
>>
>> __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
>> {
>> + if (this_cpu_read(tracing_irq_cpu))
>> + return;
>> +
>> + this_cpu_write(tracing_irq_cpu, 1);
>> +
>> + trace_irq_disable(CALLER_ADDR0, caller_addr);
>> tracer_hardirqs_off_caller(caller_addr);
>> }
>> EXPORT_SYMBOL(trace_hardirqs_off_caller);
>> @@ -831,14 +873,27 @@ inline void print_irqtrace_events(struct task_struct *curr)
>> }
>> #endif
>>
>> -#ifdef CONFIG_PREEMPT_TRACER
>> +#if defined(CONFIG_PREEMPT_TRACER) || \
>> + (defined(CONFIG_DEBUG_PREEMPT) && defined(CONFIG_PREEMPTIRQ_EVENTS))
>> void trace_preempt_on(unsigned long a0, unsigned long a1)
>> {
>> + if (!this_cpu_read(tracing_preempt_cpu))
>> + return;
>> +
>> + trace_preempt_enable(a0, a1);
>> tracer_preempt_on(a0, a1);
>> +
>> + this_cpu_write(tracing_preempt_cpu, 0);
>> }
>>
>> void trace_preempt_off(unsigned long a0, unsigned long a1)
>> {
>> + if (this_cpu_read(tracing_preempt_cpu))
>> + return;
>> +
>> + this_cpu_write(tracing_preempt_cpu, 1);
>> +
>> + trace_preempt_disable(a0, a1);
>> tracer_preempt_off(a0, a1);
>> }
>> #endif
>
> Need to fold in the following patch as well. Otherwise RCU may have
> issues (run with lockdep enabled and you'll see all the splats).
Ok, will fix, thanks!
>
> -- Steve
>
> diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
> index 361a17f..7dcb431 100644
> --- a/kernel/trace/trace_irqsoff.c
> +++ b/kernel/trace/trace_irqsoff.c
> @@ -786,10 +786,10 @@ static DEFINE_PER_CPU(int, tracing_preempt_cpu);
> void start_critical_timings(void)
> {
> if (this_cpu_read(tracing_preempt_cpu))
> - trace_preempt_enable(CALLER_ADDR0, CALLER_ADDR1);
> + trace_preempt_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
>
> if (this_cpu_read(tracing_irq_cpu))
> - trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
> + trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
>
> start_critical_timings_tracer();
> }
> @@ -798,10 +798,10 @@ EXPORT_SYMBOL_GPL(start_critical_timings);
> void stop_critical_timings(void)
> {
> if (this_cpu_read(tracing_preempt_cpu))
> - trace_preempt_disable(CALLER_ADDR0, CALLER_ADDR1);
> + trace_preempt_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
>
> if (this_cpu_read(tracing_irq_cpu))
> - trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
> + trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
>
> stop_critical_timings_tracer();
> }
> @@ -813,7 +813,7 @@ void trace_hardirqs_on(void)
> if (!this_cpu_read(tracing_irq_cpu))
> return;
>
> - trace_irq_enable(CALLER_ADDR0, CALLER_ADDR1);
> + trace_irq_enable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
> tracer_hardirqs_on();
>
> this_cpu_write(tracing_irq_cpu, 0);
> @@ -827,7 +827,7 @@ void trace_hardirqs_off(void)
>
> this_cpu_write(tracing_irq_cpu, 1);
>
> - trace_irq_disable(CALLER_ADDR0, CALLER_ADDR1);
> + trace_irq_disable_rcuidle(CALLER_ADDR0, CALLER_ADDR1);
> tracer_hardirqs_off();
> }
> EXPORT_SYMBOL(trace_hardirqs_off);
> @@ -837,7 +837,7 @@ __visible void trace_hardirqs_on_caller(unsigned long caller_addr)
> if (!this_cpu_read(tracing_irq_cpu))
> return;
>
> - trace_irq_enable(CALLER_ADDR0, caller_addr);
> + trace_irq_enable_rcuidle(CALLER_ADDR0, caller_addr);
> tracer_hardirqs_on_caller(caller_addr);
>
> this_cpu_write(tracing_irq_cpu, 0);
> @@ -851,9 +851,9 @@ __visible void trace_hardirqs_off_caller(unsigned long caller_addr)
>
> this_cpu_write(tracing_irq_cpu, 1);
>
> - trace_irq_disable(CALLER_ADDR0, caller_addr);
> - tracer_hardirqs_off_caller(caller_addr);
> -}
> + trace_irq_disable_rcuidle(CALLER_ADDR0, caller_addr);
> + tracer_hardirqs_off_caller(caller_addr);}
> +
> EXPORT_SYMBOL(trace_hardirqs_off_caller);
>
> /*
> @@ -880,7 +880,7 @@ void trace_preempt_on(unsigned long a0, unsigned long a1)
> if (!this_cpu_read(tracing_preempt_cpu))
> return;
>
> - trace_preempt_enable(a0, a1);
> + trace_preempt_enable_rcuidle(a0, a1);
> tracer_preempt_on(a0, a1);
>
> this_cpu_write(tracing_preempt_cpu, 0);
> @@ -893,7 +893,7 @@ void trace_preempt_off(unsigned long a0, unsigned long a1)
>
> this_cpu_write(tracing_preempt_cpu, 1);
>
> - trace_preempt_disable(a0, a1);
> + trace_preempt_disable_rcuidle(a0, a1);
> tracer_preempt_off(a0, a1);
> }
> #endif
>
> --
> You received this message because you are subscribed to the Google Groups "kernel-team" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected].
>