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authorSteven Rostedt <srostedt@redhat.com>2008-05-12 19:20:42 (GMT)
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 18:32:46 (GMT)
commit81d68a96a39844853b37f20cc8282d9b65b78ef3 (patch)
treebbc05f415930c15fb5a1004620bd77585fcec43a /kernel/lockdep.c
parent352ad25aa4a189c667cb2af333948d34692a2d27 (diff)
downloadlinux-81d68a96a39844853b37f20cc8282d9b65b78ef3.tar.xz
ftrace: trace irq disabled critical timings
This patch adds latency tracing for critical timings (how long interrupts are disabled for). "irqsoff" is added to /debugfs/tracing/available_tracers Note: tracing_max_latency also holds the max latency for irqsoff (in usecs). (default to large number so one must start latency tracing) tracing_thresh threshold (in usecs) to always print out if irqs off is detected to be longer than stated here. If irq_thresh is non-zero, then max_irq_latency is ignored. Here's an example of a trace with ftrace_enabled = 0 ======= preemption latency trace v1.1.5 on 2.6.24-rc7 Signed-off-by: Ingo Molnar <mingo@elte.hu> -------------------------------------------------------------------- latency: 100 us, #3/3, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- => started at: _spin_lock_irqsave+0x2a/0xb7 => ended at: _spin_unlock_irqrestore+0x32/0x5f _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 1d.s3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000]) swapper-0 1d.s3 100us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1d.s3 100us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f) vim:ft=help ======= And this is a trace with ftrace_enabled == 1 ======= preemption latency trace v1.1.5 on 2.6.24-rc7 -------------------------------------------------------------------- latency: 102 us, #12/12, CPU#1 | (M:rt VP:0, KP:0, SP:0 HP:0 #P:2) ----------------- | task: swapper-0 (uid:0 nice:0 policy:0 rt_prio:0) ----------------- => started at: _spin_lock_irqsave+0x2a/0xb7 => ended at: _spin_unlock_irqrestore+0x32/0x5f _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | caller \ / ||||| \ | / swapper-0 1dNs3 0us+: _spin_lock_irqsave+0x2a/0xb7 (e1000_update_stats+0x47/0x64c [e1000]) swapper-0 1dNs3 46us : e1000_read_phy_reg+0x16/0x225 [e1000] (e1000_update_stats+0x5e2/0x64c [e1000]) swapper-0 1dNs3 46us : e1000_swfw_sync_acquire+0x10/0x99 [e1000] (e1000_read_phy_reg+0x49/0x225 [e1000]) swapper-0 1dNs3 46us : e1000_get_hw_eeprom_semaphore+0x12/0xa6 [e1000] (e1000_swfw_sync_acquire+0x36/0x99 [e1000]) swapper-0 1dNs3 47us : __const_udelay+0x9/0x47 (e1000_read_phy_reg+0x116/0x225 [e1000]) swapper-0 1dNs3 47us+: __delay+0x9/0x50 (__const_udelay+0x45/0x47) swapper-0 1dNs3 97us : preempt_schedule+0xc/0x84 (__delay+0x4e/0x50) swapper-0 1dNs3 98us : e1000_swfw_sync_release+0xc/0x55 [e1000] (e1000_read_phy_reg+0x211/0x225 [e1000]) swapper-0 1dNs3 99us+: e1000_put_hw_eeprom_semaphore+0x9/0x35 [e1000] (e1000_swfw_sync_release+0x50/0x55 [e1000]) swapper-0 1dNs3 101us : _spin_unlock_irqrestore+0xe/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1dNs3 102us : _spin_unlock_irqrestore+0x32/0x5f (e1000_update_stats+0x641/0x64c [e1000]) swapper-0 1dNs3 102us : trace_hardirqs_on_caller+0x75/0x89 (_spin_unlock_irqrestore+0x32/0x5f) vim:ft=help ======= Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 81a4e4a..e219243 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -39,6 +39,7 @@
#include <linux/irqflags.h>
#include <linux/utsname.h>
#include <linux/hash.h>
+#include <linux/ftrace.h>
#include <asm/sections.h>
@@ -982,7 +983,7 @@ check_noncircular(struct lock_class *source, unsigned int depth)
return 1;
}
-#ifdef CONFIG_TRACE_IRQFLAGS
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
* Forwards and backwards subgraph searching, for the purposes of
* proving that two subgraphs can be connected by a new dependency
@@ -1680,7 +1681,7 @@ valid_state(struct task_struct *curr, struct held_lock *this,
static int mark_lock(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit new_bit);
-#ifdef CONFIG_TRACE_IRQFLAGS
+#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
/*
* print irq inversion bug:
@@ -2013,11 +2014,13 @@ void early_boot_irqs_on(void)
/*
* Hardirqs will be enabled:
*/
-void trace_hardirqs_on(void)
+void notrace trace_hardirqs_on_caller(unsigned long a0)
{
struct task_struct *curr = current;
unsigned long ip;
+ time_hardirqs_on(CALLER_ADDR0, a0);
+
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
@@ -2055,16 +2058,23 @@ void trace_hardirqs_on(void)
curr->hardirq_enable_event = ++curr->irq_events;
debug_atomic_inc(&hardirqs_on_events);
}
+EXPORT_SYMBOL(trace_hardirqs_on_caller);
+void notrace trace_hardirqs_on(void)
+{
+ trace_hardirqs_on_caller(CALLER_ADDR0);
+}
EXPORT_SYMBOL(trace_hardirqs_on);
/*
* Hardirqs were disabled:
*/
-void trace_hardirqs_off(void)
+void notrace trace_hardirqs_off_caller(unsigned long a0)
{
struct task_struct *curr = current;
+ time_hardirqs_off(CALLER_ADDR0, a0);
+
if (unlikely(!debug_locks || current->lockdep_recursion))
return;
@@ -2082,7 +2092,12 @@ void trace_hardirqs_off(void)
} else
debug_atomic_inc(&redundant_hardirqs_off);
}
+EXPORT_SYMBOL(trace_hardirqs_off_caller);
+void notrace trace_hardirqs_off(void)
+{
+ trace_hardirqs_off_caller(CALLER_ADDR0);
+}
EXPORT_SYMBOL(trace_hardirqs_off);
/*