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authorSteven Rostedt <srostedt@redhat.com>2008-05-12 15:20:42 -0400
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 14:32:46 -0400
commit81d68a96a39844853b37f20cc8282d9b65b78ef3 (patch)
treebbc05f415930c15fb5a1004620bd77585fcec43a /include/linux/irqflags.h
parent352ad25aa4a189c667cb2af333948d34692a2d27 (diff)
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 'include/linux/irqflags.h')
-rw-r--r--include/linux/irqflags.h12
1 files changed, 10 insertions, 2 deletions
diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index e600c4e9b8c5..5b711d4e9fd9 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -12,10 +12,10 @@
12#define _LINUX_TRACE_IRQFLAGS_H 12#define _LINUX_TRACE_IRQFLAGS_H
13 13
14#ifdef CONFIG_TRACE_IRQFLAGS 14#ifdef CONFIG_TRACE_IRQFLAGS
15 extern void trace_hardirqs_on(void);
16 extern void trace_hardirqs_off(void);
17 extern void trace_softirqs_on(unsigned long ip); 15 extern void trace_softirqs_on(unsigned long ip);
18 extern void trace_softirqs_off(unsigned long ip); 16 extern void trace_softirqs_off(unsigned long ip);
17 extern void trace_hardirqs_on(void);
18 extern void trace_hardirqs_off(void);
19# define trace_hardirq_context(p) ((p)->hardirq_context) 19# define trace_hardirq_context(p) ((p)->hardirq_context)
20# define trace_softirq_context(p) ((p)->softirq_context) 20# define trace_softirq_context(p) ((p)->softirq_context)
21# define trace_hardirqs_enabled(p) ((p)->hardirqs_enabled) 21# define trace_hardirqs_enabled(p) ((p)->hardirqs_enabled)
@@ -41,6 +41,14 @@
41# define INIT_TRACE_IRQFLAGS 41# define INIT_TRACE_IRQFLAGS
42#endif 42#endif
43 43
44#ifdef CONFIG_IRQSOFF_TRACER
45 extern void stop_critical_timings(void);
46 extern void start_critical_timings(void);
47#else
48# define stop_critical_timings() do { } while (0)
49# define start_critical_timings() do { } while (0)
50#endif
51
44#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT 52#ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT
45 53
46#include <asm/irqflags.h> 54#include <asm/irqflags.h>