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authorSteven Rostedt <srostedt@redhat.com>2008-05-12 21:20:42 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 20:32:27 +0200
commit35e8e302e5d6e32675df2fc1dd3a53dfa6630dc1 (patch)
tree5b5b503666d882bbb4d805b7b20b4f3b11d2c40e /kernel/trace/Kconfig
parent1b29b01887e6032dcaf818c14999c7a39593b4e7 (diff)
ftrace: add tracing of context switches
This patch adds context switch tracing, of the format of: _------=> CPU# / _-----=> irqs-off | / _----=> need-resched || / _---=> hardirq/softirq ||| / _--=> preempt-depth |||| / ||||| delay cmd pid ||||| time | pid:prio:state \ / ||||| \ | / swapper-0 1d..3 137us+: 0:140:R --> 2912:120 sshd-2912 1d..3 216us+: 2912:120:S --> 0:140 swapper-0 1d..3 261us+: 0:140:R --> 2912:120 bash-2920 0d..3 267us+: 2920:120:S --> 0:140 sshd-2912 1d..3 330us!: 2912:120:S --> 0:140 swapper-0 1d..3 2389us+: 0:140:R --> 2847:120 yum-upda-2847 1d..3 2411us!: 2847:120:S --> 0:140 swapper-0 0d..3 11089us+: 0:140:R --> 3139:120 gdm-bina-3139 0d..3 11113us!: 3139:120:S --> 0:140 swapper-0 1d..3 102328us+: 0:140:R --> 2847:120 yum-upda-2847 1d..3 102348us!: 2847:120:S --> 0:140 "sched_switch" is added to /debugfs/tracing/available_tracers [ Eugene Teo <eugeneteo@kernel.sg: remove unused tracing_sched_switch_enabled ] Signed-off-by: Steven Rostedt <srostedt@redhat.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/trace/Kconfig')
-rw-r--r--kernel/trace/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 1399f372b5d..5d6aa92866c 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -13,6 +13,7 @@ config FTRACE
depends on DEBUG_KERNEL && HAVE_FTRACE
select FRAME_POINTER
select TRACING
+ select CONTEXT_SWITCH_TRACER
help
Enable the kernel to trace every kernel function. This is done
by using a compiler feature to insert a small, 5-byte No-Operation
@@ -21,3 +22,13 @@ config FTRACE
tracing is enabled by the administrator. If it's runtime disabled
(the bootup default), then the overhead of the instructions is very
small and not measurable even in micro-benchmarks.
+
+config CONTEXT_SWITCH_TRACER
+ bool "Trace process context switches"
+ depends on DEBUG_KERNEL
+ select TRACING
+ select MARKERS
+ help
+ This tracer gets called from the context switch and records
+ all switching of tasks.
+