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| author | Steven Rostedt <srostedt@redhat.com> | 2008-05-12 21:20:42 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2008-05-23 20:32:27 +0200 |
| commit | 35e8e302e5d6e32675df2fc1dd3a53dfa6630dc1 (patch) | |
| tree | 5b5b503666d882bbb4d805b7b20b4f3b11d2c40e /kernel/trace/Kconfig | |
| parent | 1b29b01887e6032dcaf818c14999c7a39593b4e7 (diff) | |
| download | lwn-35e8e302e5d6e32675df2fc1dd3a53dfa6630dc1.tar.gz lwn-35e8e302e5d6e32675df2fc1dd3a53dfa6630dc1.zip | |
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/Kconfig | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 1399f372b5dc..5d6aa92866cd 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. + |