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authorSteven Rostedt <srostedt@redhat.com>2008-05-12 21:20:42 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-05-23 20:32:54 +0200
commit6cd8a4bb2f97527a9ceb30bc77ea4e959c6a95e3 (patch)
tree845af8f3c7f8956b4f3591759a0d67248af243a2 /arch
parent81d68a96a39844853b37f20cc8282d9b65b78ef3 (diff)
ftrace: trace preempt off critical timings
Add preempt off timings. A lot of kernel core code is taken from the RT patch latency trace that was written by Ingo Molnar. This adds "preemptoff" and "preemptirqsoff" to /debugfs/tracing/available_tracers Now instead of just tracing irqs off, preemption off can be selected to be recorded. When this is selected, it shares the same files as irqs off timings. One can either trace preemption off, irqs off, or one or the other off. By echoing "preemptoff" into /debugfs/tracing/current_tracer, recording of preempt off only is performed. "irqsoff" will only record the time irqs are disabled, but "preemptirqsoff" will take the total time irqs or preemption are disabled. Runtime switching of these options is now supported by simpling echoing in the appropriate trace name into /debugfs/tracing/current_tracer. 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 'arch')
-rw-r--r--arch/x86/kernel/process_32.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index f8476dfbb60..a30aa1f2607 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -185,7 +185,10 @@ void cpu_idle(void)
local_irq_disable();
__get_cpu_var(irq_stat).idle_timestamp = jiffies;
+ /* Don't trace irqs off for idle */
+ stop_critical_timings();
idle();
+ start_critical_timings();
}
tick_nohz_restart_sched_tick();
preempt_enable_no_resched();