Commit 22cffc2b authored by Steven Rostedt (Red Hat)'s avatar Steven Rostedt (Red Hat) Committed by Steven Rostedt
Browse files

tracing: Enable snapshot when any latency tracer is enabled 



The snapshot utility is extremely useful, and does not add any more
overhead in memory when another latency tracer is enabled. They use
the snapshot underneath. There's no reason to hide the snapshot file
when a latency tracer has been enabled in the kernel.

If any of the latency tracers (irq, preempt or wakeup) is enabled
then also select the snapshot facility.

Note, snapshot can be enabled without the latency tracers enabled.

Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent 873c642f

kernel/trace/Kconfig

+3 −0
Original line number Diff line number Diff line
@@ -191,6 +191,7 @@ config IRQSOFF_TRACER 
	select GENERIC_TRACER

	select TRACER_MAX_TRACE

	select RING_BUFFER_ALLOW_SWAP

	select TRACER_SNAPSHOT

	help

	  This option measures the time spent in irqs-off critical

	  sections, with microsecond accuracy.
@@ -213,6 +214,7 @@ config PREEMPT_TRACER 
	select GENERIC_TRACER

	select TRACER_MAX_TRACE

	select RING_BUFFER_ALLOW_SWAP

	select TRACER_SNAPSHOT

	help

	  This option measures the time spent in preemption-off critical

	  sections, with microsecond accuracy.
@@ -232,6 +234,7 @@ config SCHED_TRACER 
	select GENERIC_TRACER

	select CONTEXT_SWITCH_TRACER

	select TRACER_MAX_TRACE

	select TRACER_SNAPSHOT

	help

	  This tracer tracks the latency of the highest priority task

	  to be scheduled in, starting from the point it has woken up.

CRA Git | Maintained and supported by SUSTech CRA and CCSE