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| author | Steven Rostedt <srostedt@redhat.com> | 2009-09-04 14:24:40 -0400 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2009-09-04 19:42:22 -0400 |
| commit | 85bac32c4a52c592b857f2c360cc5ec93a097d70 (patch) | |
| tree | 510e516dd5fa388cb9582a2f6b055f3725fbf2c1 /kernel/trace/Kconfig | |
| parent | 62f0b3eb5cb58931a02ee4e599e19c80a171e351 (diff) | |
| download | blackbird-obmc-linux-85bac32c4a52c592b857f2c360cc5ec93a097d70.tar.gz blackbird-obmc-linux-85bac32c4a52c592b857f2c360cc5ec93a097d70.zip | |
ring-buffer: only enable ring_buffer_swap_cpu when needed
Since the ability to swap the cpu buffers adds a small overhead to
the recording of a trace, we only want to add it when needed.
Only the irqsoff and preemptoff tracers use this feature, and both are
not recommended for production kernels. This patch disables its use
when neither irqsoff nor preemptoff is configured.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 163fbfc2f39f..1ea0d1234f4a 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -62,6 +62,12 @@ config EVENT_TRACING config CONTEXT_SWITCH_TRACER bool +config RING_BUFFER_ALLOW_SWAP + bool + help + Allow the use of ring_buffer_swap_cpu. + Adds a very slight overhead to tracing when enabled. + # All tracer options should select GENERIC_TRACER. For those options that are # enabled by all tracers (context switch and event tracer) they select TRACING. # This allows those options to appear when no other tracer is selected. But the @@ -146,6 +152,7 @@ config IRQSOFF_TRACER select TRACE_IRQFLAGS select GENERIC_TRACER select TRACER_MAX_TRACE + select RING_BUFFER_ALLOW_SWAP help This option measures the time spent in irqs-off critical sections, with microsecond accuracy. @@ -167,6 +174,7 @@ config PREEMPT_TRACER depends on PREEMPT select GENERIC_TRACER select TRACER_MAX_TRACE + select RING_BUFFER_ALLOW_SWAP help This option measures the time spent in preemption off critical sections, with microsecond accuracy. |
