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build: Add IRQSOFF and PREEMPT TRACER kernel config option

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This adds the CONFIG_IRQSOFF_TRACER and the CONFIG_PREEMPT_TRACER kernel
configuration option to the OpenWrt menu. This can be used to debug
latencies in the system.
The CONFIG_PREEMPT_TRACER option needs the CONFIG_PREEMPT option which is
supposed to be used for Low-Latency Desktop and not used by many targets
in OpenWrt.

The help text is copied from the Linux kernel Kconfig.

Signed-off-by: Hauke Mehrtens <hmehrtens@maxlinear.com>
This commit is contained in:
Hauke Mehrtens
2020-12-03 18:49:12 +01:00
committed by Hauke Mehrtens
parent 47f30a566e
commit 1926ffb5ab
1 changed files with 34 additions and 0 deletions
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34
config/Config-kernel.in
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@@ -266,6 +266,40 @@ config KERNEL_FUNCTION_PROFILER
depends on KERNEL_FUNCTION_TRACER
default n
config KERNEL_IRQSOFF_TRACER
bool "Interrupts-off Latency Tracer"
depends on KERNEL_FTRACE
help
This option measures the time spent in irqs-off critical
sections, with microsecond accuracy.
The default measurement method is a maximum search, which is
disabled by default and can be runtime (re-)started
via:
echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
(Note that kernel size and overhead increase with this option
enabled. This option and the preempt-off timing option can be
used together or separately.)
config KERNEL_PREEMPT_TRACER
bool "Preemption-off Latency Tracer"
depends on KERNEL_FTRACE
help
This option measures the time spent in preemption-off critical
sections, with microsecond accuracy.
The default measurement method is a maximum search, which is
disabled by default and can be runtime (re-)started
via:
echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
(Note that kernel size and overhead increase with this option
enabled. This option and the irqs-off timing option can be
used together or separately.)
config KERNEL_DEBUG_KERNEL
bool
default n