mirror of
https://github.com/torvalds/linux.git
synced 2024-11-16 00:52:01 +00:00
136 lines
3.8 KiB
Plaintext
136 lines
3.8 KiB
Plaintext
#
|
|
# Architectures that offer an FTRACE implementation should select HAVE_FTRACE:
|
|
#
|
|
config HAVE_FTRACE
|
|
bool
|
|
|
|
config HAVE_DYNAMIC_FTRACE
|
|
bool
|
|
|
|
config TRACER_MAX_TRACE
|
|
bool
|
|
|
|
config TRACING
|
|
bool
|
|
select DEBUG_FS
|
|
select STACKTRACE
|
|
|
|
config FTRACE
|
|
bool "Kernel Function Tracer"
|
|
depends on 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
|
|
instruction to the beginning of every kernel function, which NOP
|
|
sequence is then dynamically patched into a tracer call when
|
|
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 IRQSOFF_TRACER
|
|
bool "Interrupts-off Latency Tracer"
|
|
default n
|
|
depends on TRACE_IRQFLAGS_SUPPORT
|
|
depends on GENERIC_TIME
|
|
depends on HAVE_FTRACE
|
|
select TRACE_IRQFLAGS
|
|
select TRACING
|
|
select TRACER_MAX_TRACE
|
|
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 > /debugfs/tracing/tracing_max_latency
|
|
|
|
(Note that kernel size and overhead increases with this option
|
|
enabled. This option and the preempt-off timing option can be
|
|
used together or separately.)
|
|
|
|
config PREEMPT_TRACER
|
|
bool "Preemption-off Latency Tracer"
|
|
default n
|
|
depends on GENERIC_TIME
|
|
depends on PREEMPT
|
|
depends on HAVE_FTRACE
|
|
select TRACING
|
|
select TRACER_MAX_TRACE
|
|
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 > /debugfs/tracing/tracing_max_latency
|
|
|
|
(Note that kernel size and overhead increases with this option
|
|
enabled. This option and the irqs-off timing option can be
|
|
used together or separately.)
|
|
|
|
config SYSPROF_TRACER
|
|
bool "Sysprof Tracer"
|
|
depends on X86
|
|
select TRACING
|
|
help
|
|
This tracer provides the trace needed by the 'Sysprof' userspace
|
|
tool.
|
|
|
|
config SCHED_TRACER
|
|
bool "Scheduling Latency Tracer"
|
|
depends on HAVE_FTRACE
|
|
select TRACING
|
|
select CONTEXT_SWITCH_TRACER
|
|
select TRACER_MAX_TRACE
|
|
help
|
|
This tracer tracks the latency of the highest priority task
|
|
to be scheduled in, starting from the point it has woken up.
|
|
|
|
config CONTEXT_SWITCH_TRACER
|
|
bool "Trace process context switches"
|
|
depends on HAVE_FTRACE
|
|
select TRACING
|
|
select MARKERS
|
|
help
|
|
This tracer gets called from the context switch and records
|
|
all switching of tasks.
|
|
|
|
config DYNAMIC_FTRACE
|
|
bool "enable/disable ftrace tracepoints dynamically"
|
|
depends on FTRACE
|
|
depends on HAVE_DYNAMIC_FTRACE
|
|
default y
|
|
help
|
|
This option will modify all the calls to ftrace dynamically
|
|
(will patch them out of the binary image and replaces them
|
|
with a No-Op instruction) as they are called. A table is
|
|
created to dynamically enable them again.
|
|
|
|
This way a CONFIG_FTRACE kernel is slightly larger, but otherwise
|
|
has native performance as long as no tracing is active.
|
|
|
|
The changes to the code are done by a kernel thread that
|
|
wakes up once a second and checks to see if any ftrace calls
|
|
were made. If so, it runs stop_machine (stops all CPUS)
|
|
and modifies the code to jump over the call to ftrace.
|
|
|
|
config FTRACE_SELFTEST
|
|
bool
|
|
|
|
config FTRACE_STARTUP_TEST
|
|
bool "Perform a startup test on ftrace"
|
|
depends on TRACING
|
|
select FTRACE_SELFTEST
|
|
help
|
|
This option performs a series of startup tests on ftrace. On bootup
|
|
a series of tests are made to verify that the tracer is
|
|
functioning properly. It will do tests on all the configured
|
|
tracers of ftrace.
|