| # | |
| # Architectures that offer an FUNCTION_TRACER implementation should | |
| # select HAVE_FUNCTION_TRACER: | |
| # | |
| config NOP_TRACER | |
| bool | |
| config HAVE_FUNCTION_TRACER | |
| bool | |
| config HAVE_DYNAMIC_FTRACE | |
| bool | |
| config HAVE_FTRACE_MCOUNT_RECORD | |
| bool | |
| config TRACER_MAX_TRACE | |
| bool | |
| config RING_BUFFER | |
| bool | |
| config TRACING | |
| bool | |
| select DEBUG_FS | |
| select RING_BUFFER | |
| select STACKTRACE if STACKTRACE_SUPPORT | |
| select TRACEPOINTS | |
| select NOP_TRACER | |
| menu "Tracers" | |
| config FUNCTION_TRACER | |
| bool "Kernel Function Tracer" | |
| depends on HAVE_FUNCTION_TRACER | |
| depends on DEBUG_KERNEL | |
| 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 DEBUG_KERNEL | |
| 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 DEBUG_KERNEL | |
| 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 DEBUG_KERNEL | |
| 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 DEBUG_KERNEL | |
| select TRACING | |
| select MARKERS | |
| help | |
| This tracer gets called from the context switch and records | |
| all switching of tasks. | |
| config BOOT_TRACER | |
| bool "Trace boot initcalls" | |
| depends on DEBUG_KERNEL | |
| select TRACING | |
| select CONTEXT_SWITCH_TRACER | |
| help | |
| This tracer helps developers to optimize boot times: it records | |
| the timings of the initcalls and traces key events and the identity | |
| of tasks that can cause boot delays, such as context-switches. | |
| Its aim is to be parsed by the /scripts/bootgraph.pl tool to | |
| produce pretty graphics about boot inefficiencies, giving a visual | |
| representation of the delays during initcalls - but the raw | |
| /debug/tracing/trace text output is readable too. | |
| ( Note that tracing self tests can't be enabled if this tracer is | |
| selected, because the self-tests are an initcall as well and that | |
| would invalidate the boot trace. ) | |
| config STACK_TRACER | |
| bool "Trace max stack" | |
| depends on HAVE_FUNCTION_TRACER | |
| depends on DEBUG_KERNEL | |
| select FUNCTION_TRACER | |
| select STACKTRACE | |
| help | |
| This special tracer records the maximum stack footprint of the | |
| kernel and displays it in debugfs/tracing/stack_trace. | |
| This tracer works by hooking into every function call that the | |
| kernel executes, and keeping a maximum stack depth value and | |
| stack-trace saved. Because this logic has to execute in every | |
| kernel function, all the time, this option can slow down the | |
| kernel measurably and is generally intended for kernel | |
| developers only. | |
| Say N if unsure. | |
| config DYNAMIC_FTRACE | |
| bool "enable/disable ftrace tracepoints dynamically" | |
| depends on FUNCTION_TRACER | |
| depends on HAVE_DYNAMIC_FTRACE | |
| depends on DEBUG_KERNEL | |
| 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_FUNCTION_TRACER 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_MCOUNT_RECORD | |
| def_bool y | |
| depends on DYNAMIC_FTRACE | |
| depends on HAVE_FTRACE_MCOUNT_RECORD | |
| config FTRACE_SELFTEST | |
| bool | |
| config FTRACE_STARTUP_TEST | |
| bool "Perform a startup test on ftrace" | |
| depends on TRACING && DEBUG_KERNEL && !BOOT_TRACER | |
| 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. | |
| endmenu |