| # | |
| # Architectures that offer an FUNCTION_TRACER implementation should | |
| # select HAVE_FUNCTION_TRACER: | |
| # | |
| config USER_STACKTRACE_SUPPORT | |
| bool | |
| config NOP_TRACER | |
| bool | |
| config HAVE_FUNCTION_TRACER | |
| bool | |
| config HAVE_FUNCTION_GRAPH_TRACER | |
| bool | |
| config HAVE_FUNCTION_TRACE_MCOUNT_TEST | |
| bool | |
| help | |
| This gets selected when the arch tests the function_trace_stop | |
| variable at the mcount call site. Otherwise, this variable | |
| is tested by the called function. | |
| config HAVE_DYNAMIC_FTRACE | |
| bool | |
| config HAVE_FTRACE_MCOUNT_RECORD | |
| bool | |
| config HAVE_HW_BRANCH_TRACER | |
| 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 FUNCTION_GRAPH_TRACER | |
| bool "Kernel Function Graph Tracer" | |
| depends on HAVE_FUNCTION_GRAPH_TRACER | |
| depends on FUNCTION_TRACER | |
| default y | |
| help | |
| Enable the kernel to trace a function at both its return | |
| and its entry. | |
| It's first purpose is to trace the duration of functions and | |
| draw a call graph for each thread with some informations like | |
| the return value. | |
| This is done by setting the current return address on the current | |
| task structure into a stack of calls. | |
| 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 TRACE_BRANCH_PROFILING | |
| bool "Trace likely/unlikely profiler" | |
| depends on DEBUG_KERNEL | |
| select TRACING | |
| help | |
| This tracer profiles all the the likely and unlikely macros | |
| in the kernel. It will display the results in: | |
| /debugfs/tracing/profile_annotated_branch | |
| Note: this will add a significant overhead, only turn this | |
| on if you need to profile the system's use of these macros. | |
| Say N if unsure. | |
| config PROFILE_ALL_BRANCHES | |
| bool "Profile all if conditionals" | |
| depends on TRACE_BRANCH_PROFILING | |
| help | |
| This tracer profiles all branch conditions. Every if () | |
| taken in the kernel is recorded whether it hit or miss. | |
| The results will be displayed in: | |
| /debugfs/tracing/profile_branch | |
| This configuration, when enabled, will impose a great overhead | |
| on the system. This should only be enabled when the system | |
| is to be analyzed | |
| Say N if unsure. | |
| config TRACING_BRANCHES | |
| bool | |
| help | |
| Selected by tracers that will trace the likely and unlikely | |
| conditions. This prevents the tracers themselves from being | |
| profiled. Profiling the tracing infrastructure can only happen | |
| when the likelys and unlikelys are not being traced. | |
| config BRANCH_TRACER | |
| bool "Trace likely/unlikely instances" | |
| depends on TRACE_BRANCH_PROFILING | |
| select TRACING_BRANCHES | |
| help | |
| This traces the events of likely and unlikely condition | |
| calls in the kernel. The difference between this and the | |
| "Trace likely/unlikely profiler" is that this is not a | |
| histogram of the callers, but actually places the calling | |
| events into a running trace buffer to see when and where the | |
| events happened, as well as their results. | |
| Say N if unsure. | |
| config POWER_TRACER | |
| bool "Trace power consumption behavior" | |
| depends on DEBUG_KERNEL | |
| depends on X86 | |
| select TRACING | |
| help | |
| This tracer helps developers to analyze and optimize the kernels | |
| power management decisions, specifically the C-state and P-state | |
| behavior. | |
| 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. If this is configured with DYNAMIC_FTRACE | |
| then it will not have any overhead while the stack tracer | |
| is disabled. | |
| To enable the stack tracer on bootup, pass in 'stacktrace' | |
| on the kernel command line. | |
| The stack tracer can also be enabled or disabled via the | |
| sysctl kernel.stack_tracer_enabled | |
| Say N if unsure. | |
| config HW_BRANCH_TRACER | |
| depends on HAVE_HW_BRANCH_TRACER | |
| bool "Trace hw branches" | |
| select TRACING | |
| help | |
| This tracer records all branches on the system in a circular | |
| buffer giving access to the last N branches for each cpu. | |
| 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 |