Kconfig 5.5 KB

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  1. #
  2. # Architectures that offer an FTRACE implementation should select HAVE_FTRACE:
  3. #
  4. config NOP_TRACER
  5. bool
  6. config HAVE_FTRACE
  7. bool
  8. select NOP_TRACER
  9. config HAVE_DYNAMIC_FTRACE
  10. bool
  11. config HAVE_FTRACE_MCOUNT_RECORD
  12. bool
  13. config TRACER_MAX_TRACE
  14. bool
  15. config RING_BUFFER
  16. bool
  17. config TRACING
  18. bool
  19. select DEBUG_FS
  20. select RING_BUFFER
  21. select STACKTRACE
  22. select TRACEPOINTS
  23. config FTRACE
  24. bool "Kernel Function Tracer"
  25. depends on HAVE_FTRACE
  26. depends on DEBUG_KERNEL
  27. select FRAME_POINTER
  28. select TRACING
  29. select CONTEXT_SWITCH_TRACER
  30. help
  31. Enable the kernel to trace every kernel function. This is done
  32. by using a compiler feature to insert a small, 5-byte No-Operation
  33. instruction to the beginning of every kernel function, which NOP
  34. sequence is then dynamically patched into a tracer call when
  35. tracing is enabled by the administrator. If it's runtime disabled
  36. (the bootup default), then the overhead of the instructions is very
  37. small and not measurable even in micro-benchmarks.
  38. config IRQSOFF_TRACER
  39. bool "Interrupts-off Latency Tracer"
  40. default n
  41. depends on TRACE_IRQFLAGS_SUPPORT
  42. depends on GENERIC_TIME
  43. depends on DEBUG_KERNEL
  44. select TRACE_IRQFLAGS
  45. select TRACING
  46. select TRACER_MAX_TRACE
  47. help
  48. This option measures the time spent in irqs-off critical
  49. sections, with microsecond accuracy.
  50. The default measurement method is a maximum search, which is
  51. disabled by default and can be runtime (re-)started
  52. via:
  53. echo 0 > /debugfs/tracing/tracing_max_latency
  54. (Note that kernel size and overhead increases with this option
  55. enabled. This option and the preempt-off timing option can be
  56. used together or separately.)
  57. config PREEMPT_TRACER
  58. bool "Preemption-off Latency Tracer"
  59. default n
  60. depends on GENERIC_TIME
  61. depends on PREEMPT
  62. depends on DEBUG_KERNEL
  63. select TRACING
  64. select TRACER_MAX_TRACE
  65. help
  66. This option measures the time spent in preemption off critical
  67. sections, with microsecond accuracy.
  68. The default measurement method is a maximum search, which is
  69. disabled by default and can be runtime (re-)started
  70. via:
  71. echo 0 > /debugfs/tracing/tracing_max_latency
  72. (Note that kernel size and overhead increases with this option
  73. enabled. This option and the irqs-off timing option can be
  74. used together or separately.)
  75. config SYSPROF_TRACER
  76. bool "Sysprof Tracer"
  77. depends on X86
  78. select TRACING
  79. help
  80. This tracer provides the trace needed by the 'Sysprof' userspace
  81. tool.
  82. config SCHED_TRACER
  83. bool "Scheduling Latency Tracer"
  84. depends on DEBUG_KERNEL
  85. select TRACING
  86. select CONTEXT_SWITCH_TRACER
  87. select TRACER_MAX_TRACE
  88. help
  89. This tracer tracks the latency of the highest priority task
  90. to be scheduled in, starting from the point it has woken up.
  91. config CONTEXT_SWITCH_TRACER
  92. bool "Trace process context switches"
  93. depends on DEBUG_KERNEL
  94. select TRACING
  95. select MARKERS
  96. help
  97. This tracer gets called from the context switch and records
  98. all switching of tasks.
  99. config BOOT_TRACER
  100. bool "Trace boot initcalls"
  101. depends on DEBUG_KERNEL
  102. select TRACING
  103. help
  104. This tracer helps developers to optimize boot times: it records
  105. the timings of the initcalls and traces key events and the identity
  106. of tasks that can cause boot delays, such as context-switches.
  107. Its aim is to be parsed by the /scripts/bootgraph.pl tool to
  108. produce pretty graphics about boot inefficiencies, giving a visual
  109. representation of the delays during initcalls - but the raw
  110. /debug/tracing/trace text output is readable too.
  111. ( Note that tracing self tests can't be enabled if this tracer is
  112. selected, because the self-tests are an initcall as well and that
  113. would invalidate the boot trace. )
  114. config STACK_TRACER
  115. bool "Trace max stack"
  116. depends on HAVE_FTRACE
  117. depends on DEBUG_KERNEL
  118. select FTRACE
  119. select STACKTRACE
  120. help
  121. This special tracer records the maximum stack footprint of the
  122. kernel and displays it in debugfs/tracing/stack_trace.
  123. This tracer works by hooking into every function call that the
  124. kernel executes, and keeping a maximum stack depth value and
  125. stack-trace saved. Because this logic has to execute in every
  126. kernel function, all the time, this option can slow down the
  127. kernel measurably and is generally intended for kernel
  128. developers only.
  129. Say N if unsure.
  130. config DYNAMIC_FTRACE
  131. bool "enable/disable ftrace tracepoints dynamically"
  132. depends on FTRACE
  133. depends on HAVE_DYNAMIC_FTRACE
  134. depends on DEBUG_KERNEL
  135. default y
  136. help
  137. This option will modify all the calls to ftrace dynamically
  138. (will patch them out of the binary image and replaces them
  139. with a No-Op instruction) as they are called. A table is
  140. created to dynamically enable them again.
  141. This way a CONFIG_FTRACE kernel is slightly larger, but otherwise
  142. has native performance as long as no tracing is active.
  143. The changes to the code are done by a kernel thread that
  144. wakes up once a second and checks to see if any ftrace calls
  145. were made. If so, it runs stop_machine (stops all CPUS)
  146. and modifies the code to jump over the call to ftrace.
  147. config FTRACE_MCOUNT_RECORD
  148. def_bool y
  149. depends on DYNAMIC_FTRACE
  150. depends on HAVE_FTRACE_MCOUNT_RECORD
  151. config FTRACE_SELFTEST
  152. bool
  153. config FTRACE_STARTUP_TEST
  154. bool "Perform a startup test on ftrace"
  155. depends on TRACING && DEBUG_KERNEL && !BOOT_TRACER
  156. select FTRACE_SELFTEST
  157. help
  158. This option performs a series of startup tests on ftrace. On bootup
  159. a series of tests are made to verify that the tracer is
  160. functioning properly. It will do tests on all the configured
  161. tracers of ftrace.