kernel/trace/Kconfig

   1 #
   2 # Architectures that offer an FUNCTION_TRACER implementation should
   3 #  select HAVE_FUNCTION_TRACER:
   4 #
   5
   6 config USER_STACKTRACE_SUPPORT
   7         bool
   8
   9 config NOP_TRACER
  10         bool
  11
  12 config HAVE_FTRACE_NMI_ENTER
  13         bool
  14
  15 config HAVE_FUNCTION_TRACER
  16         bool
  17
  18 config HAVE_FUNCTION_GRAPH_TRACER
  19         bool
  20
  21 config HAVE_FUNCTION_TRACE_MCOUNT_TEST
  22         bool
  23         help
  24          This gets selected when the arch tests the function_trace_stop
  25          variable at the mcount call site. Otherwise, this variable
  26          is tested by the called function.
  27
  28 config HAVE_DYNAMIC_FTRACE
  29         bool
  30
  31 config HAVE_FTRACE_MCOUNT_RECORD
  32         bool
  33
  34 config HAVE_HW_BRANCH_TRACER
  35         bool
  36
  37 config HAVE_FTRACE_SYSCALLS
  38         bool
  39
  40 config TRACER_MAX_TRACE
  41         bool
  42
  43 config RING_BUFFER
  44         bool
  45
  46 config FTRACE_NMI_ENTER
  47        bool
  48        depends on HAVE_FTRACE_NMI_ENTER
  49        default y
  50
  51 config EVENT_TRACING
  52         bool
  53
  54 config TRACING
  55         bool
  56         select DEBUG_FS
  57         select RING_BUFFER
  58         select STACKTRACE if STACKTRACE_SUPPORT
  59         select TRACEPOINTS
  60         select NOP_TRACER
  61         select BINARY_PRINTF
  62         select EVENT_TRACING
  63
  64 #
  65 # Minimum requirements an architecture has to meet for us to
  66 # be able to offer generic tracing facilities:
  67 #
  68 config TRACING_SUPPORT
  69         bool
  70         # PPC32 has no irqflags tracing support, but it can use most of the
  71         # tracers anyway, they were tested to build and work. Note that new
  72         # exceptions to this list aren't welcomed, better implement the
  73         # irqflags tracing for your architecture.
  74         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
  75         depends on STACKTRACE_SUPPORT
  76         default y
  77
  78 if TRACING_SUPPORT
  79
  80 menu "Tracers"
  81
  82 config FUNCTION_TRACER
  83         bool "Kernel Function Tracer"
  84         depends on HAVE_FUNCTION_TRACER
  85         select FRAME_POINTER
  86         select KALLSYMS
  87         select TRACING
  88         select CONTEXT_SWITCH_TRACER
  89         help
  90           Enable the kernel to trace every kernel function. This is done
  91           by using a compiler feature to insert a small, 5-byte No-Operation
  92           instruction to the beginning of every kernel function, which NOP
  93           sequence is then dynamically patched into a tracer call when
  94           tracing is enabled by the administrator. If it's runtime disabled
  95           (the bootup default), then the overhead of the instructions is very
  96           small and not measurable even in micro-benchmarks.
  97
  98 config FUNCTION_GRAPH_TRACER
  99         bool "Kernel Function Graph Tracer"
 100         depends on HAVE_FUNCTION_GRAPH_TRACER
 101         depends on FUNCTION_TRACER
 102         default y
 103         help
 104           Enable the kernel to trace a function at both its return
 105           and its entry.
 106           Its first purpose is to trace the duration of functions and
 107           draw a call graph for each thread with some information like
 108           the return value. This is done by setting the current return
 109           address on the current task structure into a stack of calls.
 110
 111
 112 config IRQSOFF_TRACER
 113         bool "Interrupts-off Latency Tracer"
 114         default n
 115         depends on TRACE_IRQFLAGS_SUPPORT
 116         depends on GENERIC_TIME
 117         select TRACE_IRQFLAGS
 118         select TRACING
 119         select TRACER_MAX_TRACE
 120         help
 121           This option measures the time spent in irqs-off critical
 122           sections, with microsecond accuracy.
 123
 124           The default measurement method is a maximum search, which is
 125           disabled by default and can be runtime (re-)started
 126           via:
 127
 128               echo 0 > /debugfs/tracing/tracing_max_latency
 129
 130           (Note that kernel size and overhead increases with this option
 131           enabled. This option and the preempt-off timing option can be
 132           used together or separately.)
 133
 134 config PREEMPT_TRACER
 135         bool "Preemption-off Latency Tracer"
 136         default n
 137         depends on GENERIC_TIME
 138         depends on PREEMPT
 139         select TRACING
 140         select TRACER_MAX_TRACE
 141         help
 142           This option measures the time spent in preemption off critical
 143           sections, with microsecond accuracy.
 144
 145           The default measurement method is a maximum search, which is
 146           disabled by default and can be runtime (re-)started
 147           via:
 148
 149               echo 0 > /debugfs/tracing/tracing_max_latency
 150
 151           (Note that kernel size and overhead increases with this option
 152           enabled. This option and the irqs-off timing option can be
 153           used together or separately.)
 154
 155 config SYSPROF_TRACER
 156         bool "Sysprof Tracer"
 157         depends on X86
 158         select TRACING
 159         select CONTEXT_SWITCH_TRACER
 160         help
 161           This tracer provides the trace needed by the 'Sysprof' userspace
 162           tool.
 163
 164 config SCHED_TRACER
 165         bool "Scheduling Latency Tracer"
 166         select TRACING
 167         select CONTEXT_SWITCH_TRACER
 168         select TRACER_MAX_TRACE
 169         help
 170           This tracer tracks the latency of the highest priority task
 171           to be scheduled in, starting from the point it has woken up.
 172
 173 config CONTEXT_SWITCH_TRACER
 174         bool "Trace process context switches"
 175         select TRACING
 176         select MARKERS
 177         help
 178           This tracer gets called from the context switch and records
 179           all switching of tasks.
 180
 181 config EVENT_TRACER
 182         bool "Trace various events in the kernel"
 183         select TRACING
 184         help
 185           This tracer hooks to various trace points in the kernel
 186           allowing the user to pick and choose which trace point they
 187           want to trace.
 188
 189 config FTRACE_SYSCALLS
 190         bool "Trace syscalls"
 191         depends on HAVE_FTRACE_SYSCALLS
 192         select TRACING
 193         select KALLSYMS
 194         help
 195           Basic tracer to catch the syscall entry and exit events.
 196
 197 config BOOT_TRACER
 198         bool "Trace boot initcalls"
 199         select TRACING
 200         select CONTEXT_SWITCH_TRACER
 201         help
 202           This tracer helps developers to optimize boot times: it records
 203           the timings of the initcalls and traces key events and the identity
 204           of tasks that can cause boot delays, such as context-switches.
 205
 206           Its aim is to be parsed by the /scripts/bootgraph.pl tool to
 207           produce pretty graphics about boot inefficiencies, giving a visual
 208           representation of the delays during initcalls - but the raw
 209           /debug/tracing/trace text output is readable too.
 210
 211           You must pass in ftrace=initcall to the kernel command line
 212           to enable this on bootup.
 213
 214 config TRACE_BRANCH_PROFILING
 215         bool "Trace likely/unlikely profiler"
 216         select TRACING
 217         help
 218           This tracer profiles all the the likely and unlikely macros
 219           in the kernel. It will display the results in:
 220
 221           /debugfs/tracing/profile_annotated_branch
 222
 223           Note: this will add a significant overhead, only turn this
 224           on if you need to profile the system's use of these macros.
 225
 226           Say N if unsure.
 227
 228 config PROFILE_ALL_BRANCHES
 229         bool "Profile all if conditionals"
 230         depends on TRACE_BRANCH_PROFILING
 231         help
 232           This tracer profiles all branch conditions. Every if ()
 233           taken in the kernel is recorded whether it hit or miss.
 234           The results will be displayed in:
 235
 236           /debugfs/tracing/profile_branch
 237
 238           This configuration, when enabled, will impose a great overhead
 239           on the system. This should only be enabled when the system
 240           is to be analyzed
 241
 242           Say N if unsure.
 243
 244 config TRACING_BRANCHES
 245         bool
 246         help
 247           Selected by tracers that will trace the likely and unlikely
 248           conditions. This prevents the tracers themselves from being
 249           profiled. Profiling the tracing infrastructure can only happen
 250           when the likelys and unlikelys are not being traced.
 251
 252 config BRANCH_TRACER
 253         bool "Trace likely/unlikely instances"
 254         depends on TRACE_BRANCH_PROFILING
 255         select TRACING_BRANCHES
 256         help
 257           This traces the events of likely and unlikely condition
 258           calls in the kernel.  The difference between this and the
 259           "Trace likely/unlikely profiler" is that this is not a
 260           histogram of the callers, but actually places the calling
 261           events into a running trace buffer to see when and where the
 262           events happened, as well as their results.
 263
 264           Say N if unsure.
 265
 266 config POWER_TRACER
 267         bool "Trace power consumption behavior"
 268         depends on X86
 269         select TRACING
 270         help
 271           This tracer helps developers to analyze and optimize the kernels
 272           power management decisions, specifically the C-state and P-state
 273           behavior.
 274
 275
 276 config STACK_TRACER
 277         bool "Trace max stack"
 278         depends on HAVE_FUNCTION_TRACER
 279         select FUNCTION_TRACER
 280         select STACKTRACE
 281         select KALLSYMS
 282         help
 283           This special tracer records the maximum stack footprint of the
 284           kernel and displays it in debugfs/tracing/stack_trace.
 285
 286           This tracer works by hooking into every function call that the
 287           kernel executes, and keeping a maximum stack depth value and
 288           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 289           then it will not have any overhead while the stack tracer
 290           is disabled.
 291
 292           To enable the stack tracer on bootup, pass in 'stacktrace'
 293           on the kernel command line.
 294
 295           The stack tracer can also be enabled or disabled via the
 296           sysctl kernel.stack_tracer_enabled
 297
 298           Say N if unsure.
 299
 300 config HW_BRANCH_TRACER
 301         depends on HAVE_HW_BRANCH_TRACER
 302         bool "Trace hw branches"
 303         select TRACING
 304         help
 305           This tracer records all branches on the system in a circular
 306           buffer giving access to the last N branches for each cpu.
 307
 308 config KMEMTRACE
 309         bool "Trace SLAB allocations"
 310         select TRACING
 311         help
 312           kmemtrace provides tracing for slab allocator functions, such as
 313           kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
 314           data is then fed to the userspace application in order to analyse
 315           allocation hotspots, internal fragmentation and so on, making it
 316           possible to see how well an allocator performs, as well as debug
 317           and profile kernel code.
 318
 319           This requires an userspace application to use. See
 320           Documentation/trace/kmemtrace.txt for more information.
 321
 322           Saying Y will make the kernel somewhat larger and slower. However,
 323           if you disable kmemtrace at run-time or boot-time, the performance
 324           impact is minimal (depending on the arch the kernel is built for).
 325
 326           If unsure, say N.
 327
 328 config WORKQUEUE_TRACER
 329         bool "Trace workqueues"
 330         select TRACING
 331         help
 332           The workqueue tracer provides some statistical informations
 333           about each cpu workqueue thread such as the number of the
 334           works inserted and executed since their creation. It can help
 335           to evaluate the amount of work each of them have to perform.
 336           For example it can help a developer to decide whether he should
 337           choose a per cpu workqueue instead of a singlethreaded one.
 338
 339 config BLK_DEV_IO_TRACE
 340         bool "Support for tracing block io actions"
 341         depends on SYSFS
 342         depends on BLOCK
 343         select RELAY
 344         select DEBUG_FS
 345         select TRACEPOINTS
 346         select TRACING
 347         select STACKTRACE
 348         help
 349           Say Y here if you want to be able to trace the block layer actions
 350           on a given queue. Tracing allows you to see any traffic happening
 351           on a block device queue. For more information (and the userspace
 352           support tools needed), fetch the blktrace tools from:
 353
 354           git://git.kernel.dk/blktrace.git
 355
 356           Tracing also is possible using the ftrace interface, e.g.:
 357
 358             echo 1 > /sys/block/sda/sda1/trace/enable
 359             echo blk > /sys/kernel/debug/tracing/current_tracer
 360             cat /sys/kernel/debug/tracing/trace_pipe
 361
 362           If unsure, say N.
 363
 364 config DYNAMIC_FTRACE
 365         bool "enable/disable ftrace tracepoints dynamically"
 366         depends on FUNCTION_TRACER
 367         depends on HAVE_DYNAMIC_FTRACE
 368         default y
 369         help
 370          This option will modify all the calls to ftrace dynamically
 371          (will patch them out of the binary image and replaces them
 372          with a No-Op instruction) as they are called. A table is
 373          created to dynamically enable them again.
 374
 375          This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
 376          has native performance as long as no tracing is active.
 377
 378          The changes to the code are done by a kernel thread that
 379          wakes up once a second and checks to see if any ftrace calls
 380          were made. If so, it runs stop_machine (stops all CPUS)
 381          and modifies the code to jump over the call to ftrace.
 382
 383 config FUNCTION_PROFILER
 384         bool "Kernel function profiler"
 385         depends on FUNCTION_TRACER
 386         default n
 387         help
 388          This option enables the kernel function profiler. A file is created
 389          in debugfs called function_profile_enabled which defaults to zero.
 390          When a 1 is echoed into this file profiling begins, and when a
 391          zero is entered, profiling stops. A file in the trace_stats
 392          directory called functions, that show the list of functions that
 393          have been hit and their counters.
 394
 395          If in doubt, say N
 396
 397 config FTRACE_MCOUNT_RECORD
 398         def_bool y
 399         depends on DYNAMIC_FTRACE
 400         depends on HAVE_FTRACE_MCOUNT_RECORD
 401
 402 config FTRACE_SELFTEST
 403         bool
 404
 405 config FTRACE_STARTUP_TEST
 406         bool "Perform a startup test on ftrace"
 407         depends on TRACING
 408         select FTRACE_SELFTEST
 409         help
 410           This option performs a series of startup tests on ftrace. On bootup
 411           a series of tests are made to verify that the tracer is
 412           functioning properly. It will do tests on all the configured
 413           tracers of ftrace.
 414
 415 config MMIOTRACE
 416         bool "Memory mapped IO tracing"
 417         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 418         select TRACING
 419         help
 420           Mmiotrace traces Memory Mapped I/O access and is meant for
 421           debugging and reverse engineering. It is called from the ioremap
 422           implementation and works via page faults. Tracing is disabled by
 423           default and can be enabled at run-time.
 424
 425           See Documentation/trace/mmiotrace.txt.
 426           If you are not helping to develop drivers, say N.
 427
 428 config MMIOTRACE_TEST
 429         tristate "Test module for mmiotrace"
 430         depends on MMIOTRACE && m
 431         help
 432           This is a dumb module for testing mmiotrace. It is very dangerous
 433           as it will write garbage to IO memory starting at a given address.
 434           However, it should be safe to use on e.g. unused portion of VRAM.
 435
 436           Say N, unless you absolutely know what you are doing.
 437
 438 endmenu
 439
 440 endif # TRACING_SUPPORT
 441