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         help
  15           See Documentation/trace/ftrace-design.txt
  16
  17 config HAVE_FUNCTION_TRACER
  18         bool
  19         help
  20           See Documentation/trace/ftrace-design.txt
  21
  22 config HAVE_FUNCTION_GRAPH_TRACER
  23         bool
  24         help
  25           See Documentation/trace/ftrace-design.txt
  26
  27 config HAVE_FUNCTION_GRAPH_FP_TEST
  28         bool
  29         help
  30           See Documentation/trace/ftrace-design.txt
  31
  32 config HAVE_FUNCTION_TRACE_MCOUNT_TEST
  33         bool
  34         help
  35           See Documentation/trace/ftrace-design.txt
  36
  37 config HAVE_DYNAMIC_FTRACE
  38         bool
  39         help
  40           See Documentation/trace/ftrace-design.txt
  41
  42 config HAVE_FTRACE_MCOUNT_RECORD
  43         bool
  44         help
  45           See Documentation/trace/ftrace-design.txt
  46
  47 config HAVE_SYSCALL_TRACEPOINTS
  48         bool
  49         help
  50           See Documentation/trace/ftrace-design.txt
  51
  52 config HAVE_C_RECORDMCOUNT
  53         bool
  54         help
  55           C version of recordmcount available?
  56
  57 config TRACER_MAX_TRACE
  58         bool
  59
  60 config RING_BUFFER
  61         bool
  62
  63 config FTRACE_NMI_ENTER
  64        bool
  65        depends on HAVE_FTRACE_NMI_ENTER
  66        default y
  67
  68 config EVENT_TRACING
  69         select CONTEXT_SWITCH_TRACER
  70         bool
  71
  72 config CONTEXT_SWITCH_TRACER
  73         bool
  74
  75 config RING_BUFFER_ALLOW_SWAP
  76         bool
  77         help
  78          Allow the use of ring_buffer_swap_cpu.
  79          Adds a very slight overhead to tracing when enabled.
  80
  81 # All tracer options should select GENERIC_TRACER. For those options that are
  82 # enabled by all tracers (context switch and event tracer) they select TRACING.
  83 # This allows those options to appear when no other tracer is selected. But the
  84 # options do not appear when something else selects it. We need the two options
  85 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
  86 # hiding of the automatic options.
  87
  88 config TRACING
  89         bool
  90         select DEBUG_FS
  91         select RING_BUFFER
  92         select STACKTRACE if STACKTRACE_SUPPORT
  93         select TRACEPOINTS
  94         select NOP_TRACER
  95         select BINARY_PRINTF
  96         select EVENT_TRACING
  97
  98 config GENERIC_TRACER
  99         bool
 100         select TRACING
 101
 102 #
 103 # Minimum requirements an architecture has to meet for us to
 104 # be able to offer generic tracing facilities:
 105 #
 106 config TRACING_SUPPORT
 107         bool
 108         # PPC32 has no irqflags tracing support, but it can use most of the
 109         # tracers anyway, they were tested to build and work. Note that new
 110         # exceptions to this list aren't welcomed, better implement the
 111         # irqflags tracing for your architecture.
 112         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
 113         depends on STACKTRACE_SUPPORT
 114         default y
 115
 116 if TRACING_SUPPORT
 117
 118 menuconfig FTRACE
 119         bool "Tracers"
 120         default y if DEBUG_KERNEL
 121         help
 122           Enable the kernel tracing infrastructure.
 123
 124 if FTRACE
 125
 126 config FUNCTION_TRACER
 127         bool "Kernel Function Tracer"
 128         depends on HAVE_FUNCTION_TRACER
 129         select FRAME_POINTER if (!ARM_UNWIND)
 130         select KALLSYMS
 131         select GENERIC_TRACER
 132         select CONTEXT_SWITCH_TRACER
 133         help
 134           Enable the kernel to trace every kernel function. This is done
 135           by using a compiler feature to insert a small, 5-byte No-Operation
 136           instruction at the beginning of every kernel function, which NOP
 137           sequence is then dynamically patched into a tracer call when
 138           tracing is enabled by the administrator. If it's runtime disabled
 139           (the bootup default), then the overhead of the instructions is very
 140           small and not measurable even in micro-benchmarks.
 141
 142 config FUNCTION_GRAPH_TRACER
 143         bool "Kernel Function Graph Tracer"
 144         depends on HAVE_FUNCTION_GRAPH_TRACER
 145         depends on FUNCTION_TRACER
 146         depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 147         default y
 148         help
 149           Enable the kernel to trace a function at both its return
 150           and its entry.
 151           Its first purpose is to trace the duration of functions and
 152           draw a call graph for each thread with some information like
 153           the return value. This is done by setting the current return
 154           address on the current task structure into a stack of calls.
 155
 156
 157 config IRQSOFF_TRACER
 158         bool "Interrupts-off Latency Tracer"
 159         default n
 160         depends on TRACE_IRQFLAGS_SUPPORT
 161         depends on !ARCH_USES_GETTIMEOFFSET
 162         select TRACE_IRQFLAGS
 163         select GENERIC_TRACER
 164         select TRACER_MAX_TRACE
 165         select RING_BUFFER_ALLOW_SWAP
 166         help
 167           This option measures the time spent in irqs-off critical
 168           sections, with microsecond accuracy.
 169
 170           The default measurement method is a maximum search, which is
 171           disabled by default and can be runtime (re-)started
 172           via:
 173
 174               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 175
 176           (Note that kernel size and overhead increase with this option
 177           enabled. This option and the preempt-off timing option can be
 178           used together or separately.)
 179
 180 config PREEMPT_TRACER
 181         bool "Preemption-off Latency Tracer"
 182         default n
 183         depends on !ARCH_USES_GETTIMEOFFSET
 184         depends on PREEMPT
 185         select GENERIC_TRACER
 186         select TRACER_MAX_TRACE
 187         select RING_BUFFER_ALLOW_SWAP
 188         help
 189           This option measures the time spent in preemption-off critical
 190           sections, with microsecond accuracy.
 191
 192           The default measurement method is a maximum search, which is
 193           disabled by default and can be runtime (re-)started
 194           via:
 195
 196               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 197
 198           (Note that kernel size and overhead increase with this option
 199           enabled. This option and the irqs-off timing option can be
 200           used together or separately.)
 201
 202 config SCHED_TRACER
 203         bool "Scheduling Latency Tracer"
 204         select GENERIC_TRACER
 205         select CONTEXT_SWITCH_TRACER
 206         select TRACER_MAX_TRACE
 207         help
 208           This tracer tracks the latency of the highest priority task
 209           to be scheduled in, starting from the point it has woken up.
 210
 211 config ENABLE_DEFAULT_TRACERS
 212         bool "Trace process context switches and events"
 213         depends on !GENERIC_TRACER
 214         select TRACING
 215         help
 216           This tracer hooks to various trace points in the kernel,
 217           allowing the user to pick and choose which trace point they
 218           want to trace. It also includes the sched_switch tracer plugin.
 219
 220 config FTRACE_SYSCALLS
 221         bool "Trace syscalls"
 222         depends on HAVE_SYSCALL_TRACEPOINTS
 223         select GENERIC_TRACER
 224         select KALLSYMS
 225         help
 226           Basic tracer to catch the syscall entry and exit events.
 227
 228 config TRACE_BRANCH_PROFILING
 229         bool
 230         select GENERIC_TRACER
 231
 232 choice
 233         prompt "Branch Profiling"
 234         default BRANCH_PROFILE_NONE
 235         help
 236          The branch profiling is a software profiler. It will add hooks
 237          into the C conditionals to test which path a branch takes.
 238
 239          The likely/unlikely profiler only looks at the conditions that
 240          are annotated with a likely or unlikely macro.
 241
 242          The "all branch" profiler will profile every if-statement in the
 243          kernel. This profiler will also enable the likely/unlikely
 244          profiler.
 245
 246          Either of the above profilers adds a bit of overhead to the system.
 247          If unsure, choose "No branch profiling".
 248
 249 config BRANCH_PROFILE_NONE
 250         bool "No branch profiling"
 251         help
 252           No branch profiling. Branch profiling adds a bit of overhead.
 253           Only enable it if you want to analyse the branching behavior.
 254           Otherwise keep it disabled.
 255
 256 config PROFILE_ANNOTATED_BRANCHES
 257         bool "Trace likely/unlikely profiler"
 258         select TRACE_BRANCH_PROFILING
 259         help
 260           This tracer profiles all the the likely and unlikely macros
 261           in the kernel. It will display the results in:
 262
 263           /sys/kernel/debug/tracing/profile_annotated_branch
 264
 265           Note: this will add a significant overhead; only turn this
 266           on if you need to profile the system's use of these macros.
 267
 268 config PROFILE_ALL_BRANCHES
 269         bool "Profile all if conditionals"
 270         select TRACE_BRANCH_PROFILING
 271         help
 272           This tracer profiles all branch conditions. Every if ()
 273           taken in the kernel is recorded whether it hit or miss.
 274           The results will be displayed in:
 275
 276           /sys/kernel/debug/tracing/profile_branch
 277
 278           This option also enables the likely/unlikely profiler.
 279
 280           This configuration, when enabled, will impose a great overhead
 281           on the system. This should only be enabled when the system
 282           is to be analyzed in much detail.
 283 endchoice
 284
 285 config TRACING_BRANCHES
 286         bool
 287         help
 288           Selected by tracers that will trace the likely and unlikely
 289           conditions. This prevents the tracers themselves from being
 290           profiled. Profiling the tracing infrastructure can only happen
 291           when the likelys and unlikelys are not being traced.
 292
 293 config BRANCH_TRACER
 294         bool "Trace likely/unlikely instances"
 295         depends on TRACE_BRANCH_PROFILING
 296         select TRACING_BRANCHES
 297         help
 298           This traces the events of likely and unlikely condition
 299           calls in the kernel.  The difference between this and the
 300           "Trace likely/unlikely profiler" is that this is not a
 301           histogram of the callers, but actually places the calling
 302           events into a running trace buffer to see when and where the
 303           events happened, as well as their results.
 304
 305           Say N if unsure.
 306
 307 config STACK_TRACER
 308         bool "Trace max stack"
 309         depends on HAVE_FUNCTION_TRACER
 310         select FUNCTION_TRACER
 311         select STACKTRACE
 312         select KALLSYMS
 313         help
 314           This special tracer records the maximum stack footprint of the
 315           kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 316
 317           This tracer works by hooking into every function call that the
 318           kernel executes, and keeping a maximum stack depth value and
 319           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 320           then it will not have any overhead while the stack tracer
 321           is disabled.
 322
 323           To enable the stack tracer on bootup, pass in 'stacktrace'
 324           on the kernel command line.
 325
 326           The stack tracer can also be enabled or disabled via the
 327           sysctl kernel.stack_tracer_enabled
 328
 329           Say N if unsure.
 330
 331 config BLK_DEV_IO_TRACE
 332         bool "Support for tracing block IO actions"
 333         depends on SYSFS
 334         depends on BLOCK
 335         select RELAY
 336         select DEBUG_FS
 337         select TRACEPOINTS
 338         select GENERIC_TRACER
 339         select STACKTRACE
 340         help
 341           Say Y here if you want to be able to trace the block layer actions
 342           on a given queue. Tracing allows you to see any traffic happening
 343           on a block device queue. For more information (and the userspace
 344           support tools needed), fetch the blktrace tools from:
 345
 346           git://git.kernel.dk/blktrace.git
 347
 348           Tracing also is possible using the ftrace interface, e.g.:
 349
 350             echo 1 > /sys/block/sda/sda1/trace/enable
 351             echo blk > /sys/kernel/debug/tracing/current_tracer
 352             cat /sys/kernel/debug/tracing/trace_pipe
 353
 354           If unsure, say N.
 355
 356 config KPROBE_EVENT
 357         depends on KPROBES
 358         depends on HAVE_REGS_AND_STACK_ACCESS_API
 359         bool "Enable kprobes-based dynamic events"
 360         select TRACING
 361         default y
 362         help
 363           This allows the user to add tracing events (similar to tracepoints)
 364           on the fly via the ftrace interface. See
 365           Documentation/trace/kprobetrace.txt for more details.
 366
 367           Those events can be inserted wherever kprobes can probe, and record
 368           various register and memory values.
 369
 370           This option is also required by perf-probe subcommand of perf tools.
 371           If you want to use perf tools, this option is strongly recommended.
 372
 373 config DYNAMIC_FTRACE
 374         bool "enable/disable ftrace tracepoints dynamically"
 375         depends on FUNCTION_TRACER
 376         depends on HAVE_DYNAMIC_FTRACE
 377         default y
 378         help
 379           This option will modify all the calls to ftrace dynamically
 380           (will patch them out of the binary image and replace them
 381           with a No-Op instruction) as they are called. A table is
 382           created to dynamically enable them again.
 383
 384           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 385           otherwise has native performance as long as no tracing is active.
 386
 387           The changes to the code are done by a kernel thread that
 388           wakes up once a second and checks to see if any ftrace calls
 389           were made. If so, it runs stop_machine (stops all CPUS)
 390           and modifies the code to jump over the call to ftrace.
 391
 392 config FUNCTION_PROFILER
 393         bool "Kernel function profiler"
 394         depends on FUNCTION_TRACER
 395         default n
 396         help
 397           This option enables the kernel function profiler. A file is created
 398           in debugfs called function_profile_enabled which defaults to zero.
 399           When a 1 is echoed into this file profiling begins, and when a
 400           zero is entered, profiling stops. A "functions" file is created in
 401           the trace_stats directory; this file shows the list of functions that
 402           have been hit and their counters.
 403
 404           If in doubt, say N.
 405
 406 config FTRACE_MCOUNT_RECORD
 407         def_bool y
 408         depends on DYNAMIC_FTRACE
 409         depends on HAVE_FTRACE_MCOUNT_RECORD
 410
 411 config FTRACE_SELFTEST
 412         bool
 413
 414 config FTRACE_STARTUP_TEST
 415         bool "Perform a startup test on ftrace"
 416         depends on GENERIC_TRACER
 417         select FTRACE_SELFTEST
 418         help
 419           This option performs a series of startup tests on ftrace. On bootup
 420           a series of tests are made to verify that the tracer is
 421           functioning properly. It will do tests on all the configured
 422           tracers of ftrace.
 423
 424 config EVENT_TRACE_TEST_SYSCALLS
 425         bool "Run selftest on syscall events"
 426         depends on FTRACE_STARTUP_TEST
 427         help
 428          This option will also enable testing every syscall event.
 429          It only enables the event and disables it and runs various loads
 430          with the event enabled. This adds a bit more time for kernel boot
 431          up since it runs this on every system call defined.
 432
 433          TBD - enable a way to actually call the syscalls as we test their
 434                events
 435
 436 config MMIOTRACE
 437         bool "Memory mapped IO tracing"
 438         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 439         select GENERIC_TRACER
 440         help
 441           Mmiotrace traces Memory Mapped I/O access and is meant for
 442           debugging and reverse engineering. It is called from the ioremap
 443           implementation and works via page faults. Tracing is disabled by
 444           default and can be enabled at run-time.
 445
 446           See Documentation/trace/mmiotrace.txt.
 447           If you are not helping to develop drivers, say N.
 448
 449 config MMIOTRACE_TEST
 450         tristate "Test module for mmiotrace"
 451         depends on MMIOTRACE && m
 452         help
 453           This is a dumb module for testing mmiotrace. It is very dangerous
 454           as it will write garbage to IO memory starting at a given address.
 455           However, it should be safe to use on e.g. unused portion of VRAM.
 456
 457           Say N, unless you absolutely know what you are doing.
 458
 459 config RING_BUFFER_BENCHMARK
 460         tristate "Ring buffer benchmark stress tester"
 461         depends on RING_BUFFER
 462         help
 463           This option creates a test to stress the ring buffer and benchmark it.
 464           It creates its own ring buffer such that it will not interfere with
 465           any other users of the ring buffer (such as ftrace). It then creates
 466           a producer and consumer that will run for 10 seconds and sleep for
 467           10 seconds. Each interval it will print out the number of events
 468           it recorded and give a rough estimate of how long each iteration took.
 469
 470           It does not disable interrupts or raise its priority, so it may be
 471           affected by processes that are running.
 472
 473           If unsure, say N.
 474
 475 endif # FTRACE
 476
 477 endif # TRACING_SUPPORT
 478