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_DYNAMIC_FTRACE_WITH_REGS
  43         bool
  44
  45 config HAVE_FTRACE_MCOUNT_RECORD
  46         bool
  47         help
  48           See Documentation/trace/ftrace-design.txt
  49
  50 config HAVE_SYSCALL_TRACEPOINTS
  51         bool
  52         help
  53           See Documentation/trace/ftrace-design.txt
  54
  55 config HAVE_FENTRY
  56         bool
  57         help
  58           Arch supports the gcc options -pg with -mfentry
  59
  60 config HAVE_C_RECORDMCOUNT
  61         bool
  62         help
  63           C version of recordmcount available?
  64
  65 config TRACER_MAX_TRACE
  66         bool
  67
  68 config TRACE_CLOCK
  69         bool
  70
  71 config RING_BUFFER
  72         bool
  73         select TRACE_CLOCK
  74
  75 config FTRACE_NMI_ENTER
  76        bool
  77        depends on HAVE_FTRACE_NMI_ENTER
  78        default y
  79
  80 config EVENT_TRACING
  81         select CONTEXT_SWITCH_TRACER
  82         bool
  83
  84 config EVENT_POWER_TRACING_DEPRECATED
  85         depends on EVENT_TRACING
  86         bool "Deprecated power event trace API, to be removed"
  87         default y
  88         help
  89           Provides old power event types:
  90           C-state/idle accounting events:
  91           power:power_start
  92           power:power_end
  93           and old cpufreq accounting event:
  94           power:power_frequency
  95           This is for userspace compatibility
  96           and will vanish after 5 kernel iterations,
  97           namely 3.1.
  98
  99 config CONTEXT_SWITCH_TRACER
 100         bool
 101
 102 config RING_BUFFER_ALLOW_SWAP
 103         bool
 104         help
 105          Allow the use of ring_buffer_swap_cpu.
 106          Adds a very slight overhead to tracing when enabled.
 107
 108 # All tracer options should select GENERIC_TRACER. For those options that are
 109 # enabled by all tracers (context switch and event tracer) they select TRACING.
 110 # This allows those options to appear when no other tracer is selected. But the
 111 # options do not appear when something else selects it. We need the two options
 112 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
 113 # hiding of the automatic options.
 114
 115 config TRACING
 116         bool
 117         select DEBUG_FS
 118         select RING_BUFFER
 119         select STACKTRACE if STACKTRACE_SUPPORT
 120         select TRACEPOINTS
 121         select NOP_TRACER
 122         select BINARY_PRINTF
 123         select EVENT_TRACING
 124         select TRACE_CLOCK
 125         select IRQ_WORK
 126
 127 config GENERIC_TRACER
 128         bool
 129         select TRACING
 130
 131 #
 132 # Minimum requirements an architecture has to meet for us to
 133 # be able to offer generic tracing facilities:
 134 #
 135 config TRACING_SUPPORT
 136         bool
 137         # PPC32 has no irqflags tracing support, but it can use most of the
 138         # tracers anyway, they were tested to build and work. Note that new
 139         # exceptions to this list aren't welcomed, better implement the
 140         # irqflags tracing for your architecture.
 141         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
 142         depends on STACKTRACE_SUPPORT
 143         default y
 144
 145 if TRACING_SUPPORT
 146
 147 menuconfig FTRACE
 148         bool "Tracers"
 149         default y if DEBUG_KERNEL
 150         help
 151           Enable the kernel tracing infrastructure.
 152
 153 if FTRACE
 154
 155 config FUNCTION_TRACER
 156         bool "Kernel Function Tracer"
 157         depends on HAVE_FUNCTION_TRACER
 158         select KALLSYMS
 159         select GENERIC_TRACER
 160         select CONTEXT_SWITCH_TRACER
 161         help
 162           Enable the kernel to trace every kernel function. This is done
 163           by using a compiler feature to insert a small, 5-byte No-Operation
 164           instruction at the beginning of every kernel function, which NOP
 165           sequence is then dynamically patched into a tracer call when
 166           tracing is enabled by the administrator. If it's runtime disabled
 167           (the bootup default), then the overhead of the instructions is very
 168           small and not measurable even in micro-benchmarks.
 169
 170 config FUNCTION_GRAPH_TRACER
 171         bool "Kernel Function Graph Tracer"
 172         depends on HAVE_FUNCTION_GRAPH_TRACER
 173         depends on FUNCTION_TRACER
 174         depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 175         default y
 176         help
 177           Enable the kernel to trace a function at both its return
 178           and its entry.
 179           Its first purpose is to trace the duration of functions and
 180           draw a call graph for each thread with some information like
 181           the return value. This is done by setting the current return
 182           address on the current task structure into a stack of calls.
 183
 184
 185 config IRQSOFF_TRACER
 186         bool "Interrupts-off Latency Tracer"
 187         default n
 188         depends on TRACE_IRQFLAGS_SUPPORT
 189         depends on !ARCH_USES_GETTIMEOFFSET
 190         select TRACE_IRQFLAGS
 191         select GENERIC_TRACER
 192         select TRACER_MAX_TRACE
 193         select RING_BUFFER_ALLOW_SWAP
 194         select TRACER_SNAPSHOT
 195         select TRACER_SNAPSHOT_PER_CPU_SWAP
 196         help
 197           This option measures the time spent in irqs-off critical
 198           sections, with microsecond accuracy.
 199
 200           The default measurement method is a maximum search, which is
 201           disabled by default and can be runtime (re-)started
 202           via:
 203
 204               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 205
 206           (Note that kernel size and overhead increase with this option
 207           enabled. This option and the preempt-off timing option can be
 208           used together or separately.)
 209
 210 config PREEMPT_TRACER
 211         bool "Preemption-off Latency Tracer"
 212         default n
 213         depends on !ARCH_USES_GETTIMEOFFSET
 214         depends on PREEMPT
 215         select GENERIC_TRACER
 216         select TRACER_MAX_TRACE
 217         select RING_BUFFER_ALLOW_SWAP
 218         select TRACER_SNAPSHOT
 219         select TRACER_SNAPSHOT_PER_CPU_SWAP
 220         help
 221           This option measures the time spent in preemption-off critical
 222           sections, with microsecond accuracy.
 223
 224           The default measurement method is a maximum search, which is
 225           disabled by default and can be runtime (re-)started
 226           via:
 227
 228               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 229
 230           (Note that kernel size and overhead increase with this option
 231           enabled. This option and the irqs-off timing option can be
 232           used together or separately.)
 233
 234 config SCHED_TRACER
 235         bool "Scheduling Latency Tracer"
 236         select GENERIC_TRACER
 237         select CONTEXT_SWITCH_TRACER
 238         select TRACER_MAX_TRACE
 239         select TRACER_SNAPSHOT
 240         help
 241           This tracer tracks the latency of the highest priority task
 242           to be scheduled in, starting from the point it has woken up.
 243
 244 config ENABLE_DEFAULT_TRACERS
 245         bool "Trace process context switches and events"
 246         depends on !GENERIC_TRACER
 247         select TRACING
 248         help
 249           This tracer hooks to various trace points in the kernel,
 250           allowing the user to pick and choose which trace point they
 251           want to trace. It also includes the sched_switch tracer plugin.
 252
 253 config FTRACE_SYSCALLS
 254         bool "Trace syscalls"
 255         depends on HAVE_SYSCALL_TRACEPOINTS
 256         select GENERIC_TRACER
 257         select KALLSYMS
 258         help
 259           Basic tracer to catch the syscall entry and exit events.
 260
 261 config TRACER_SNAPSHOT
 262         bool "Create a snapshot trace buffer"
 263         select TRACER_MAX_TRACE
 264         help
 265           Allow tracing users to take snapshot of the current buffer using the
 266           ftrace interface, e.g.:
 267
 268               echo 1 > /sys/kernel/debug/tracing/snapshot
 269               cat snapshot
 270
 271 config TRACER_SNAPSHOT_PER_CPU_SWAP
 272         bool "Allow snapshot to swap per CPU"
 273         depends on TRACER_SNAPSHOT
 274         select RING_BUFFER_ALLOW_SWAP
 275         help
 276           Allow doing a snapshot of a single CPU buffer instead of a
 277           full swap (all buffers). If this is set, then the following is
 278           allowed:
 279
 280               echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
 281
 282           After which, only the tracing buffer for CPU 2 was swapped with
 283           the main tracing buffer, and the other CPU buffers remain the same.
 284
 285           When this is enabled, this adds a little more overhead to the
 286           trace recording, as it needs to add some checks to synchronize
 287           recording with swaps. But this does not affect the performance
 288           of the overall system. This is enabled by default when the preempt
 289           or irq latency tracers are enabled, as those need to swap as well
 290           and already adds the overhead (plus a lot more).
 291
 292 config TRACE_BRANCH_PROFILING
 293         bool
 294         select GENERIC_TRACER
 295
 296 choice
 297         prompt "Branch Profiling"
 298         default BRANCH_PROFILE_NONE
 299         help
 300          The branch profiling is a software profiler. It will add hooks
 301          into the C conditionals to test which path a branch takes.
 302
 303          The likely/unlikely profiler only looks at the conditions that
 304          are annotated with a likely or unlikely macro.
 305
 306          The "all branch" profiler will profile every if-statement in the
 307          kernel. This profiler will also enable the likely/unlikely
 308          profiler.
 309
 310          Either of the above profilers adds a bit of overhead to the system.
 311          If unsure, choose "No branch profiling".
 312
 313 config BRANCH_PROFILE_NONE
 314         bool "No branch profiling"
 315         help
 316           No branch profiling. Branch profiling adds a bit of overhead.
 317           Only enable it if you want to analyse the branching behavior.
 318           Otherwise keep it disabled.
 319
 320 config PROFILE_ANNOTATED_BRANCHES
 321         bool "Trace likely/unlikely profiler"
 322         select TRACE_BRANCH_PROFILING
 323         help
 324           This tracer profiles all likely and unlikely macros
 325           in the kernel. It will display the results in:
 326
 327           /sys/kernel/debug/tracing/trace_stat/branch_annotated
 328
 329           Note: this will add a significant overhead; only turn this
 330           on if you need to profile the system's use of these macros.
 331
 332 config PROFILE_ALL_BRANCHES
 333         bool "Profile all if conditionals"
 334         select TRACE_BRANCH_PROFILING
 335         help
 336           This tracer profiles all branch conditions. Every if ()
 337           taken in the kernel is recorded whether it hit or miss.
 338           The results will be displayed in:
 339
 340           /sys/kernel/debug/tracing/trace_stat/branch_all
 341
 342           This option also enables the likely/unlikely profiler.
 343
 344           This configuration, when enabled, will impose a great overhead
 345           on the system. This should only be enabled when the system
 346           is to be analyzed in much detail.
 347 endchoice
 348
 349 config TRACING_BRANCHES
 350         bool
 351         help
 352           Selected by tracers that will trace the likely and unlikely
 353           conditions. This prevents the tracers themselves from being
 354           profiled. Profiling the tracing infrastructure can only happen
 355           when the likelys and unlikelys are not being traced.
 356
 357 config BRANCH_TRACER
 358         bool "Trace likely/unlikely instances"
 359         depends on TRACE_BRANCH_PROFILING
 360         select TRACING_BRANCHES
 361         help
 362           This traces the events of likely and unlikely condition
 363           calls in the kernel.  The difference between this and the
 364           "Trace likely/unlikely profiler" is that this is not a
 365           histogram of the callers, but actually places the calling
 366           events into a running trace buffer to see when and where the
 367           events happened, as well as their results.
 368
 369           Say N if unsure.
 370
 371 config STACK_TRACER
 372         bool "Trace max stack"
 373         depends on HAVE_FUNCTION_TRACER
 374         select FUNCTION_TRACER
 375         select STACKTRACE
 376         select KALLSYMS
 377         help
 378           This special tracer records the maximum stack footprint of the
 379           kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 380
 381           This tracer works by hooking into every function call that the
 382           kernel executes, and keeping a maximum stack depth value and
 383           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 384           then it will not have any overhead while the stack tracer
 385           is disabled.
 386
 387           To enable the stack tracer on bootup, pass in 'stacktrace'
 388           on the kernel command line.
 389
 390           The stack tracer can also be enabled or disabled via the
 391           sysctl kernel.stack_tracer_enabled
 392
 393           Say N if unsure.
 394
 395 config BLK_DEV_IO_TRACE
 396         bool "Support for tracing block IO actions"
 397         depends on SYSFS
 398         depends on BLOCK
 399         select RELAY
 400         select DEBUG_FS
 401         select TRACEPOINTS
 402         select GENERIC_TRACER
 403         select STACKTRACE
 404         help
 405           Say Y here if you want to be able to trace the block layer actions
 406           on a given queue. Tracing allows you to see any traffic happening
 407           on a block device queue. For more information (and the userspace
 408           support tools needed), fetch the blktrace tools from:
 409
 410           git://git.kernel.dk/blktrace.git
 411
 412           Tracing also is possible using the ftrace interface, e.g.:
 413
 414             echo 1 > /sys/block/sda/sda1/trace/enable
 415             echo blk > /sys/kernel/debug/tracing/current_tracer
 416             cat /sys/kernel/debug/tracing/trace_pipe
 417
 418           If unsure, say N.
 419
 420 config KPROBE_EVENT
 421         depends on KPROBES
 422         depends on HAVE_REGS_AND_STACK_ACCESS_API
 423         bool "Enable kprobes-based dynamic events"
 424         select TRACING
 425         select PROBE_EVENTS
 426         default y
 427         help
 428           This allows the user to add tracing events (similar to tracepoints)
 429           on the fly via the ftrace interface. See
 430           Documentation/trace/kprobetrace.txt for more details.
 431
 432           Those events can be inserted wherever kprobes can probe, and record
 433           various register and memory values.
 434
 435           This option is also required by perf-probe subcommand of perf tools.
 436           If you want to use perf tools, this option is strongly recommended.
 437
 438 config UPROBE_EVENT
 439         bool "Enable uprobes-based dynamic events"
 440         depends on ARCH_SUPPORTS_UPROBES
 441         depends on MMU
 442         select UPROBES
 443         select PROBE_EVENTS
 444         select TRACING
 445         default n
 446         help
 447           This allows the user to add tracing events on top of userspace
 448           dynamic events (similar to tracepoints) on the fly via the trace
 449           events interface. Those events can be inserted wherever uprobes
 450           can probe, and record various registers.
 451           This option is required if you plan to use perf-probe subcommand
 452           of perf tools on user space applications.
 453
 454 config PROBE_EVENTS
 455         def_bool n
 456
 457 config DYNAMIC_FTRACE
 458         bool "enable/disable function tracing dynamically"
 459         depends on FUNCTION_TRACER
 460         depends on HAVE_DYNAMIC_FTRACE
 461         default y
 462         help
 463           This option will modify all the calls to function tracing
 464           dynamically (will patch them out of the binary image and
 465           replace them with a No-Op instruction) on boot up. During
 466           compile time, a table is made of all the locations that ftrace
 467           can function trace, and this table is linked into the kernel
 468           image. When this is enabled, functions can be individually
 469           enabled, and the functions not enabled will not affect
 470           performance of the system.
 471
 472           See the files in /sys/kernel/debug/tracing:
 473             available_filter_functions
 474             set_ftrace_filter
 475             set_ftrace_notrace
 476
 477           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 478           otherwise has native performance as long as no tracing is active.
 479
 480 config DYNAMIC_FTRACE_WITH_REGS
 481         def_bool y
 482         depends on DYNAMIC_FTRACE
 483         depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
 484
 485 config FUNCTION_PROFILER
 486         bool "Kernel function profiler"
 487         depends on FUNCTION_TRACER
 488         default n
 489         help
 490           This option enables the kernel function profiler. A file is created
 491           in debugfs called function_profile_enabled which defaults to zero.
 492           When a 1 is echoed into this file profiling begins, and when a
 493           zero is entered, profiling stops. A "functions" file is created in
 494           the trace_stats directory; this file shows the list of functions that
 495           have been hit and their counters.
 496
 497           If in doubt, say N.
 498
 499 config FTRACE_MCOUNT_RECORD
 500         def_bool y
 501         depends on DYNAMIC_FTRACE
 502         depends on HAVE_FTRACE_MCOUNT_RECORD
 503
 504 config FTRACE_SELFTEST
 505         bool
 506
 507 config FTRACE_STARTUP_TEST
 508         bool "Perform a startup test on ftrace"
 509         depends on GENERIC_TRACER
 510         select FTRACE_SELFTEST
 511         help
 512           This option performs a series of startup tests on ftrace. On bootup
 513           a series of tests are made to verify that the tracer is
 514           functioning properly. It will do tests on all the configured
 515           tracers of ftrace.
 516
 517 config EVENT_TRACE_TEST_SYSCALLS
 518         bool "Run selftest on syscall events"
 519         depends on FTRACE_STARTUP_TEST
 520         help
 521          This option will also enable testing every syscall event.
 522          It only enables the event and disables it and runs various loads
 523          with the event enabled. This adds a bit more time for kernel boot
 524          up since it runs this on every system call defined.
 525
 526          TBD - enable a way to actually call the syscalls as we test their
 527                events
 528
 529 config MMIOTRACE
 530         bool "Memory mapped IO tracing"
 531         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 532         select GENERIC_TRACER
 533         help
 534           Mmiotrace traces Memory Mapped I/O access and is meant for
 535           debugging and reverse engineering. It is called from the ioremap
 536           implementation and works via page faults. Tracing is disabled by
 537           default and can be enabled at run-time.
 538
 539           See Documentation/trace/mmiotrace.txt.
 540           If you are not helping to develop drivers, say N.
 541
 542 config MMIOTRACE_TEST
 543         tristate "Test module for mmiotrace"
 544         depends on MMIOTRACE && m
 545         help
 546           This is a dumb module for testing mmiotrace. It is very dangerous
 547           as it will write garbage to IO memory starting at a given address.
 548           However, it should be safe to use on e.g. unused portion of VRAM.
 549
 550           Say N, unless you absolutely know what you are doing.
 551
 552 config RING_BUFFER_BENCHMARK
 553         tristate "Ring buffer benchmark stress tester"
 554         depends on RING_BUFFER
 555         help
 556           This option creates a test to stress the ring buffer and benchmark it.
 557           It creates its own ring buffer such that it will not interfere with
 558           any other users of the ring buffer (such as ftrace). It then creates
 559           a producer and consumer that will run for 10 seconds and sleep for
 560           10 seconds. Each interval it will print out the number of events
 561           it recorded and give a rough estimate of how long each iteration took.
 562
 563           It does not disable interrupts or raise its priority, so it may be
 564           affected by processes that are running.
 565
 566           If unsure, say N.
 567
 568 endif # FTRACE
 569
 570 endif # TRACING_SUPPORT
 571