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         help
 195           This option measures the time spent in irqs-off critical
 196           sections, with microsecond accuracy.
 197
 198           The default measurement method is a maximum search, which is
 199           disabled by default and can be runtime (re-)started
 200           via:
 201
 202               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 203
 204           (Note that kernel size and overhead increase with this option
 205           enabled. This option and the preempt-off timing option can be
 206           used together or separately.)
 207
 208 config PREEMPT_TRACER
 209         bool "Preemption-off Latency Tracer"
 210         default n
 211         depends on !ARCH_USES_GETTIMEOFFSET
 212         depends on PREEMPT
 213         select GENERIC_TRACER
 214         select TRACER_MAX_TRACE
 215         select RING_BUFFER_ALLOW_SWAP
 216         help
 217           This option measures the time spent in preemption-off critical
 218           sections, with microsecond accuracy.
 219
 220           The default measurement method is a maximum search, which is
 221           disabled by default and can be runtime (re-)started
 222           via:
 223
 224               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 225
 226           (Note that kernel size and overhead increase with this option
 227           enabled. This option and the irqs-off timing option can be
 228           used together or separately.)
 229
 230 config SCHED_TRACER
 231         bool "Scheduling Latency Tracer"
 232         select GENERIC_TRACER
 233         select CONTEXT_SWITCH_TRACER
 234         select TRACER_MAX_TRACE
 235         help
 236           This tracer tracks the latency of the highest priority task
 237           to be scheduled in, starting from the point it has woken up.
 238
 239 config ENABLE_DEFAULT_TRACERS
 240         bool "Trace process context switches and events"
 241         depends on !GENERIC_TRACER
 242         select TRACING
 243         help
 244           This tracer hooks to various trace points in the kernel,
 245           allowing the user to pick and choose which trace point they
 246           want to trace. It also includes the sched_switch tracer plugin.
 247
 248 config FTRACE_SYSCALLS
 249         bool "Trace syscalls"
 250         depends on HAVE_SYSCALL_TRACEPOINTS
 251         select GENERIC_TRACER
 252         select KALLSYMS
 253         help
 254           Basic tracer to catch the syscall entry and exit events.
 255
 256 config TRACE_BRANCH_PROFILING
 257         bool
 258         select GENERIC_TRACER
 259
 260 choice
 261         prompt "Branch Profiling"
 262         default BRANCH_PROFILE_NONE
 263         help
 264          The branch profiling is a software profiler. It will add hooks
 265          into the C conditionals to test which path a branch takes.
 266
 267          The likely/unlikely profiler only looks at the conditions that
 268          are annotated with a likely or unlikely macro.
 269
 270          The "all branch" profiler will profile every if-statement in the
 271          kernel. This profiler will also enable the likely/unlikely
 272          profiler.
 273
 274          Either of the above profilers adds a bit of overhead to the system.
 275          If unsure, choose "No branch profiling".
 276
 277 config BRANCH_PROFILE_NONE
 278         bool "No branch profiling"
 279         help
 280           No branch profiling. Branch profiling adds a bit of overhead.
 281           Only enable it if you want to analyse the branching behavior.
 282           Otherwise keep it disabled.
 283
 284 config PROFILE_ANNOTATED_BRANCHES
 285         bool "Trace likely/unlikely profiler"
 286         select TRACE_BRANCH_PROFILING
 287         help
 288           This tracer profiles all likely and unlikely macros
 289           in the kernel. It will display the results in:
 290
 291           /sys/kernel/debug/tracing/trace_stat/branch_annotated
 292
 293           Note: this will add a significant overhead; only turn this
 294           on if you need to profile the system's use of these macros.
 295
 296 config PROFILE_ALL_BRANCHES
 297         bool "Profile all if conditionals"
 298         select TRACE_BRANCH_PROFILING
 299         help
 300           This tracer profiles all branch conditions. Every if ()
 301           taken in the kernel is recorded whether it hit or miss.
 302           The results will be displayed in:
 303
 304           /sys/kernel/debug/tracing/trace_stat/branch_all
 305
 306           This option also enables the likely/unlikely profiler.
 307
 308           This configuration, when enabled, will impose a great overhead
 309           on the system. This should only be enabled when the system
 310           is to be analyzed in much detail.
 311 endchoice
 312
 313 config TRACING_BRANCHES
 314         bool
 315         help
 316           Selected by tracers that will trace the likely and unlikely
 317           conditions. This prevents the tracers themselves from being
 318           profiled. Profiling the tracing infrastructure can only happen
 319           when the likelys and unlikelys are not being traced.
 320
 321 config BRANCH_TRACER
 322         bool "Trace likely/unlikely instances"
 323         depends on TRACE_BRANCH_PROFILING
 324         select TRACING_BRANCHES
 325         help
 326           This traces the events of likely and unlikely condition
 327           calls in the kernel.  The difference between this and the
 328           "Trace likely/unlikely profiler" is that this is not a
 329           histogram of the callers, but actually places the calling
 330           events into a running trace buffer to see when and where the
 331           events happened, as well as their results.
 332
 333           Say N if unsure.
 334
 335 config STACK_TRACER
 336         bool "Trace max stack"
 337         depends on HAVE_FUNCTION_TRACER
 338         select FUNCTION_TRACER
 339         select STACKTRACE
 340         select KALLSYMS
 341         help
 342           This special tracer records the maximum stack footprint of the
 343           kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 344
 345           This tracer works by hooking into every function call that the
 346           kernel executes, and keeping a maximum stack depth value and
 347           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 348           then it will not have any overhead while the stack tracer
 349           is disabled.
 350
 351           To enable the stack tracer on bootup, pass in 'stacktrace'
 352           on the kernel command line.
 353
 354           The stack tracer can also be enabled or disabled via the
 355           sysctl kernel.stack_tracer_enabled
 356
 357           Say N if unsure.
 358
 359 config BLK_DEV_IO_TRACE
 360         bool "Support for tracing block IO actions"
 361         depends on SYSFS
 362         depends on BLOCK
 363         select RELAY
 364         select DEBUG_FS
 365         select TRACEPOINTS
 366         select GENERIC_TRACER
 367         select STACKTRACE
 368         help
 369           Say Y here if you want to be able to trace the block layer actions
 370           on a given queue. Tracing allows you to see any traffic happening
 371           on a block device queue. For more information (and the userspace
 372           support tools needed), fetch the blktrace tools from:
 373
 374           git://git.kernel.dk/blktrace.git
 375
 376           Tracing also is possible using the ftrace interface, e.g.:
 377
 378             echo 1 > /sys/block/sda/sda1/trace/enable
 379             echo blk > /sys/kernel/debug/tracing/current_tracer
 380             cat /sys/kernel/debug/tracing/trace_pipe
 381
 382           If unsure, say N.
 383
 384 config KPROBE_EVENT
 385         depends on KPROBES
 386         depends on HAVE_REGS_AND_STACK_ACCESS_API
 387         bool "Enable kprobes-based dynamic events"
 388         select TRACING
 389         select PROBE_EVENTS
 390         default y
 391         help
 392           This allows the user to add tracing events (similar to tracepoints)
 393           on the fly via the ftrace interface. See
 394           Documentation/trace/kprobetrace.txt for more details.
 395
 396           Those events can be inserted wherever kprobes can probe, and record
 397           various register and memory values.
 398
 399           This option is also required by perf-probe subcommand of perf tools.
 400           If you want to use perf tools, this option is strongly recommended.
 401
 402 config UPROBE_EVENT
 403         bool "Enable uprobes-based dynamic events"
 404         depends on ARCH_SUPPORTS_UPROBES
 405         depends on MMU
 406         select UPROBES
 407         select PROBE_EVENTS
 408         select TRACING
 409         default n
 410         help
 411           This allows the user to add tracing events on top of userspace
 412           dynamic events (similar to tracepoints) on the fly via the trace
 413           events interface. Those events can be inserted wherever uprobes
 414           can probe, and record various registers.
 415           This option is required if you plan to use perf-probe subcommand
 416           of perf tools on user space applications.
 417
 418 config PROBE_EVENTS
 419         def_bool n
 420
 421 config DYNAMIC_FTRACE
 422         bool "enable/disable ftrace tracepoints dynamically"
 423         depends on FUNCTION_TRACER
 424         depends on HAVE_DYNAMIC_FTRACE
 425         default y
 426         help
 427           This option will modify all the calls to ftrace dynamically
 428           (will patch them out of the binary image and replace them
 429           with a No-Op instruction) as they are called. A table is
 430           created to dynamically enable them again.
 431
 432           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 433           otherwise has native performance as long as no tracing is active.
 434
 435           The changes to the code are done by a kernel thread that
 436           wakes up once a second and checks to see if any ftrace calls
 437           were made. If so, it runs stop_machine (stops all CPUS)
 438           and modifies the code to jump over the call to ftrace.
 439
 440 config DYNAMIC_FTRACE_WITH_REGS
 441         def_bool y
 442         depends on DYNAMIC_FTRACE
 443         depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
 444
 445 config FUNCTION_PROFILER
 446         bool "Kernel function profiler"
 447         depends on FUNCTION_TRACER
 448         default n
 449         help
 450           This option enables the kernel function profiler. A file is created
 451           in debugfs called function_profile_enabled which defaults to zero.
 452           When a 1 is echoed into this file profiling begins, and when a
 453           zero is entered, profiling stops. A "functions" file is created in
 454           the trace_stats directory; this file shows the list of functions that
 455           have been hit and their counters.
 456
 457           If in doubt, say N.
 458
 459 config FTRACE_MCOUNT_RECORD
 460         def_bool y
 461         depends on DYNAMIC_FTRACE
 462         depends on HAVE_FTRACE_MCOUNT_RECORD
 463
 464 config FTRACE_SELFTEST
 465         bool
 466
 467 config FTRACE_STARTUP_TEST
 468         bool "Perform a startup test on ftrace"
 469         depends on GENERIC_TRACER
 470         select FTRACE_SELFTEST
 471         help
 472           This option performs a series of startup tests on ftrace. On bootup
 473           a series of tests are made to verify that the tracer is
 474           functioning properly. It will do tests on all the configured
 475           tracers of ftrace.
 476
 477 config EVENT_TRACE_TEST_SYSCALLS
 478         bool "Run selftest on syscall events"
 479         depends on FTRACE_STARTUP_TEST
 480         help
 481          This option will also enable testing every syscall event.
 482          It only enables the event and disables it and runs various loads
 483          with the event enabled. This adds a bit more time for kernel boot
 484          up since it runs this on every system call defined.
 485
 486          TBD - enable a way to actually call the syscalls as we test their
 487                events
 488
 489 config MMIOTRACE
 490         bool "Memory mapped IO tracing"
 491         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 492         select GENERIC_TRACER
 493         help
 494           Mmiotrace traces Memory Mapped I/O access and is meant for
 495           debugging and reverse engineering. It is called from the ioremap
 496           implementation and works via page faults. Tracing is disabled by
 497           default and can be enabled at run-time.
 498
 499           See Documentation/trace/mmiotrace.txt.
 500           If you are not helping to develop drivers, say N.
 501
 502 config MMIOTRACE_TEST
 503         tristate "Test module for mmiotrace"
 504         depends on MMIOTRACE && m
 505         help
 506           This is a dumb module for testing mmiotrace. It is very dangerous
 507           as it will write garbage to IO memory starting at a given address.
 508           However, it should be safe to use on e.g. unused portion of VRAM.
 509
 510           Say N, unless you absolutely know what you are doing.
 511
 512 config RING_BUFFER_BENCHMARK
 513         tristate "Ring buffer benchmark stress tester"
 514         depends on RING_BUFFER
 515         help
 516           This option creates a test to stress the ring buffer and benchmark it.
 517           It creates its own ring buffer such that it will not interfere with
 518           any other users of the ring buffer (such as ftrace). It then creates
 519           a producer and consumer that will run for 10 seconds and sleep for
 520           10 seconds. Each interval it will print out the number of events
 521           it recorded and give a rough estimate of how long each iteration took.
 522
 523           It does not disable interrupts or raise its priority, so it may be
 524           affected by processes that are running.
 525
 526           If unsure, say N.
 527
 528 endif # FTRACE
 529
 530 endif # TRACING_SUPPORT
 531