linux/kernel/trace/Kconfig
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   1#
   2# Architectures that offer an FUNCTION_TRACER implementation should
   3#  select HAVE_FUNCTION_TRACER:
   4#
   5
   6config USER_STACKTRACE_SUPPORT
   7        bool
   8
   9config NOP_TRACER
  10        bool
  11
  12config HAVE_FTRACE_NMI_ENTER
  13        bool
  14        help
  15          See Documentation/trace/ftrace-design.txt
  16
  17config HAVE_FUNCTION_TRACER
  18        bool
  19        help
  20          See Documentation/trace/ftrace-design.txt
  21
  22config HAVE_FUNCTION_GRAPH_TRACER
  23        bool
  24        help
  25          See Documentation/trace/ftrace-design.txt
  26
  27config HAVE_FUNCTION_GRAPH_FP_TEST
  28        bool
  29        help
  30          See Documentation/trace/ftrace-design.txt
  31
  32config HAVE_FUNCTION_TRACE_MCOUNT_TEST
  33        bool
  34        help
  35          See Documentation/trace/ftrace-design.txt
  36
  37config HAVE_DYNAMIC_FTRACE
  38        bool
  39        help
  40          See Documentation/trace/ftrace-design.txt
  41
  42config HAVE_FTRACE_MCOUNT_RECORD
  43        bool
  44        help
  45          See Documentation/trace/ftrace-design.txt
  46
  47config HAVE_SYSCALL_TRACEPOINTS
  48        bool
  49        help
  50          See Documentation/trace/ftrace-design.txt
  51
  52config HAVE_C_RECORDMCOUNT
  53        bool
  54        help
  55          C version of recordmcount available?
  56
  57config TRACER_MAX_TRACE
  58        bool
  59
  60config RING_BUFFER
  61        bool
  62
  63config FTRACE_NMI_ENTER
  64       bool
  65       depends on HAVE_FTRACE_NMI_ENTER
  66       default y
  67
  68config EVENT_TRACING
  69        select CONTEXT_SWITCH_TRACER
  70        bool
  71
  72config EVENT_POWER_TRACING_DEPRECATED
  73        depends on EVENT_TRACING
  74        bool "Deprecated power event trace API, to be removed"
  75        default y
  76        help
  77          Provides old power event types:
  78          C-state/idle accounting events:
  79          power:power_start
  80          power:power_end
  81          and old cpufreq accounting event:
  82          power:power_frequency
  83          This is for userspace compatibility
  84          and will vanish after 5 kernel iterations,
  85          namely 3.1.
  86
  87config CONTEXT_SWITCH_TRACER
  88        bool
  89
  90config RING_BUFFER_ALLOW_SWAP
  91        bool
  92        help
  93         Allow the use of ring_buffer_swap_cpu.
  94         Adds a very slight overhead to tracing when enabled.
  95
  96# All tracer options should select GENERIC_TRACER. For those options that are
  97# enabled by all tracers (context switch and event tracer) they select TRACING.
  98# This allows those options to appear when no other tracer is selected. But the
  99# options do not appear when something else selects it. We need the two options
 100# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
 101# hiding of the automatic options.
 102
 103config TRACING
 104        bool
 105        select DEBUG_FS
 106        select RING_BUFFER
 107        select STACKTRACE if STACKTRACE_SUPPORT
 108        select TRACEPOINTS
 109        select NOP_TRACER
 110        select BINARY_PRINTF
 111        select EVENT_TRACING
 112
 113config GENERIC_TRACER
 114        bool
 115        select TRACING
 116
 117#
 118# Minimum requirements an architecture has to meet for us to
 119# be able to offer generic tracing facilities:
 120#
 121config TRACING_SUPPORT
 122        bool
 123        # PPC32 has no irqflags tracing support, but it can use most of the
 124        # tracers anyway, they were tested to build and work. Note that new
 125        # exceptions to this list aren't welcomed, better implement the
 126        # irqflags tracing for your architecture.
 127        depends on TRACE_IRQFLAGS_SUPPORT || PPC32
 128        depends on STACKTRACE_SUPPORT
 129        default y
 130
 131if TRACING_SUPPORT
 132
 133menuconfig FTRACE
 134        bool "Tracers"
 135        default y if DEBUG_KERNEL
 136        help
 137          Enable the kernel tracing infrastructure.
 138
 139if FTRACE
 140
 141config FUNCTION_TRACER
 142        bool "Kernel Function Tracer"
 143        depends on HAVE_FUNCTION_TRACER
 144        select KALLSYMS
 145        select GENERIC_TRACER
 146        select CONTEXT_SWITCH_TRACER
 147        help
 148          Enable the kernel to trace every kernel function. This is done
 149          by using a compiler feature to insert a small, 5-byte No-Operation
 150          instruction at the beginning of every kernel function, which NOP
 151          sequence is then dynamically patched into a tracer call when
 152          tracing is enabled by the administrator. If it's runtime disabled
 153          (the bootup default), then the overhead of the instructions is very
 154          small and not measurable even in micro-benchmarks.
 155
 156config FUNCTION_GRAPH_TRACER
 157        bool "Kernel Function Graph Tracer"
 158        depends on HAVE_FUNCTION_GRAPH_TRACER
 159        depends on FUNCTION_TRACER
 160        depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 161        default y
 162        help
 163          Enable the kernel to trace a function at both its return
 164          and its entry.
 165          Its first purpose is to trace the duration of functions and
 166          draw a call graph for each thread with some information like
 167          the return value. This is done by setting the current return
 168          address on the current task structure into a stack of calls.
 169
 170
 171config IRQSOFF_TRACER
 172        bool "Interrupts-off Latency Tracer"
 173        default n
 174        depends on TRACE_IRQFLAGS_SUPPORT
 175        depends on !ARCH_USES_GETTIMEOFFSET
 176        select TRACE_IRQFLAGS
 177        select GENERIC_TRACER
 178        select TRACER_MAX_TRACE
 179        select RING_BUFFER_ALLOW_SWAP
 180        help
 181          This option measures the time spent in irqs-off critical
 182          sections, with microsecond accuracy.
 183
 184          The default measurement method is a maximum search, which is
 185          disabled by default and can be runtime (re-)started
 186          via:
 187
 188              echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 189
 190          (Note that kernel size and overhead increase with this option
 191          enabled. This option and the preempt-off timing option can be
 192          used together or separately.)
 193
 194config PREEMPT_TRACER
 195        bool "Preemption-off Latency Tracer"
 196        default n
 197        depends on !ARCH_USES_GETTIMEOFFSET
 198        depends on PREEMPT
 199        select GENERIC_TRACER
 200        select TRACER_MAX_TRACE
 201        select RING_BUFFER_ALLOW_SWAP
 202        help
 203          This option measures the time spent in preemption-off critical
 204          sections, with microsecond accuracy.
 205
 206          The default measurement method is a maximum search, which is
 207          disabled by default and can be runtime (re-)started
 208          via:
 209
 210              echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 211
 212          (Note that kernel size and overhead increase with this option
 213          enabled. This option and the irqs-off timing option can be
 214          used together or separately.)
 215
 216config SCHED_TRACER
 217        bool "Scheduling Latency Tracer"
 218        select GENERIC_TRACER
 219        select CONTEXT_SWITCH_TRACER
 220        select TRACER_MAX_TRACE
 221        help
 222          This tracer tracks the latency of the highest priority task
 223          to be scheduled in, starting from the point it has woken up.
 224
 225config ENABLE_DEFAULT_TRACERS
 226        bool "Trace process context switches and events"
 227        depends on !GENERIC_TRACER
 228        select TRACING
 229        help
 230          This tracer hooks to various trace points in the kernel,
 231          allowing the user to pick and choose which trace point they
 232          want to trace. It also includes the sched_switch tracer plugin.
 233
 234config FTRACE_SYSCALLS
 235        bool "Trace syscalls"
 236        depends on HAVE_SYSCALL_TRACEPOINTS
 237        select GENERIC_TRACER
 238        select KALLSYMS
 239        help
 240          Basic tracer to catch the syscall entry and exit events.
 241
 242config TRACE_BRANCH_PROFILING
 243        bool
 244        select GENERIC_TRACER
 245
 246choice
 247        prompt "Branch Profiling"
 248        default BRANCH_PROFILE_NONE
 249        help
 250         The branch profiling is a software profiler. It will add hooks
 251         into the C conditionals to test which path a branch takes.
 252
 253         The likely/unlikely profiler only looks at the conditions that
 254         are annotated with a likely or unlikely macro.
 255
 256         The "all branch" profiler will profile every if-statement in the
 257         kernel. This profiler will also enable the likely/unlikely
 258         profiler.
 259
 260         Either of the above profilers adds a bit of overhead to the system.
 261         If unsure, choose "No branch profiling".
 262
 263config BRANCH_PROFILE_NONE
 264        bool "No branch profiling"
 265        help
 266          No branch profiling. Branch profiling adds a bit of overhead.
 267          Only enable it if you want to analyse the branching behavior.
 268          Otherwise keep it disabled.
 269
 270config PROFILE_ANNOTATED_BRANCHES
 271        bool "Trace likely/unlikely profiler"
 272        select TRACE_BRANCH_PROFILING
 273        help
 274          This tracer profiles all likely and unlikely macros
 275          in the kernel. It will display the results in:
 276
 277          /sys/kernel/debug/tracing/trace_stat/branch_annotated
 278
 279          Note: this will add a significant overhead; only turn this
 280          on if you need to profile the system's use of these macros.
 281
 282config PROFILE_ALL_BRANCHES
 283        bool "Profile all if conditionals"
 284        select TRACE_BRANCH_PROFILING
 285        help
 286          This tracer profiles all branch conditions. Every if ()
 287          taken in the kernel is recorded whether it hit or miss.
 288          The results will be displayed in:
 289
 290          /sys/kernel/debug/tracing/trace_stat/branch_all
 291
 292          This option also enables the likely/unlikely profiler.
 293
 294          This configuration, when enabled, will impose a great overhead
 295          on the system. This should only be enabled when the system
 296          is to be analyzed in much detail.
 297endchoice
 298
 299config TRACING_BRANCHES
 300        bool
 301        help
 302          Selected by tracers that will trace the likely and unlikely
 303          conditions. This prevents the tracers themselves from being
 304          profiled. Profiling the tracing infrastructure can only happen
 305          when the likelys and unlikelys are not being traced.
 306
 307config BRANCH_TRACER
 308        bool "Trace likely/unlikely instances"
 309        depends on TRACE_BRANCH_PROFILING
 310        select TRACING_BRANCHES
 311        help
 312          This traces the events of likely and unlikely condition
 313          calls in the kernel.  The difference between this and the
 314          "Trace likely/unlikely profiler" is that this is not a
 315          histogram of the callers, but actually places the calling
 316          events into a running trace buffer to see when and where the
 317          events happened, as well as their results.
 318
 319          Say N if unsure.
 320
 321config STACK_TRACER
 322        bool "Trace max stack"
 323        depends on HAVE_FUNCTION_TRACER
 324        select FUNCTION_TRACER
 325        select STACKTRACE
 326        select KALLSYMS
 327        help
 328          This special tracer records the maximum stack footprint of the
 329          kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 330
 331          This tracer works by hooking into every function call that the
 332          kernel executes, and keeping a maximum stack depth value and
 333          stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 334          then it will not have any overhead while the stack tracer
 335          is disabled.
 336
 337          To enable the stack tracer on bootup, pass in 'stacktrace'
 338          on the kernel command line.
 339
 340          The stack tracer can also be enabled or disabled via the
 341          sysctl kernel.stack_tracer_enabled
 342
 343          Say N if unsure.
 344
 345config BLK_DEV_IO_TRACE
 346        bool "Support for tracing block IO actions"
 347        depends on SYSFS
 348        depends on BLOCK
 349        select RELAY
 350        select DEBUG_FS
 351        select TRACEPOINTS
 352        select GENERIC_TRACER
 353        select STACKTRACE
 354        help
 355          Say Y here if you want to be able to trace the block layer actions
 356          on a given queue. Tracing allows you to see any traffic happening
 357          on a block device queue. For more information (and the userspace
 358          support tools needed), fetch the blktrace tools from:
 359
 360          git://git.kernel.dk/blktrace.git
 361
 362          Tracing also is possible using the ftrace interface, e.g.:
 363
 364            echo 1 > /sys/block/sda/sda1/trace/enable
 365            echo blk > /sys/kernel/debug/tracing/current_tracer
 366            cat /sys/kernel/debug/tracing/trace_pipe
 367
 368          If unsure, say N.
 369
 370config KPROBE_EVENT
 371        depends on KPROBES
 372        depends on HAVE_REGS_AND_STACK_ACCESS_API
 373        bool "Enable kprobes-based dynamic events"
 374        select TRACING
 375        select PROBE_EVENTS
 376        default y
 377        help
 378          This allows the user to add tracing events (similar to tracepoints)
 379          on the fly via the ftrace interface. See
 380          Documentation/trace/kprobetrace.txt for more details.
 381
 382          Those events can be inserted wherever kprobes can probe, and record
 383          various register and memory values.
 384
 385          This option is also required by perf-probe subcommand of perf tools.
 386          If you want to use perf tools, this option is strongly recommended.
 387
 388config UPROBE_EVENT
 389        bool "Enable uprobes-based dynamic events"
 390        depends on ARCH_SUPPORTS_UPROBES
 391        depends on MMU
 392        select UPROBES
 393        select PROBE_EVENTS
 394        select TRACING
 395        default n
 396        help
 397          This allows the user to add tracing events on top of userspace
 398          dynamic events (similar to tracepoints) on the fly via the trace
 399          events interface. Those events can be inserted wherever uprobes
 400          can probe, and record various registers.
 401          This option is required if you plan to use perf-probe subcommand
 402          of perf tools on user space applications.
 403
 404config PROBE_EVENTS
 405        def_bool n
 406
 407config DYNAMIC_FTRACE
 408        bool "enable/disable ftrace tracepoints dynamically"
 409        depends on FUNCTION_TRACER
 410        depends on HAVE_DYNAMIC_FTRACE
 411        default y
 412        help
 413          This option will modify all the calls to ftrace dynamically
 414          (will patch them out of the binary image and replace them
 415          with a No-Op instruction) as they are called. A table is
 416          created to dynamically enable them again.
 417
 418          This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 419          otherwise has native performance as long as no tracing is active.
 420
 421          The changes to the code are done by a kernel thread that
 422          wakes up once a second and checks to see if any ftrace calls
 423          were made. If so, it runs stop_machine (stops all CPUS)
 424          and modifies the code to jump over the call to ftrace.
 425
 426config FUNCTION_PROFILER
 427        bool "Kernel function profiler"
 428        depends on FUNCTION_TRACER
 429        default n
 430        help
 431          This option enables the kernel function profiler. A file is created
 432          in debugfs called function_profile_enabled which defaults to zero.
 433          When a 1 is echoed into this file profiling begins, and when a
 434          zero is entered, profiling stops. A "functions" file is created in
 435          the trace_stats directory; this file shows the list of functions that
 436          have been hit and their counters.
 437
 438          If in doubt, say N.
 439
 440config FTRACE_MCOUNT_RECORD
 441        def_bool y
 442        depends on DYNAMIC_FTRACE
 443        depends on HAVE_FTRACE_MCOUNT_RECORD
 444
 445config FTRACE_SELFTEST
 446        bool
 447
 448config FTRACE_STARTUP_TEST
 449        bool "Perform a startup test on ftrace"
 450        depends on GENERIC_TRACER
 451        select FTRACE_SELFTEST
 452        help
 453          This option performs a series of startup tests on ftrace. On bootup
 454          a series of tests are made to verify that the tracer is
 455          functioning properly. It will do tests on all the configured
 456          tracers of ftrace.
 457
 458config EVENT_TRACE_TEST_SYSCALLS
 459        bool "Run selftest on syscall events"
 460        depends on FTRACE_STARTUP_TEST
 461        help
 462         This option will also enable testing every syscall event.
 463         It only enables the event and disables it and runs various loads
 464         with the event enabled. This adds a bit more time for kernel boot
 465         up since it runs this on every system call defined.
 466
 467         TBD - enable a way to actually call the syscalls as we test their
 468               events
 469
 470config MMIOTRACE
 471        bool "Memory mapped IO tracing"
 472        depends on HAVE_MMIOTRACE_SUPPORT && PCI
 473        select GENERIC_TRACER
 474        help
 475          Mmiotrace traces Memory Mapped I/O access and is meant for
 476          debugging and reverse engineering. It is called from the ioremap
 477          implementation and works via page faults. Tracing is disabled by
 478          default and can be enabled at run-time.
 479
 480          See Documentation/trace/mmiotrace.txt.
 481          If you are not helping to develop drivers, say N.
 482
 483config MMIOTRACE_TEST
 484        tristate "Test module for mmiotrace"
 485        depends on MMIOTRACE && m
 486        help
 487          This is a dumb module for testing mmiotrace. It is very dangerous
 488          as it will write garbage to IO memory starting at a given address.
 489          However, it should be safe to use on e.g. unused portion of VRAM.
 490
 491          Say N, unless you absolutely know what you are doing.
 492
 493config RING_BUFFER_BENCHMARK
 494        tristate "Ring buffer benchmark stress tester"
 495        depends on RING_BUFFER
 496        help
 497          This option creates a test to stress the ring buffer and benchmark it.
 498          It creates its own ring buffer such that it will not interfere with
 499          any other users of the ring buffer (such as ftrace). It then creates
 500          a producer and consumer that will run for 10 seconds and sleep for
 501          10 seconds. Each interval it will print out the number of events
 502          it recorded and give a rough estimate of how long each iteration took.
 503
 504          It does not disable interrupts or raise its priority, so it may be
 505          affected by processes that are running.
 506
 507          If unsure, say N.
 508
 509endif # FTRACE
 510
 511endif # TRACING_SUPPORT
 512
 513
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