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 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
  87 config CONTEXT_SWITCH_TRACER
  88         bool
  89
  90 config 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
 103 config 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
 113 config 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 #
 121 config 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
 131 if TRACING_SUPPORT
 132
 133 menuconfig FTRACE
 134         bool "Tracers"
 135         default y if DEBUG_KERNEL
 136         help
 137           Enable the kernel tracing infrastructure.
 138
 139 if FTRACE
 140
 141 config 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
 156 config 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
 171 config 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
 194 config 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
 216 config 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
 225 config 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
 234 config 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
 242 config TRACE_BRANCH_PROFILING
 243         bool
 244         select GENERIC_TRACER
 245
 246 choice
 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
 263 config 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
 270 config 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
 282 config 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.
 297 endchoice
 298
 299 config 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
 307 config 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
 321 config 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
 345 config 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
 370 config 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
 388 config 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
 404 config PROBE_EVENTS
 405         def_bool n
 406
 407 config 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
 426 config 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
 440 config FTRACE_MCOUNT_RECORD
 441         def_bool y
 442         depends on DYNAMIC_FTRACE
 443         depends on HAVE_FTRACE_MCOUNT_RECORD
 444
 445 config FTRACE_SELFTEST
 446         bool
 447
 448 config 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
 458 config 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
 470 config 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
 483 config 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
 493 config 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
 509 endif # FTRACE
 510
 511 endif # TRACING_SUPPORT
 512