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