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