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 FRAME_POINTER if !ARM_UNWIND && !S390 && !MICROBLAZE
 145         select KALLSYMS
 146         select GENERIC_TRACER
 147         select CONTEXT_SWITCH_TRACER
 148         help
 149           Enable the kernel to trace every kernel function. This is done
 150           by using a compiler feature to insert a small, 5-byte No-Operation
 151           instruction at the beginning of every kernel function, which NOP
 152           sequence is then dynamically patched into a tracer call when
 153           tracing is enabled by the administrator. If it's runtime disabled
 154           (the bootup default), then the overhead of the instructions is very
 155           small and not measurable even in micro-benchmarks.
 156
 157 config FUNCTION_GRAPH_TRACER
 158         bool "Kernel Function Graph Tracer"
 159         depends on HAVE_FUNCTION_GRAPH_TRACER
 160         depends on FUNCTION_TRACER
 161         depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 162         default y
 163         help
 164           Enable the kernel to trace a function at both its return
 165           and its entry.
 166           Its first purpose is to trace the duration of functions and
 167           draw a call graph for each thread with some information like
 168           the return value. This is done by setting the current return
 169           address on the current task structure into a stack of calls.
 170
 171
 172 config IRQSOFF_TRACER
 173         bool "Interrupts-off Latency Tracer"
 174         default n
 175         depends on TRACE_IRQFLAGS_SUPPORT
 176         depends on !ARCH_USES_GETTIMEOFFSET
 177         select TRACE_IRQFLAGS
 178         select GENERIC_TRACER
 179         select TRACER_MAX_TRACE
 180         select RING_BUFFER_ALLOW_SWAP
 181         help
 182           This option measures the time spent in irqs-off critical
 183           sections, with microsecond accuracy.
 184
 185           The default measurement method is a maximum search, which is
 186           disabled by default and can be runtime (re-)started
 187           via:
 188
 189               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 190
 191           (Note that kernel size and overhead increase with this option
 192           enabled. This option and the preempt-off timing option can be
 193           used together or separately.)
 194
 195 config PREEMPT_TRACER
 196         bool "Preemption-off Latency Tracer"
 197         default n
 198         depends on !ARCH_USES_GETTIMEOFFSET
 199         depends on PREEMPT
 200         select GENERIC_TRACER
 201         select TRACER_MAX_TRACE
 202         select RING_BUFFER_ALLOW_SWAP
 203         help
 204           This option measures the time spent in preemption-off critical
 205           sections, with microsecond accuracy.
 206
 207           The default measurement method is a maximum search, which is
 208           disabled by default and can be runtime (re-)started
 209           via:
 210
 211               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 212
 213           (Note that kernel size and overhead increase with this option
 214           enabled. This option and the irqs-off timing option can be
 215           used together or separately.)
 216
 217 config SCHED_TRACER
 218         bool "Scheduling Latency Tracer"
 219         select GENERIC_TRACER
 220         select CONTEXT_SWITCH_TRACER
 221         select TRACER_MAX_TRACE
 222         help
 223           This tracer tracks the latency of the highest priority task
 224           to be scheduled in, starting from the point it has woken up.
 225
 226 config ENABLE_DEFAULT_TRACERS
 227         bool "Trace process context switches and events"
 228         depends on !GENERIC_TRACER
 229         select TRACING
 230         help
 231           This tracer hooks to various trace points in the kernel,
 232           allowing the user to pick and choose which trace point they
 233           want to trace. It also includes the sched_switch tracer plugin.
 234
 235 config FTRACE_SYSCALLS
 236         bool "Trace syscalls"
 237         depends on HAVE_SYSCALL_TRACEPOINTS
 238         select GENERIC_TRACER
 239         select KALLSYMS
 240         help
 241           Basic tracer to catch the syscall entry and exit events.
 242
 243 config TRACE_BRANCH_PROFILING
 244         bool
 245         select GENERIC_TRACER
 246
 247 choice
 248         prompt "Branch Profiling"
 249         default BRANCH_PROFILE_NONE
 250         help
 251          The branch profiling is a software profiler. It will add hooks
 252          into the C conditionals to test which path a branch takes.
 253
 254          The likely/unlikely profiler only looks at the conditions that
 255          are annotated with a likely or unlikely macro.
 256
 257          The "all branch" profiler will profile every if-statement in the
 258          kernel. This profiler will also enable the likely/unlikely
 259          profiler.
 260
 261          Either of the above profilers adds a bit of overhead to the system.
 262          If unsure, choose "No branch profiling".
 263
 264 config BRANCH_PROFILE_NONE
 265         bool "No branch profiling"
 266         help
 267           No branch profiling. Branch profiling adds a bit of overhead.
 268           Only enable it if you want to analyse the branching behavior.
 269           Otherwise keep it disabled.
 270
 271 config PROFILE_ANNOTATED_BRANCHES
 272         bool "Trace likely/unlikely profiler"
 273         select TRACE_BRANCH_PROFILING
 274         help
 275           This tracer profiles all the the likely and unlikely macros
 276           in the kernel. It will display the results in:
 277
 278           /sys/kernel/debug/tracing/trace_stat/branch_annotated
 279
 280           Note: this will add a significant overhead; only turn this
 281           on if you need to profile the system's use of these macros.
 282
 283 config PROFILE_ALL_BRANCHES
 284         bool "Profile all if conditionals"
 285         select TRACE_BRANCH_PROFILING
 286         help
 287           This tracer profiles all branch conditions. Every if ()
 288           taken in the kernel is recorded whether it hit or miss.
 289           The results will be displayed in:
 290
 291           /sys/kernel/debug/tracing/trace_stat/branch_all
 292
 293           This option also enables the likely/unlikely profiler.
 294
 295           This configuration, when enabled, will impose a great overhead
 296           on the system. This should only be enabled when the system
 297           is to be analyzed in much detail.
 298 endchoice
 299
 300 config TRACING_BRANCHES
 301         bool
 302         help
 303           Selected by tracers that will trace the likely and unlikely
 304           conditions. This prevents the tracers themselves from being
 305           profiled. Profiling the tracing infrastructure can only happen
 306           when the likelys and unlikelys are not being traced.
 307
 308 config BRANCH_TRACER
 309         bool "Trace likely/unlikely instances"
 310         depends on TRACE_BRANCH_PROFILING
 311         select TRACING_BRANCHES
 312         help
 313           This traces the events of likely and unlikely condition
 314           calls in the kernel.  The difference between this and the
 315           "Trace likely/unlikely profiler" is that this is not a
 316           histogram of the callers, but actually places the calling
 317           events into a running trace buffer to see when and where the
 318           events happened, as well as their results.
 319
 320           Say N if unsure.
 321
 322 config STACK_TRACER
 323         bool "Trace max stack"
 324         depends on HAVE_FUNCTION_TRACER
 325         select FUNCTION_TRACER
 326         select STACKTRACE
 327         select KALLSYMS
 328         help
 329           This special tracer records the maximum stack footprint of the
 330           kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 331
 332           This tracer works by hooking into every function call that the
 333           kernel executes, and keeping a maximum stack depth value and
 334           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 335           then it will not have any overhead while the stack tracer
 336           is disabled.
 337
 338           To enable the stack tracer on bootup, pass in 'stacktrace'
 339           on the kernel command line.
 340
 341           The stack tracer can also be enabled or disabled via the
 342           sysctl kernel.stack_tracer_enabled
 343
 344           Say N if unsure.
 345
 346 config BLK_DEV_IO_TRACE
 347         bool "Support for tracing block IO actions"
 348         depends on SYSFS
 349         depends on BLOCK
 350         select RELAY
 351         select DEBUG_FS
 352         select TRACEPOINTS
 353         select GENERIC_TRACER
 354         select STACKTRACE
 355         help
 356           Say Y here if you want to be able to trace the block layer actions
 357           on a given queue. Tracing allows you to see any traffic happening
 358           on a block device queue. For more information (and the userspace
 359           support tools needed), fetch the blktrace tools from:
 360
 361           git://git.kernel.dk/blktrace.git
 362
 363           Tracing also is possible using the ftrace interface, e.g.:
 364
 365             echo 1 > /sys/block/sda/sda1/trace/enable
 366             echo blk > /sys/kernel/debug/tracing/current_tracer
 367             cat /sys/kernel/debug/tracing/trace_pipe
 368
 369           If unsure, say N.
 370
 371 config KPROBE_EVENT
 372         depends on KPROBES
 373         depends on HAVE_REGS_AND_STACK_ACCESS_API
 374         bool "Enable kprobes-based dynamic events"
 375         select TRACING
 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 DYNAMIC_FTRACE
 389         bool "enable/disable ftrace tracepoints dynamically"
 390         depends on FUNCTION_TRACER
 391         depends on HAVE_DYNAMIC_FTRACE
 392         default y
 393         help
 394           This option will modify all the calls to ftrace dynamically
 395           (will patch them out of the binary image and replace them
 396           with a No-Op instruction) as they are called. A table is
 397           created to dynamically enable them again.
 398
 399           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 400           otherwise has native performance as long as no tracing is active.
 401
 402           The changes to the code are done by a kernel thread that
 403           wakes up once a second and checks to see if any ftrace calls
 404           were made. If so, it runs stop_machine (stops all CPUS)
 405           and modifies the code to jump over the call to ftrace.
 406
 407 config FUNCTION_PROFILER
 408         bool "Kernel function profiler"
 409         depends on FUNCTION_TRACER
 410         default n
 411         help
 412           This option enables the kernel function profiler. A file is created
 413           in debugfs called function_profile_enabled which defaults to zero.
 414           When a 1 is echoed into this file profiling begins, and when a
 415           zero is entered, profiling stops. A "functions" file is created in
 416           the trace_stats directory; this file shows the list of functions that
 417           have been hit and their counters.
 418
 419           If in doubt, say N.
 420
 421 config FTRACE_MCOUNT_RECORD
 422         def_bool y
 423         depends on DYNAMIC_FTRACE
 424         depends on HAVE_FTRACE_MCOUNT_RECORD
 425
 426 config FTRACE_SELFTEST
 427         bool
 428
 429 config FTRACE_STARTUP_TEST
 430         bool "Perform a startup test on ftrace"
 431         depends on GENERIC_TRACER
 432         select FTRACE_SELFTEST
 433         help
 434           This option performs a series of startup tests on ftrace. On bootup
 435           a series of tests are made to verify that the tracer is
 436           functioning properly. It will do tests on all the configured
 437           tracers of ftrace.
 438
 439 config EVENT_TRACE_TEST_SYSCALLS
 440         bool "Run selftest on syscall events"
 441         depends on FTRACE_STARTUP_TEST
 442         help
 443          This option will also enable testing every syscall event.
 444          It only enables the event and disables it and runs various loads
 445          with the event enabled. This adds a bit more time for kernel boot
 446          up since it runs this on every system call defined.
 447
 448          TBD - enable a way to actually call the syscalls as we test their
 449                events
 450
 451 config MMIOTRACE
 452         bool "Memory mapped IO tracing"
 453         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 454         select GENERIC_TRACER
 455         help
 456           Mmiotrace traces Memory Mapped I/O access and is meant for
 457           debugging and reverse engineering. It is called from the ioremap
 458           implementation and works via page faults. Tracing is disabled by
 459           default and can be enabled at run-time.
 460
 461           See Documentation/trace/mmiotrace.txt.
 462           If you are not helping to develop drivers, say N.
 463
 464 config MMIOTRACE_TEST
 465         tristate "Test module for mmiotrace"
 466         depends on MMIOTRACE && m
 467         help
 468           This is a dumb module for testing mmiotrace. It is very dangerous
 469           as it will write garbage to IO memory starting at a given address.
 470           However, it should be safe to use on e.g. unused portion of VRAM.
 471
 472           Say N, unless you absolutely know what you are doing.
 473
 474 config RING_BUFFER_BENCHMARK
 475         tristate "Ring buffer benchmark stress tester"
 476         depends on RING_BUFFER
 477         help
 478           This option creates a test to stress the ring buffer and benchmark it.
 479           It creates its own ring buffer such that it will not interfere with
 480           any other users of the ring buffer (such as ftrace). It then creates
 481           a producer and consumer that will run for 10 seconds and sleep for
 482           10 seconds. Each interval it will print out the number of events
 483           it recorded and give a rough estimate of how long each iteration took.
 484
 485           It does not disable interrupts or raise its priority, so it may be
 486           affected by processes that are running.
 487
 488           If unsure, say N.
 489
 490 endif # FTRACE
 491
 492 endif # TRACING_SUPPORT
 493