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 TRACE_CLOCK
  66         bool
  67
  68 config RING_BUFFER
  69         bool
  70         select TRACE_CLOCK
  71
  72 config FTRACE_NMI_ENTER
  73        bool
  74        depends on HAVE_FTRACE_NMI_ENTER
  75        default y
  76
  77 config EVENT_TRACING
  78         select CONTEXT_SWITCH_TRACER
  79         bool
  80
  81 config EVENT_POWER_TRACING_DEPRECATED
  82         depends on EVENT_TRACING
  83         bool "Deprecated power event trace API, to be removed"
  84         default y
  85         help
  86           Provides old power event types:
  87           C-state/idle accounting events:
  88           power:power_start
  89           power:power_end
  90           and old cpufreq accounting event:
  91           power:power_frequency
  92           This is for userspace compatibility
  93           and will vanish after 5 kernel iterations,
  94           namely 3.1.
  95
  96 config CONTEXT_SWITCH_TRACER
  97         bool
  98
  99 config RING_BUFFER_ALLOW_SWAP
 100         bool
 101         help
 102          Allow the use of ring_buffer_swap_cpu.
 103          Adds a very slight overhead to tracing when enabled.
 104
 105 # All tracer options should select GENERIC_TRACER. For those options that are
 106 # enabled by all tracers (context switch and event tracer) they select TRACING.
 107 # This allows those options to appear when no other tracer is selected. But the
 108 # options do not appear when something else selects it. We need the two options
 109 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
 110 # hiding of the automatic options.
 111
 112 config TRACING
 113         bool
 114         select DEBUG_FS
 115         select RING_BUFFER
 116         select STACKTRACE if STACKTRACE_SUPPORT
 117         select TRACEPOINTS
 118         select NOP_TRACER
 119         select BINARY_PRINTF
 120         select EVENT_TRACING
 121         select TRACE_CLOCK
 122         select IRQ_WORK
 123
 124 config GENERIC_TRACER
 125         bool
 126         select TRACING
 127
 128 #
 129 # Minimum requirements an architecture has to meet for us to
 130 # be able to offer generic tracing facilities:
 131 #
 132 config TRACING_SUPPORT
 133         bool
 134         # PPC32 has no irqflags tracing support, but it can use most of the
 135         # tracers anyway, they were tested to build and work. Note that new
 136         # exceptions to this list aren't welcomed, better implement the
 137         # irqflags tracing for your architecture.
 138         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
 139         depends on STACKTRACE_SUPPORT
 140         default y
 141
 142 if TRACING_SUPPORT
 143
 144 menuconfig FTRACE
 145         bool "Tracers"
 146         default y if DEBUG_KERNEL
 147         help
 148           Enable the kernel tracing infrastructure.
 149
 150 if FTRACE
 151
 152 config FUNCTION_TRACER
 153         bool "Kernel Function Tracer"
 154         depends on HAVE_FUNCTION_TRACER
 155         select KALLSYMS
 156         select GENERIC_TRACER
 157         select CONTEXT_SWITCH_TRACER
 158         help
 159           Enable the kernel to trace every kernel function. This is done
 160           by using a compiler feature to insert a small, 5-byte No-Operation
 161           instruction at the beginning of every kernel function, which NOP
 162           sequence is then dynamically patched into a tracer call when
 163           tracing is enabled by the administrator. If it's runtime disabled
 164           (the bootup default), then the overhead of the instructions is very
 165           small and not measurable even in micro-benchmarks.
 166
 167 config FUNCTION_GRAPH_TRACER
 168         bool "Kernel Function Graph Tracer"
 169         depends on HAVE_FUNCTION_GRAPH_TRACER
 170         depends on FUNCTION_TRACER
 171         depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 172         default y
 173         help
 174           Enable the kernel to trace a function at both its return
 175           and its entry.
 176           Its first purpose is to trace the duration of functions and
 177           draw a call graph for each thread with some information like
 178           the return value. This is done by setting the current return
 179           address on the current task structure into a stack of calls.
 180
 181
 182 config IRQSOFF_TRACER
 183         bool "Interrupts-off Latency Tracer"
 184         default n
 185         depends on TRACE_IRQFLAGS_SUPPORT
 186         depends on !ARCH_USES_GETTIMEOFFSET
 187         select TRACE_IRQFLAGS
 188         select GENERIC_TRACER
 189         select TRACER_MAX_TRACE
 190         select RING_BUFFER_ALLOW_SWAP
 191         help
 192           This option measures the time spent in irqs-off critical
 193           sections, with microsecond accuracy.
 194
 195           The default measurement method is a maximum search, which is
 196           disabled by default and can be runtime (re-)started
 197           via:
 198
 199               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 200
 201           (Note that kernel size and overhead increase with this option
 202           enabled. This option and the preempt-off timing option can be
 203           used together or separately.)
 204
 205 config PREEMPT_TRACER
 206         bool "Preemption-off Latency Tracer"
 207         default n
 208         depends on !ARCH_USES_GETTIMEOFFSET
 209         depends on PREEMPT
 210         select GENERIC_TRACER
 211         select TRACER_MAX_TRACE
 212         select RING_BUFFER_ALLOW_SWAP
 213         help
 214           This option measures the time spent in preemption-off critical
 215           sections, with microsecond accuracy.
 216
 217           The default measurement method is a maximum search, which is
 218           disabled by default and can be runtime (re-)started
 219           via:
 220
 221               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 222
 223           (Note that kernel size and overhead increase with this option
 224           enabled. This option and the irqs-off timing option can be
 225           used together or separately.)
 226
 227 config SCHED_TRACER
 228         bool "Scheduling Latency Tracer"
 229         select GENERIC_TRACER
 230         select CONTEXT_SWITCH_TRACER
 231         select TRACER_MAX_TRACE
 232         help
 233           This tracer tracks the latency of the highest priority task
 234           to be scheduled in, starting from the point it has woken up.
 235
 236 config ENABLE_DEFAULT_TRACERS
 237         bool "Trace process context switches and events"
 238         depends on !GENERIC_TRACER
 239         select TRACING
 240         help
 241           This tracer hooks to various trace points in the kernel,
 242           allowing the user to pick and choose which trace point they
 243           want to trace. It also includes the sched_switch tracer plugin.
 244
 245 config FTRACE_SYSCALLS
 246         bool "Trace syscalls"
 247         depends on HAVE_SYSCALL_TRACEPOINTS
 248         select GENERIC_TRACER
 249         select KALLSYMS
 250         help
 251           Basic tracer to catch the syscall entry and exit events.
 252
 253 config TRACE_BRANCH_PROFILING
 254         bool
 255         select GENERIC_TRACER
 256
 257 choice
 258         prompt "Branch Profiling"
 259         default BRANCH_PROFILE_NONE
 260         help
 261          The branch profiling is a software profiler. It will add hooks
 262          into the C conditionals to test which path a branch takes.
 263
 264          The likely/unlikely profiler only looks at the conditions that
 265          are annotated with a likely or unlikely macro.
 266
 267          The "all branch" profiler will profile every if-statement in the
 268          kernel. This profiler will also enable the likely/unlikely
 269          profiler.
 270
 271          Either of the above profilers adds a bit of overhead to the system.
 272          If unsure, choose "No branch profiling".
 273
 274 config BRANCH_PROFILE_NONE
 275         bool "No branch profiling"
 276         help
 277           No branch profiling. Branch profiling adds a bit of overhead.
 278           Only enable it if you want to analyse the branching behavior.
 279           Otherwise keep it disabled.
 280
 281 config PROFILE_ANNOTATED_BRANCHES
 282         bool "Trace likely/unlikely profiler"
 283         select TRACE_BRANCH_PROFILING
 284         help
 285           This tracer profiles all likely and unlikely macros
 286           in the kernel. It will display the results in:
 287
 288           /sys/kernel/debug/tracing/trace_stat/branch_annotated
 289
 290           Note: this will add a significant overhead; only turn this
 291           on if you need to profile the system's use of these macros.
 292
 293 config PROFILE_ALL_BRANCHES
 294         bool "Profile all if conditionals"
 295         select TRACE_BRANCH_PROFILING
 296         help
 297           This tracer profiles all branch conditions. Every if ()
 298           taken in the kernel is recorded whether it hit or miss.
 299           The results will be displayed in:
 300
 301           /sys/kernel/debug/tracing/trace_stat/branch_all
 302
 303           This option also enables the likely/unlikely profiler.
 304
 305           This configuration, when enabled, will impose a great overhead
 306           on the system. This should only be enabled when the system
 307           is to be analyzed in much detail.
 308 endchoice
 309
 310 config TRACING_BRANCHES
 311         bool
 312         help
 313           Selected by tracers that will trace the likely and unlikely
 314           conditions. This prevents the tracers themselves from being
 315           profiled. Profiling the tracing infrastructure can only happen
 316           when the likelys and unlikelys are not being traced.
 317
 318 config BRANCH_TRACER
 319         bool "Trace likely/unlikely instances"
 320         depends on TRACE_BRANCH_PROFILING
 321         select TRACING_BRANCHES
 322         help
 323           This traces the events of likely and unlikely condition
 324           calls in the kernel.  The difference between this and the
 325           "Trace likely/unlikely profiler" is that this is not a
 326           histogram of the callers, but actually places the calling
 327           events into a running trace buffer to see when and where the
 328           events happened, as well as their results.
 329
 330           Say N if unsure.
 331
 332 config STACK_TRACER
 333         bool "Trace max stack"
 334         depends on HAVE_FUNCTION_TRACER
 335         select FUNCTION_TRACER
 336         select STACKTRACE
 337         select KALLSYMS
 338         help
 339           This special tracer records the maximum stack footprint of the
 340           kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 341
 342           This tracer works by hooking into every function call that the
 343           kernel executes, and keeping a maximum stack depth value and
 344           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 345           then it will not have any overhead while the stack tracer
 346           is disabled.
 347
 348           To enable the stack tracer on bootup, pass in 'stacktrace'
 349           on the kernel command line.
 350
 351           The stack tracer can also be enabled or disabled via the
 352           sysctl kernel.stack_tracer_enabled
 353
 354           Say N if unsure.
 355
 356 config BLK_DEV_IO_TRACE
 357         bool "Support for tracing block IO actions"
 358         depends on SYSFS
 359         depends on BLOCK
 360         select RELAY
 361         select DEBUG_FS
 362         select TRACEPOINTS
 363         select GENERIC_TRACER
 364         select STACKTRACE
 365         help
 366           Say Y here if you want to be able to trace the block layer actions
 367           on a given queue. Tracing allows you to see any traffic happening
 368           on a block device queue. For more information (and the userspace
 369           support tools needed), fetch the blktrace tools from:
 370
 371           git://git.kernel.dk/blktrace.git
 372
 373           Tracing also is possible using the ftrace interface, e.g.:
 374
 375             echo 1 > /sys/block/sda/sda1/trace/enable
 376             echo blk > /sys/kernel/debug/tracing/current_tracer
 377             cat /sys/kernel/debug/tracing/trace_pipe
 378
 379           If unsure, say N.
 380
 381 config KPROBE_EVENT
 382         depends on KPROBES
 383         depends on HAVE_REGS_AND_STACK_ACCESS_API
 384         bool "Enable kprobes-based dynamic events"
 385         select TRACING
 386         select PROBE_EVENTS
 387         default y
 388         help
 389           This allows the user to add tracing events (similar to tracepoints)
 390           on the fly via the ftrace interface. See
 391           Documentation/trace/kprobetrace.txt for more details.
 392
 393           Those events can be inserted wherever kprobes can probe, and record
 394           various register and memory values.
 395
 396           This option is also required by perf-probe subcommand of perf tools.
 397           If you want to use perf tools, this option is strongly recommended.
 398
 399 config UPROBE_EVENT
 400         bool "Enable uprobes-based dynamic events"
 401         depends on ARCH_SUPPORTS_UPROBES
 402         depends on MMU
 403         select UPROBES
 404         select PROBE_EVENTS
 405         select TRACING
 406         default n
 407         help
 408           This allows the user to add tracing events on top of userspace
 409           dynamic events (similar to tracepoints) on the fly via the trace
 410           events interface. Those events can be inserted wherever uprobes
 411           can probe, and record various registers.
 412           This option is required if you plan to use perf-probe subcommand
 413           of perf tools on user space applications.
 414
 415 config PROBE_EVENTS
 416         def_bool n
 417
 418 config DYNAMIC_FTRACE
 419         bool "enable/disable ftrace tracepoints dynamically"
 420         depends on FUNCTION_TRACER
 421         depends on HAVE_DYNAMIC_FTRACE
 422         default y
 423         help
 424           This option will modify all the calls to ftrace dynamically
 425           (will patch them out of the binary image and replace them
 426           with a No-Op instruction) as they are called. A table is
 427           created to dynamically enable them again.
 428
 429           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 430           otherwise has native performance as long as no tracing is active.
 431
 432           The changes to the code are done by a kernel thread that
 433           wakes up once a second and checks to see if any ftrace calls
 434           were made. If so, it runs stop_machine (stops all CPUS)
 435           and modifies the code to jump over the call to ftrace.
 436
 437 config FUNCTION_PROFILER
 438         bool "Kernel function profiler"
 439         depends on FUNCTION_TRACER
 440         default n
 441         help
 442           This option enables the kernel function profiler. A file is created
 443           in debugfs called function_profile_enabled which defaults to zero.
 444           When a 1 is echoed into this file profiling begins, and when a
 445           zero is entered, profiling stops. A "functions" file is created in
 446           the trace_stats directory; this file shows the list of functions that
 447           have been hit and their counters.
 448
 449           If in doubt, say N.
 450
 451 config FTRACE_MCOUNT_RECORD
 452         def_bool y
 453         depends on DYNAMIC_FTRACE
 454         depends on HAVE_FTRACE_MCOUNT_RECORD
 455
 456 config FTRACE_SELFTEST
 457         bool
 458
 459 config FTRACE_STARTUP_TEST
 460         bool "Perform a startup test on ftrace"
 461         depends on GENERIC_TRACER
 462         select FTRACE_SELFTEST
 463         help
 464           This option performs a series of startup tests on ftrace. On bootup
 465           a series of tests are made to verify that the tracer is
 466           functioning properly. It will do tests on all the configured
 467           tracers of ftrace.
 468
 469 config EVENT_TRACE_TEST_SYSCALLS
 470         bool "Run selftest on syscall events"
 471         depends on FTRACE_STARTUP_TEST
 472         help
 473          This option will also enable testing every syscall event.
 474          It only enables the event and disables it and runs various loads
 475          with the event enabled. This adds a bit more time for kernel boot
 476          up since it runs this on every system call defined.
 477
 478          TBD - enable a way to actually call the syscalls as we test their
 479                events
 480
 481 config MMIOTRACE
 482         bool "Memory mapped IO tracing"
 483         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 484         select GENERIC_TRACER
 485         help
 486           Mmiotrace traces Memory Mapped I/O access and is meant for
 487           debugging and reverse engineering. It is called from the ioremap
 488           implementation and works via page faults. Tracing is disabled by
 489           default and can be enabled at run-time.
 490
 491           See Documentation/trace/mmiotrace.txt.
 492           If you are not helping to develop drivers, say N.
 493
 494 config MMIOTRACE_TEST
 495         tristate "Test module for mmiotrace"
 496         depends on MMIOTRACE && m
 497         help
 498           This is a dumb module for testing mmiotrace. It is very dangerous
 499           as it will write garbage to IO memory starting at a given address.
 500           However, it should be safe to use on e.g. unused portion of VRAM.
 501
 502           Say N, unless you absolutely know what you are doing.
 503
 504 config RING_BUFFER_BENCHMARK
 505         tristate "Ring buffer benchmark stress tester"
 506         depends on RING_BUFFER
 507         help
 508           This option creates a test to stress the ring buffer and benchmark it.
 509           It creates its own ring buffer such that it will not interfere with
 510           any other users of the ring buffer (such as ftrace). It then creates
 511           a producer and consumer that will run for 10 seconds and sleep for
 512           10 seconds. Each interval it will print out the number of events
 513           it recorded and give a rough estimate of how long each iteration took.
 514
 515           It does not disable interrupts or raise its priority, so it may be
 516           affected by processes that are running.
 517
 518           If unsure, say N.
 519
 520 endif # FTRACE
 521
 522 endif # TRACING_SUPPORT
 523