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
  15 config HAVE_FUNCTION_TRACER
  16         bool
  17
  18 config HAVE_FUNCTION_GRAPH_TRACER
  19         bool
  20
  21 config HAVE_FUNCTION_TRACE_MCOUNT_TEST
  22         bool
  23         help
  24          This gets selected when the arch tests the function_trace_stop
  25          variable at the mcount call site. Otherwise, this variable
  26          is tested by the called function.
  27
  28 config HAVE_DYNAMIC_FTRACE
  29         bool
  30
  31 config HAVE_FTRACE_MCOUNT_RECORD
  32         bool
  33
  34 config HAVE_HW_BRANCH_TRACER
  35         bool
  36
  37 config HAVE_FTRACE_SYSCALLS
  38         bool
  39
  40 config TRACER_MAX_TRACE
  41         bool
  42
  43 config RING_BUFFER
  44         bool
  45
  46 config FTRACE_NMI_ENTER
  47        bool
  48        depends on HAVE_FTRACE_NMI_ENTER
  49        default y
  50
  51 config EVENT_TRACING
  52         bool
  53
  54 config TRACING
  55         bool
  56         select DEBUG_FS
  57         select RING_BUFFER
  58         select STACKTRACE if STACKTRACE_SUPPORT
  59         select TRACEPOINTS
  60         select NOP_TRACER
  61         select BINARY_PRINTF
  62         select EVENT_TRACING
  63
  64 #
  65 # Minimum requirements an architecture has to meet for us to
  66 # be able to offer generic tracing facilities:
  67 #
  68 config TRACING_SUPPORT
  69         bool
  70         # PPC32 has no irqflags tracing support, but it can use most of the
  71         # tracers anyway, they were tested to build and work. Note that new
  72         # exceptions to this list aren't welcomed, better implement the
  73         # irqflags tracing for your architecture.
  74         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
  75         depends on STACKTRACE_SUPPORT
  76         default y
  77
  78 if TRACING_SUPPORT
  79
  80 menuconfig FTRACE
  81         bool "Tracers"
  82         help
  83          Enable the kernel tracing infrastructure.
  84
  85 if FTRACE
  86
  87 config FUNCTION_TRACER
  88         bool "Kernel Function Tracer"
  89         depends on HAVE_FUNCTION_TRACER
  90         select FRAME_POINTER
  91         select KALLSYMS
  92         select TRACING
  93         select CONTEXT_SWITCH_TRACER
  94         help
  95           Enable the kernel to trace every kernel function. This is done
  96           by using a compiler feature to insert a small, 5-byte No-Operation
  97           instruction to the beginning of every kernel function, which NOP
  98           sequence is then dynamically patched into a tracer call when
  99           tracing is enabled by the administrator. If it's runtime disabled
 100           (the bootup default), then the overhead of the instructions is very
 101           small and not measurable even in micro-benchmarks.
 102
 103 config FUNCTION_GRAPH_TRACER
 104         bool "Kernel Function Graph Tracer"
 105         depends on HAVE_FUNCTION_GRAPH_TRACER
 106         depends on FUNCTION_TRACER
 107         default y
 108         help
 109           Enable the kernel to trace a function at both its return
 110           and its entry.
 111           Its first purpose is to trace the duration of functions and
 112           draw a call graph for each thread with some information like
 113           the return value. This is done by setting the current return
 114           address on the current task structure into a stack of calls.
 115
 116
 117 config IRQSOFF_TRACER
 118         bool "Interrupts-off Latency Tracer"
 119         default n
 120         depends on TRACE_IRQFLAGS_SUPPORT
 121         depends on GENERIC_TIME
 122         select TRACE_IRQFLAGS
 123         select TRACING
 124         select TRACER_MAX_TRACE
 125         help
 126           This option measures the time spent in irqs-off critical
 127           sections, with microsecond accuracy.
 128
 129           The default measurement method is a maximum search, which is
 130           disabled by default and can be runtime (re-)started
 131           via:
 132
 133               echo 0 > /debugfs/tracing/tracing_max_latency
 134
 135           (Note that kernel size and overhead increases with this option
 136           enabled. This option and the preempt-off timing option can be
 137           used together or separately.)
 138
 139 config PREEMPT_TRACER
 140         bool "Preemption-off Latency Tracer"
 141         default n
 142         depends on GENERIC_TIME
 143         depends on PREEMPT
 144         select TRACING
 145         select TRACER_MAX_TRACE
 146         help
 147           This option measures the time spent in preemption off critical
 148           sections, with microsecond accuracy.
 149
 150           The default measurement method is a maximum search, which is
 151           disabled by default and can be runtime (re-)started
 152           via:
 153
 154               echo 0 > /debugfs/tracing/tracing_max_latency
 155
 156           (Note that kernel size and overhead increases with this option
 157           enabled. This option and the irqs-off timing option can be
 158           used together or separately.)
 159
 160 config SYSPROF_TRACER
 161         bool "Sysprof Tracer"
 162         depends on X86
 163         select TRACING
 164         select CONTEXT_SWITCH_TRACER
 165         help
 166           This tracer provides the trace needed by the 'Sysprof' userspace
 167           tool.
 168
 169 config SCHED_TRACER
 170         bool "Scheduling Latency Tracer"
 171         select TRACING
 172         select CONTEXT_SWITCH_TRACER
 173         select TRACER_MAX_TRACE
 174         help
 175           This tracer tracks the latency of the highest priority task
 176           to be scheduled in, starting from the point it has woken up.
 177
 178 config CONTEXT_SWITCH_TRACER
 179         bool "Trace process context switches"
 180         select TRACING
 181         select MARKERS
 182         help
 183           This tracer gets called from the context switch and records
 184           all switching of tasks.
 185
 186 config ENABLE_EVENT_TRACING
 187         bool "Trace various events in the kernel"
 188         select TRACING
 189         help
 190           This tracer hooks to various trace points in the kernel
 191           allowing the user to pick and choose which trace point they
 192           want to trace.
 193
 194           Note, all tracers enable event tracing. This option is
 195           only a convenience to enable event tracing when no other
 196           tracers are selected.
 197
 198 config FTRACE_SYSCALLS
 199         bool "Trace syscalls"
 200         depends on HAVE_FTRACE_SYSCALLS
 201         select TRACING
 202         select KALLSYMS
 203         help
 204           Basic tracer to catch the syscall entry and exit events.
 205
 206 config BOOT_TRACER
 207         bool "Trace boot initcalls"
 208         select TRACING
 209         select CONTEXT_SWITCH_TRACER
 210         help
 211           This tracer helps developers to optimize boot times: it records
 212           the timings of the initcalls and traces key events and the identity
 213           of tasks that can cause boot delays, such as context-switches.
 214
 215           Its aim is to be parsed by the /scripts/bootgraph.pl tool to
 216           produce pretty graphics about boot inefficiencies, giving a visual
 217           representation of the delays during initcalls - but the raw
 218           /debug/tracing/trace text output is readable too.
 219
 220           You must pass in ftrace=initcall to the kernel command line
 221           to enable this on bootup.
 222
 223 config TRACE_BRANCH_PROFILING
 224         bool
 225         select TRACING
 226
 227 choice
 228         prompt "Branch Profiling"
 229         default BRANCH_PROFILE_NONE
 230         help
 231          The branch profiling is a software profiler. It will add hooks
 232          into the C conditionals to test which path a branch takes.
 233
 234          The likely/unlikely profiler only looks at the conditions that
 235          are annotated with a likely or unlikely macro.
 236
 237          The "all branch" profiler will profile every if statement in the
 238          kernel. This profiler will also enable the likely/unlikely
 239          profiler as well.
 240
 241          Either of the above profilers add a bit of overhead to the system.
 242          If unsure choose "No branch profiling".
 243
 244 config BRANCH_PROFILE_NONE
 245         bool "No branch profiling"
 246         help
 247          No branch profiling. Branch profiling adds a bit of overhead.
 248          Only enable it if you want to analyse the branching behavior.
 249          Otherwise keep it disabled.
 250
 251 config PROFILE_ANNOTATED_BRANCHES
 252         bool "Trace likely/unlikely profiler"
 253         select TRACE_BRANCH_PROFILING
 254         help
 255           This tracer profiles all the the likely and unlikely macros
 256           in the kernel. It will display the results in:
 257
 258           /debugfs/tracing/profile_annotated_branch
 259
 260           Note: this will add a significant overhead, only turn this
 261           on if you need to profile the system's use of these macros.
 262
 263 config PROFILE_ALL_BRANCHES
 264         bool "Profile all if conditionals"
 265         select TRACE_BRANCH_PROFILING
 266         help
 267           This tracer profiles all branch conditions. Every if ()
 268           taken in the kernel is recorded whether it hit or miss.
 269           The results will be displayed in:
 270
 271           /debugfs/tracing/profile_branch
 272
 273           This option also enables the likely/unlikely profiler.
 274
 275           This configuration, when enabled, will impose a great overhead
 276           on the system. This should only be enabled when the system
 277           is to be analyzed
 278 endchoice
 279
 280 config TRACING_BRANCHES
 281         bool
 282         help
 283           Selected by tracers that will trace the likely and unlikely
 284           conditions. This prevents the tracers themselves from being
 285           profiled. Profiling the tracing infrastructure can only happen
 286           when the likelys and unlikelys are not being traced.
 287
 288 config BRANCH_TRACER
 289         bool "Trace likely/unlikely instances"
 290         depends on TRACE_BRANCH_PROFILING
 291         select TRACING_BRANCHES
 292         help
 293           This traces the events of likely and unlikely condition
 294           calls in the kernel.  The difference between this and the
 295           "Trace likely/unlikely profiler" is that this is not a
 296           histogram of the callers, but actually places the calling
 297           events into a running trace buffer to see when and where the
 298           events happened, as well as their results.
 299
 300           Say N if unsure.
 301
 302 config POWER_TRACER
 303         bool "Trace power consumption behavior"
 304         depends on X86
 305         select TRACING
 306         help
 307           This tracer helps developers to analyze and optimize the kernels
 308           power management decisions, specifically the C-state and P-state
 309           behavior.
 310
 311
 312 config STACK_TRACER
 313         bool "Trace max stack"
 314         depends on HAVE_FUNCTION_TRACER
 315         select FUNCTION_TRACER
 316         select STACKTRACE
 317         select KALLSYMS
 318         help
 319           This special tracer records the maximum stack footprint of the
 320           kernel and displays it in debugfs/tracing/stack_trace.
 321
 322           This tracer works by hooking into every function call that the
 323           kernel executes, and keeping a maximum stack depth value and
 324           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 325           then it will not have any overhead while the stack tracer
 326           is disabled.
 327
 328           To enable the stack tracer on bootup, pass in 'stacktrace'
 329           on the kernel command line.
 330
 331           The stack tracer can also be enabled or disabled via the
 332           sysctl kernel.stack_tracer_enabled
 333
 334           Say N if unsure.
 335
 336 config HW_BRANCH_TRACER
 337         depends on HAVE_HW_BRANCH_TRACER
 338         bool "Trace hw branches"
 339         select TRACING
 340         help
 341           This tracer records all branches on the system in a circular
 342           buffer giving access to the last N branches for each cpu.
 343
 344 config KMEMTRACE
 345         bool "Trace SLAB allocations"
 346         select TRACING
 347         help
 348           kmemtrace provides tracing for slab allocator functions, such as
 349           kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
 350           data is then fed to the userspace application in order to analyse
 351           allocation hotspots, internal fragmentation and so on, making it
 352           possible to see how well an allocator performs, as well as debug
 353           and profile kernel code.
 354
 355           This requires an userspace application to use. See
 356           Documentation/trace/kmemtrace.txt for more information.
 357
 358           Saying Y will make the kernel somewhat larger and slower. However,
 359           if you disable kmemtrace at run-time or boot-time, the performance
 360           impact is minimal (depending on the arch the kernel is built for).
 361
 362           If unsure, say N.
 363
 364 config WORKQUEUE_TRACER
 365         bool "Trace workqueues"
 366         select TRACING
 367         help
 368           The workqueue tracer provides some statistical informations
 369           about each cpu workqueue thread such as the number of the
 370           works inserted and executed since their creation. It can help
 371           to evaluate the amount of work each of them have to perform.
 372           For example it can help a developer to decide whether he should
 373           choose a per cpu workqueue instead of a singlethreaded one.
 374
 375 config BLK_DEV_IO_TRACE
 376         bool "Support for tracing block io actions"
 377         depends on SYSFS
 378         depends on BLOCK
 379         select RELAY
 380         select DEBUG_FS
 381         select TRACEPOINTS
 382         select TRACING
 383         select STACKTRACE
 384         help
 385           Say Y here if you want to be able to trace the block layer actions
 386           on a given queue. Tracing allows you to see any traffic happening
 387           on a block device queue. For more information (and the userspace
 388           support tools needed), fetch the blktrace tools from:
 389
 390           git://git.kernel.dk/blktrace.git
 391
 392           Tracing also is possible using the ftrace interface, e.g.:
 393
 394             echo 1 > /sys/block/sda/sda1/trace/enable
 395             echo blk > /sys/kernel/debug/tracing/current_tracer
 396             cat /sys/kernel/debug/tracing/trace_pipe
 397
 398           If unsure, say N.
 399
 400 config DYNAMIC_FTRACE
 401         bool "enable/disable ftrace tracepoints dynamically"
 402         depends on FUNCTION_TRACER
 403         depends on HAVE_DYNAMIC_FTRACE
 404         default y
 405         help
 406          This option will modify all the calls to ftrace dynamically
 407          (will patch them out of the binary image and replaces them
 408          with a No-Op instruction) as they are called. A table is
 409          created to dynamically enable them again.
 410
 411          This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
 412          has native performance as long as no tracing is active.
 413
 414          The changes to the code are done by a kernel thread that
 415          wakes up once a second and checks to see if any ftrace calls
 416          were made. If so, it runs stop_machine (stops all CPUS)
 417          and modifies the code to jump over the call to ftrace.
 418
 419 config FUNCTION_PROFILER
 420         bool "Kernel function profiler"
 421         depends on FUNCTION_TRACER
 422         default n
 423         help
 424          This option enables the kernel function profiler. A file is created
 425          in debugfs called function_profile_enabled which defaults to zero.
 426          When a 1 is echoed into this file profiling begins, and when a
 427          zero is entered, profiling stops. A file in the trace_stats
 428          directory called functions, that show the list of functions that
 429          have been hit and their counters.
 430
 431          If in doubt, say N
 432
 433 config FTRACE_MCOUNT_RECORD
 434         def_bool y
 435         depends on DYNAMIC_FTRACE
 436         depends on HAVE_FTRACE_MCOUNT_RECORD
 437
 438 config FTRACE_SELFTEST
 439         bool
 440
 441 config FTRACE_STARTUP_TEST
 442         bool "Perform a startup test on ftrace"
 443         depends on TRACING
 444         select FTRACE_SELFTEST
 445         help
 446           This option performs a series of startup tests on ftrace. On bootup
 447           a series of tests are made to verify that the tracer is
 448           functioning properly. It will do tests on all the configured
 449           tracers of ftrace.
 450
 451 config MMIOTRACE
 452         bool "Memory mapped IO tracing"
 453         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 454         select TRACING
 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 endif # FTRACE
 475
 476 endif # TRACING_SUPPORT
 477