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         select CONTEXT_SWITCH_TRACER
  53         bool
  54
  55 config CONTEXT_SWITCH_TRACER
  56         select MARKERS
  57         bool
  58
  59 # All tracer options should select GENERIC_TRACER. For those options that are
  60 # enabled by all tracers (context switch and event tracer) they select TRACING.
  61 # This allows those options to appear when no other tracer is selected. But the
  62 # options do not appear when something else selects it. We need the two options
  63 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
  64 # hidding of the automatic options options.
  65
  66 config TRACING
  67         bool
  68         select DEBUG_FS
  69         select RING_BUFFER
  70         select STACKTRACE if STACKTRACE_SUPPORT
  71         select TRACEPOINTS
  72         select NOP_TRACER
  73         select BINARY_PRINTF
  74         select EVENT_TRACING
  75
  76 config GENERIC_TRACER
  77         bool
  78         select TRACING
  79
  80 #
  81 # Minimum requirements an architecture has to meet for us to
  82 # be able to offer generic tracing facilities:
  83 #
  84 config TRACING_SUPPORT
  85         bool
  86         # PPC32 has no irqflags tracing support, but it can use most of the
  87         # tracers anyway, they were tested to build and work. Note that new
  88         # exceptions to this list aren't welcomed, better implement the
  89         # irqflags tracing for your architecture.
  90         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
  91         depends on STACKTRACE_SUPPORT
  92         default y
  93
  94 if TRACING_SUPPORT
  95
  96 menuconfig FTRACE
  97         bool "Tracers"
  98         default y if DEBUG_KERNEL
  99         help
 100          Enable the kernel tracing infrastructure.
 101
 102 if FTRACE
 103
 104 config FUNCTION_TRACER
 105         bool "Kernel Function Tracer"
 106         depends on HAVE_FUNCTION_TRACER
 107         select FRAME_POINTER
 108         select KALLSYMS
 109         select GENERIC_TRACER
 110         select CONTEXT_SWITCH_TRACER
 111         help
 112           Enable the kernel to trace every kernel function. This is done
 113           by using a compiler feature to insert a small, 5-byte No-Operation
 114           instruction to the beginning of every kernel function, which NOP
 115           sequence is then dynamically patched into a tracer call when
 116           tracing is enabled by the administrator. If it's runtime disabled
 117           (the bootup default), then the overhead of the instructions is very
 118           small and not measurable even in micro-benchmarks.
 119
 120 config FUNCTION_GRAPH_TRACER
 121         bool "Kernel Function Graph Tracer"
 122         depends on HAVE_FUNCTION_GRAPH_TRACER
 123         depends on FUNCTION_TRACER
 124         default y
 125         help
 126           Enable the kernel to trace a function at both its return
 127           and its entry.
 128           Its first purpose is to trace the duration of functions and
 129           draw a call graph for each thread with some information like
 130           the return value. This is done by setting the current return
 131           address on the current task structure into a stack of calls.
 132
 133
 134 config IRQSOFF_TRACER
 135         bool "Interrupts-off Latency Tracer"
 136         default n
 137         depends on TRACE_IRQFLAGS_SUPPORT
 138         depends on GENERIC_TIME
 139         select TRACE_IRQFLAGS
 140         select GENERIC_TRACER
 141         select TRACER_MAX_TRACE
 142         help
 143           This option measures the time spent in irqs-off critical
 144           sections, with microsecond accuracy.
 145
 146           The default measurement method is a maximum search, which is
 147           disabled by default and can be runtime (re-)started
 148           via:
 149
 150               echo 0 > /debugfs/tracing/tracing_max_latency
 151
 152           (Note that kernel size and overhead increases with this option
 153           enabled. This option and the preempt-off timing option can be
 154           used together or separately.)
 155
 156 config PREEMPT_TRACER
 157         bool "Preemption-off Latency Tracer"
 158         default n
 159         depends on GENERIC_TIME
 160         depends on PREEMPT
 161         select GENERIC_TRACER
 162         select TRACER_MAX_TRACE
 163         help
 164           This option measures the time spent in preemption off critical
 165           sections, with microsecond accuracy.
 166
 167           The default measurement method is a maximum search, which is
 168           disabled by default and can be runtime (re-)started
 169           via:
 170
 171               echo 0 > /debugfs/tracing/tracing_max_latency
 172
 173           (Note that kernel size and overhead increases with this option
 174           enabled. This option and the irqs-off timing option can be
 175           used together or separately.)
 176
 177 config SYSPROF_TRACER
 178         bool "Sysprof Tracer"
 179         depends on X86
 180         select GENERIC_TRACER
 181         select CONTEXT_SWITCH_TRACER
 182         help
 183           This tracer provides the trace needed by the 'Sysprof' userspace
 184           tool.
 185
 186 config SCHED_TRACER
 187         bool "Scheduling Latency Tracer"
 188         select GENERIC_TRACER
 189         select CONTEXT_SWITCH_TRACER
 190         select TRACER_MAX_TRACE
 191         help
 192           This tracer tracks the latency of the highest priority task
 193           to be scheduled in, starting from the point it has woken up.
 194
 195 config ENABLE_DEFAULT_TRACERS
 196         bool "Trace process context switches and events"
 197         depends on !GENERIC_TRACER
 198         select TRACING
 199         help
 200           This tracer hooks to various trace points in the kernel
 201           allowing the user to pick and choose which trace point they
 202           want to trace. It also includes the sched_switch tracer plugin.
 203
 204 config FTRACE_SYSCALLS
 205         bool "Trace syscalls"
 206         depends on HAVE_FTRACE_SYSCALLS
 207         select GENERIC_TRACER
 208         select KALLSYMS
 209         help
 210           Basic tracer to catch the syscall entry and exit events.
 211
 212 config BOOT_TRACER
 213         bool "Trace boot initcalls"
 214         select GENERIC_TRACER
 215         select CONTEXT_SWITCH_TRACER
 216         help
 217           This tracer helps developers to optimize boot times: it records
 218           the timings of the initcalls and traces key events and the identity
 219           of tasks that can cause boot delays, such as context-switches.
 220
 221           Its aim is to be parsed by the /scripts/bootgraph.pl tool to
 222           produce pretty graphics about boot inefficiencies, giving a visual
 223           representation of the delays during initcalls - but the raw
 224           /debug/tracing/trace text output is readable too.
 225
 226           You must pass in ftrace=initcall to the kernel command line
 227           to enable this on bootup.
 228
 229 config TRACE_BRANCH_PROFILING
 230         bool
 231         select GENERIC_TRACER
 232
 233 choice
 234         prompt "Branch Profiling"
 235         default BRANCH_PROFILE_NONE
 236         help
 237          The branch profiling is a software profiler. It will add hooks
 238          into the C conditionals to test which path a branch takes.
 239
 240          The likely/unlikely profiler only looks at the conditions that
 241          are annotated with a likely or unlikely macro.
 242
 243          The "all branch" profiler will profile every if statement in the
 244          kernel. This profiler will also enable the likely/unlikely
 245          profiler as well.
 246
 247          Either of the above profilers add a bit of overhead to the system.
 248          If unsure choose "No branch profiling".
 249
 250 config BRANCH_PROFILE_NONE
 251         bool "No branch profiling"
 252         help
 253          No branch profiling. Branch profiling adds a bit of overhead.
 254          Only enable it if you want to analyse the branching behavior.
 255          Otherwise keep it disabled.
 256
 257 config PROFILE_ANNOTATED_BRANCHES
 258         bool "Trace likely/unlikely profiler"
 259         select TRACE_BRANCH_PROFILING
 260         help
 261           This tracer profiles all the the likely and unlikely macros
 262           in the kernel. It will display the results in:
 263
 264           /debugfs/tracing/profile_annotated_branch
 265
 266           Note: this will add a significant overhead, only turn this
 267           on if you need to profile the system's use of these macros.
 268
 269 config PROFILE_ALL_BRANCHES
 270         bool "Profile all if conditionals"
 271         select TRACE_BRANCH_PROFILING
 272         help
 273           This tracer profiles all branch conditions. Every if ()
 274           taken in the kernel is recorded whether it hit or miss.
 275           The results will be displayed in:
 276
 277           /debugfs/tracing/profile_branch
 278
 279           This option also enables the likely/unlikely profiler.
 280
 281           This configuration, when enabled, will impose a great overhead
 282           on the system. This should only be enabled when the system
 283           is to be analyzed
 284 endchoice
 285
 286 config TRACING_BRANCHES
 287         bool
 288         help
 289           Selected by tracers that will trace the likely and unlikely
 290           conditions. This prevents the tracers themselves from being
 291           profiled. Profiling the tracing infrastructure can only happen
 292           when the likelys and unlikelys are not being traced.
 293
 294 config BRANCH_TRACER
 295         bool "Trace likely/unlikely instances"
 296         depends on TRACE_BRANCH_PROFILING
 297         select TRACING_BRANCHES
 298         help
 299           This traces the events of likely and unlikely condition
 300           calls in the kernel.  The difference between this and the
 301           "Trace likely/unlikely profiler" is that this is not a
 302           histogram of the callers, but actually places the calling
 303           events into a running trace buffer to see when and where the
 304           events happened, as well as their results.
 305
 306           Say N if unsure.
 307
 308 config POWER_TRACER
 309         bool "Trace power consumption behavior"
 310         depends on X86
 311         select GENERIC_TRACER
 312         help
 313           This tracer helps developers to analyze and optimize the kernels
 314           power management decisions, specifically the C-state and P-state
 315           behavior.
 316
 317
 318 config STACK_TRACER
 319         bool "Trace max stack"
 320         depends on HAVE_FUNCTION_TRACER
 321         select FUNCTION_TRACER
 322         select STACKTRACE
 323         select KALLSYMS
 324         help
 325           This special tracer records the maximum stack footprint of the
 326           kernel and displays it in debugfs/tracing/stack_trace.
 327
 328           This tracer works by hooking into every function call that the
 329           kernel executes, and keeping a maximum stack depth value and
 330           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 331           then it will not have any overhead while the stack tracer
 332           is disabled.
 333
 334           To enable the stack tracer on bootup, pass in 'stacktrace'
 335           on the kernel command line.
 336
 337           The stack tracer can also be enabled or disabled via the
 338           sysctl kernel.stack_tracer_enabled
 339
 340           Say N if unsure.
 341
 342 config HW_BRANCH_TRACER
 343         depends on HAVE_HW_BRANCH_TRACER
 344         bool "Trace hw branches"
 345         select GENERIC_TRACER
 346         help
 347           This tracer records all branches on the system in a circular
 348           buffer giving access to the last N branches for each cpu.
 349
 350 config KMEMTRACE
 351         bool "Trace SLAB allocations"
 352         select GENERIC_TRACER
 353         help
 354           kmemtrace provides tracing for slab allocator functions, such as
 355           kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
 356           data is then fed to the userspace application in order to analyse
 357           allocation hotspots, internal fragmentation and so on, making it
 358           possible to see how well an allocator performs, as well as debug
 359           and profile kernel code.
 360
 361           This requires an userspace application to use. See
 362           Documentation/trace/kmemtrace.txt for more information.
 363
 364           Saying Y will make the kernel somewhat larger and slower. However,
 365           if you disable kmemtrace at run-time or boot-time, the performance
 366           impact is minimal (depending on the arch the kernel is built for).
 367
 368           If unsure, say N.
 369
 370 config WORKQUEUE_TRACER
 371         bool "Trace workqueues"
 372         select GENERIC_TRACER
 373         help
 374           The workqueue tracer provides some statistical informations
 375           about each cpu workqueue thread such as the number of the
 376           works inserted and executed since their creation. It can help
 377           to evaluate the amount of work each of them have to perform.
 378           For example it can help a developer to decide whether he should
 379           choose a per cpu workqueue instead of a singlethreaded one.
 380
 381 config BLK_DEV_IO_TRACE
 382         bool "Support for tracing block io actions"
 383         depends on SYSFS
 384         depends on BLOCK
 385         select RELAY
 386         select DEBUG_FS
 387         select TRACEPOINTS
 388         select GENERIC_TRACER
 389         select STACKTRACE
 390         help
 391           Say Y here if you want to be able to trace the block layer actions
 392           on a given queue. Tracing allows you to see any traffic happening
 393           on a block device queue. For more information (and the userspace
 394           support tools needed), fetch the blktrace tools from:
 395
 396           git://git.kernel.dk/blktrace.git
 397
 398           Tracing also is possible using the ftrace interface, e.g.:
 399
 400             echo 1 > /sys/block/sda/sda1/trace/enable
 401             echo blk > /sys/kernel/debug/tracing/current_tracer
 402             cat /sys/kernel/debug/tracing/trace_pipe
 403
 404           If unsure, say N.
 405
 406 config DYNAMIC_FTRACE
 407         bool "enable/disable ftrace tracepoints dynamically"
 408         depends on FUNCTION_TRACER
 409         depends on HAVE_DYNAMIC_FTRACE
 410         default y
 411         help
 412          This option will modify all the calls to ftrace dynamically
 413          (will patch them out of the binary image and replaces them
 414          with a No-Op instruction) as they are called. A table is
 415          created to dynamically enable them again.
 416
 417          This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
 418          has native performance as long as no tracing is active.
 419
 420          The changes to the code are done by a kernel thread that
 421          wakes up once a second and checks to see if any ftrace calls
 422          were made. If so, it runs stop_machine (stops all CPUS)
 423          and modifies the code to jump over the call to ftrace.
 424
 425 config FUNCTION_PROFILER
 426         bool "Kernel function profiler"
 427         depends on FUNCTION_TRACER
 428         default n
 429         help
 430          This option enables the kernel function profiler. A file is created
 431          in debugfs called function_profile_enabled which defaults to zero.
 432          When a 1 is echoed into this file profiling begins, and when a
 433          zero is entered, profiling stops. A file in the trace_stats
 434          directory called functions, that show the list of functions that
 435          have been hit and their counters.
 436
 437          If in doubt, say N
 438
 439 config FTRACE_MCOUNT_RECORD
 440         def_bool y
 441         depends on DYNAMIC_FTRACE
 442         depends on HAVE_FTRACE_MCOUNT_RECORD
 443
 444 config FTRACE_SELFTEST
 445         bool
 446
 447 config FTRACE_STARTUP_TEST
 448         bool "Perform a startup test on ftrace"
 449         depends on GENERIC_TRACER
 450         select FTRACE_SELFTEST
 451         help
 452           This option performs a series of startup tests on ftrace. On bootup
 453           a series of tests are made to verify that the tracer is
 454           functioning properly. It will do tests on all the configured
 455           tracers of ftrace.
 456
 457 config MMIOTRACE
 458         bool "Memory mapped IO tracing"
 459         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 460         select GENERIC_TRACER
 461         help
 462           Mmiotrace traces Memory Mapped I/O access and is meant for
 463           debugging and reverse engineering. It is called from the ioremap
 464           implementation and works via page faults. Tracing is disabled by
 465           default and can be enabled at run-time.
 466
 467           See Documentation/trace/mmiotrace.txt.
 468           If you are not helping to develop drivers, say N.
 469
 470 config MMIOTRACE_TEST
 471         tristate "Test module for mmiotrace"
 472         depends on MMIOTRACE && m
 473         help
 474           This is a dumb module for testing mmiotrace. It is very dangerous
 475           as it will write garbage to IO memory starting at a given address.
 476           However, it should be safe to use on e.g. unused portion of VRAM.
 477
 478           Say N, unless you absolutely know what you are doing.
 479
 480 config RING_BUFFER_BENCHMARK
 481         tristate "Ring buffer benchmark stress tester"
 482         depends on RING_BUFFER
 483         help
 484           This option creates a test to stress the ring buffer and bench mark it.
 485           It creates its own ring buffer such that it will not interfer with
 486           any other users of the ring buffer (such as ftrace). It then creates
 487           a producer and consumer that will run for 10 seconds and sleep for
 488           10 seconds. Each interval it will print out the number of events
 489           it recorded and give a rough estimate of how long each iteration took.
 490
 491           It does not disable interrupts or raise its priority, so it may be
 492           affected by processes that are running.
 493
 494           If unsure, say N
 495
 496 endif # FTRACE
 497
 498 endif # TRACING_SUPPORT
 499