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 TRACER_MAX_TRACE
  53         bool
  54
  55 config RING_BUFFER
  56         bool
  57
  58 config FTRACE_NMI_ENTER
  59        bool
  60        depends on HAVE_FTRACE_NMI_ENTER
  61        default y
  62
  63 config EVENT_TRACING
  64         select CONTEXT_SWITCH_TRACER
  65         bool
  66
  67 config CONTEXT_SWITCH_TRACER
  68         bool
  69
  70 config RING_BUFFER_ALLOW_SWAP
  71         bool
  72         help
  73          Allow the use of ring_buffer_swap_cpu.
  74          Adds a very slight overhead to tracing when enabled.
  75
  76 # All tracer options should select GENERIC_TRACER. For those options that are
  77 # enabled by all tracers (context switch and event tracer) they select TRACING.
  78 # This allows those options to appear when no other tracer is selected. But the
  79 # options do not appear when something else selects it. We need the two options
  80 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
  81 # hiding of the automatic options.
  82
  83 config TRACING
  84         bool
  85         select DEBUG_FS
  86         select RING_BUFFER
  87         select STACKTRACE if STACKTRACE_SUPPORT
  88         select TRACEPOINTS
  89         select NOP_TRACER
  90         select BINARY_PRINTF
  91         select EVENT_TRACING
  92
  93 config GENERIC_TRACER
  94         bool
  95         select TRACING
  96
  97 #
  98 # Minimum requirements an architecture has to meet for us to
  99 # be able to offer generic tracing facilities:
 100 #
 101 config TRACING_SUPPORT
 102         bool
 103         # PPC32 has no irqflags tracing support, but it can use most of the
 104         # tracers anyway, they were tested to build and work. Note that new
 105         # exceptions to this list aren't welcomed, better implement the
 106         # irqflags tracing for your architecture.
 107         depends on TRACE_IRQFLAGS_SUPPORT || PPC32
 108         depends on STACKTRACE_SUPPORT
 109         default y
 110
 111 if TRACING_SUPPORT
 112
 113 menuconfig FTRACE
 114         bool "Tracers"
 115         default y if DEBUG_KERNEL
 116         help
 117           Enable the kernel tracing infrastructure.
 118
 119 if FTRACE
 120
 121 config FUNCTION_TRACER
 122         bool "Kernel Function Tracer"
 123         depends on HAVE_FUNCTION_TRACER
 124         select FRAME_POINTER
 125         select KALLSYMS
 126         select GENERIC_TRACER
 127         select CONTEXT_SWITCH_TRACER
 128         help
 129           Enable the kernel to trace every kernel function. This is done
 130           by using a compiler feature to insert a small, 5-byte No-Operation
 131           instruction at the beginning of every kernel function, which NOP
 132           sequence is then dynamically patched into a tracer call when
 133           tracing is enabled by the administrator. If it's runtime disabled
 134           (the bootup default), then the overhead of the instructions is very
 135           small and not measurable even in micro-benchmarks.
 136
 137 config FUNCTION_GRAPH_TRACER
 138         bool "Kernel Function Graph Tracer"
 139         depends on HAVE_FUNCTION_GRAPH_TRACER
 140         depends on FUNCTION_TRACER
 141         depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
 142         default y
 143         help
 144           Enable the kernel to trace a function at both its return
 145           and its entry.
 146           Its first purpose is to trace the duration of functions and
 147           draw a call graph for each thread with some information like
 148           the return value. This is done by setting the current return
 149           address on the current task structure into a stack of calls.
 150
 151
 152 config IRQSOFF_TRACER
 153         bool "Interrupts-off Latency Tracer"
 154         default n
 155         depends on TRACE_IRQFLAGS_SUPPORT
 156         depends on !ARCH_USES_GETTIMEOFFSET
 157         select TRACE_IRQFLAGS
 158         select GENERIC_TRACER
 159         select TRACER_MAX_TRACE
 160         select RING_BUFFER_ALLOW_SWAP
 161         help
 162           This option measures the time spent in irqs-off critical
 163           sections, with microsecond accuracy.
 164
 165           The default measurement method is a maximum search, which is
 166           disabled by default and can be runtime (re-)started
 167           via:
 168
 169               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 170
 171           (Note that kernel size and overhead increase with this option
 172           enabled. This option and the preempt-off timing option can be
 173           used together or separately.)
 174
 175 config PREEMPT_TRACER
 176         bool "Preemption-off Latency Tracer"
 177         default n
 178         depends on !ARCH_USES_GETTIMEOFFSET
 179         depends on PREEMPT
 180         select GENERIC_TRACER
 181         select TRACER_MAX_TRACE
 182         select RING_BUFFER_ALLOW_SWAP
 183         help
 184           This option measures the time spent in preemption-off critical
 185           sections, with microsecond accuracy.
 186
 187           The default measurement method is a maximum search, which is
 188           disabled by default and can be runtime (re-)started
 189           via:
 190
 191               echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
 192
 193           (Note that kernel size and overhead increase with this option
 194           enabled. This option and the irqs-off timing option can be
 195           used together or separately.)
 196
 197 config SCHED_TRACER
 198         bool "Scheduling Latency Tracer"
 199         select GENERIC_TRACER
 200         select CONTEXT_SWITCH_TRACER
 201         select TRACER_MAX_TRACE
 202         help
 203           This tracer tracks the latency of the highest priority task
 204           to be scheduled in, starting from the point it has woken up.
 205
 206 config ENABLE_DEFAULT_TRACERS
 207         bool "Trace process context switches and events"
 208         depends on !GENERIC_TRACER
 209         select TRACING
 210         help
 211           This tracer hooks to various trace points in the kernel,
 212           allowing the user to pick and choose which trace point they
 213           want to trace. It also includes the sched_switch tracer plugin.
 214
 215 config FTRACE_SYSCALLS
 216         bool "Trace syscalls"
 217         depends on HAVE_SYSCALL_TRACEPOINTS
 218         select GENERIC_TRACER
 219         select KALLSYMS
 220         help
 221           Basic tracer to catch the syscall entry and exit events.
 222
 223 config TRACE_BRANCH_PROFILING
 224         bool
 225         select GENERIC_TRACER
 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.
 240
 241          Either of the above profilers adds 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           /sys/kernel/debug/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           /sys/kernel/debug/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 in much detail.
 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 STACK_TRACER
 303         bool "Trace max stack"
 304         depends on HAVE_FUNCTION_TRACER
 305         select FUNCTION_TRACER
 306         select STACKTRACE
 307         select KALLSYMS
 308         help
 309           This special tracer records the maximum stack footprint of the
 310           kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
 311
 312           This tracer works by hooking into every function call that the
 313           kernel executes, and keeping a maximum stack depth value and
 314           stack-trace saved.  If this is configured with DYNAMIC_FTRACE
 315           then it will not have any overhead while the stack tracer
 316           is disabled.
 317
 318           To enable the stack tracer on bootup, pass in 'stacktrace'
 319           on the kernel command line.
 320
 321           The stack tracer can also be enabled or disabled via the
 322           sysctl kernel.stack_tracer_enabled
 323
 324           Say N if unsure.
 325
 326 config BLK_DEV_IO_TRACE
 327         bool "Support for tracing block IO actions"
 328         depends on SYSFS
 329         depends on BLOCK
 330         select RELAY
 331         select DEBUG_FS
 332         select TRACEPOINTS
 333         select GENERIC_TRACER
 334         select STACKTRACE
 335         help
 336           Say Y here if you want to be able to trace the block layer actions
 337           on a given queue. Tracing allows you to see any traffic happening
 338           on a block device queue. For more information (and the userspace
 339           support tools needed), fetch the blktrace tools from:
 340
 341           git://git.kernel.dk/blktrace.git
 342
 343           Tracing also is possible using the ftrace interface, e.g.:
 344
 345             echo 1 > /sys/block/sda/sda1/trace/enable
 346             echo blk > /sys/kernel/debug/tracing/current_tracer
 347             cat /sys/kernel/debug/tracing/trace_pipe
 348
 349           If unsure, say N.
 350
 351 config KPROBE_EVENT
 352         depends on KPROBES
 353         depends on HAVE_REGS_AND_STACK_ACCESS_API
 354         bool "Enable kprobes-based dynamic events"
 355         select TRACING
 356         default y
 357         help
 358           This allows the user to add tracing events (similar to tracepoints)
 359           on the fly via the ftrace interface. See
 360           Documentation/trace/kprobetrace.txt for more details.
 361
 362           Those events can be inserted wherever kprobes can probe, and record
 363           various register and memory values.
 364
 365           This option is also required by perf-probe subcommand of perf tools.
 366           If you want to use perf tools, this option is strongly recommended.
 367
 368 config DYNAMIC_FTRACE
 369         bool "enable/disable ftrace tracepoints dynamically"
 370         depends on FUNCTION_TRACER
 371         depends on HAVE_DYNAMIC_FTRACE
 372         default y
 373         help
 374           This option will modify all the calls to ftrace dynamically
 375           (will patch them out of the binary image and replace them
 376           with a No-Op instruction) as they are called. A table is
 377           created to dynamically enable them again.
 378
 379           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
 380           otherwise has native performance as long as no tracing is active.
 381
 382           The changes to the code are done by a kernel thread that
 383           wakes up once a second and checks to see if any ftrace calls
 384           were made. If so, it runs stop_machine (stops all CPUS)
 385           and modifies the code to jump over the call to ftrace.
 386
 387 config FUNCTION_PROFILER
 388         bool "Kernel function profiler"
 389         depends on FUNCTION_TRACER
 390         default n
 391         help
 392           This option enables the kernel function profiler. A file is created
 393           in debugfs called function_profile_enabled which defaults to zero.
 394           When a 1 is echoed into this file profiling begins, and when a
 395           zero is entered, profiling stops. A "functions" file is created in
 396           the trace_stats directory; this file shows the list of functions that
 397           have been hit and their counters.
 398
 399           If in doubt, say N.
 400
 401 config FTRACE_MCOUNT_RECORD
 402         def_bool y
 403         depends on DYNAMIC_FTRACE
 404         depends on HAVE_FTRACE_MCOUNT_RECORD
 405
 406 config FTRACE_SELFTEST
 407         bool
 408
 409 config FTRACE_STARTUP_TEST
 410         bool "Perform a startup test on ftrace"
 411         depends on GENERIC_TRACER
 412         select FTRACE_SELFTEST
 413         help
 414           This option performs a series of startup tests on ftrace. On bootup
 415           a series of tests are made to verify that the tracer is
 416           functioning properly. It will do tests on all the configured
 417           tracers of ftrace.
 418
 419 config EVENT_TRACE_TEST_SYSCALLS
 420         bool "Run selftest on syscall events"
 421         depends on FTRACE_STARTUP_TEST
 422         help
 423          This option will also enable testing every syscall event.
 424          It only enables the event and disables it and runs various loads
 425          with the event enabled. This adds a bit more time for kernel boot
 426          up since it runs this on every system call defined.
 427
 428          TBD - enable a way to actually call the syscalls as we test their
 429                events
 430
 431 config MMIOTRACE
 432         bool "Memory mapped IO tracing"
 433         depends on HAVE_MMIOTRACE_SUPPORT && PCI
 434         select GENERIC_TRACER
 435         help
 436           Mmiotrace traces Memory Mapped I/O access and is meant for
 437           debugging and reverse engineering. It is called from the ioremap
 438           implementation and works via page faults. Tracing is disabled by
 439           default and can be enabled at run-time.
 440
 441           See Documentation/trace/mmiotrace.txt.
 442           If you are not helping to develop drivers, say N.
 443
 444 config MMIOTRACE_TEST
 445         tristate "Test module for mmiotrace"
 446         depends on MMIOTRACE && m
 447         help
 448           This is a dumb module for testing mmiotrace. It is very dangerous
 449           as it will write garbage to IO memory starting at a given address.
 450           However, it should be safe to use on e.g. unused portion of VRAM.
 451
 452           Say N, unless you absolutely know what you are doing.
 453
 454 config RING_BUFFER_BENCHMARK
 455         tristate "Ring buffer benchmark stress tester"
 456         depends on RING_BUFFER
 457         help
 458           This option creates a test to stress the ring buffer and benchmark it.
 459           It creates its own ring buffer such that it will not interfere with
 460           any other users of the ring buffer (such as ftrace). It then creates
 461           a producer and consumer that will run for 10 seconds and sleep for
 462           10 seconds. Each interval it will print out the number of events
 463           it recorded and give a rough estimate of how long each iteration took.
 464
 465           It does not disable interrupts or raise its priority, so it may be
 466           affected by processes that are running.
 467
 468           If unsure, say N.
 469
 470 endif # FTRACE
 471
 472 endif # TRACING_SUPPORT
 473