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