1# 2# Architectures that offer an FUNCTION_TRACER implementation should 3# select HAVE_FUNCTION_TRACER: 4# 5 6config USER_STACKTRACE_SUPPORT 7 bool 8 9config NOP_TRACER 10 bool 11 12config HAVE_FTRACE_NMI_ENTER 13 bool 14 help 15 See Documentation/trace/ftrace-design.txt 16 17config HAVE_FUNCTION_TRACER 18 bool 19 help 20 See Documentation/trace/ftrace-design.txt 21 22config HAVE_FUNCTION_GRAPH_TRACER 23 bool 24 help 25 See Documentation/trace/ftrace-design.txt 26 27config HAVE_FUNCTION_GRAPH_FP_TEST 28 bool 29 help 30 See Documentation/trace/ftrace-design.txt 31 32config HAVE_FUNCTION_TRACE_MCOUNT_TEST 33 bool 34 help 35 See Documentation/trace/ftrace-design.txt 36 37config HAVE_DYNAMIC_FTRACE 38 bool 39 help 40 See Documentation/trace/ftrace-design.txt 41 42config HAVE_FTRACE_MCOUNT_RECORD 43 bool 44 help 45 See Documentation/trace/ftrace-design.txt 46 47config HAVE_SYSCALL_TRACEPOINTS 48 bool 49 help 50 See Documentation/trace/ftrace-design.txt 51 52config HAVE_C_RECORDMCOUNT 53 bool 54 help 55 C version of recordmcount available? 56 57config TRACER_MAX_TRACE 58 bool 59 60config RING_BUFFER 61 bool 62 63config FTRACE_NMI_ENTER 64 bool 65 depends on HAVE_FTRACE_NMI_ENTER 66 default y 67 68config EVENT_TRACING 69 select CONTEXT_SWITCH_TRACER 70 bool 71 72config EVENT_POWER_TRACING_DEPRECATED 73 depends on EVENT_TRACING 74 bool "Deprecated power event trace API, to be removed" 75 default y 76 help 77 Provides old power event types: 78 C-state/idle accounting events: 79 power:power_start 80 power:power_end 81 and old cpufreq accounting event: 82 power:power_frequency 83 This is for userspace compatibility 84 and will vanish after 5 kernel iterations, 85 namely 3.1. 86 87config CONTEXT_SWITCH_TRACER 88 bool 89 90config RING_BUFFER_ALLOW_SWAP 91 bool 92 help 93 Allow the use of ring_buffer_swap_cpu. 94 Adds a very slight overhead to tracing when enabled. 95 96# All tracer options should select GENERIC_TRACER. For those options that are 97# enabled by all tracers (context switch and event tracer) they select TRACING. 98# This allows those options to appear when no other tracer is selected. But the 99# options do not appear when something else selects it. We need the two options 100# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the 101# hiding of the automatic options. 102 103config TRACING 104 bool 105 select DEBUG_FS 106 select RING_BUFFER 107 select STACKTRACE if STACKTRACE_SUPPORT 108 select TRACEPOINTS 109 select NOP_TRACER 110 select BINARY_PRINTF 111 select EVENT_TRACING 112 113config GENERIC_TRACER 114 bool 115 select TRACING 116 117# 118# Minimum requirements an architecture has to meet for us to 119# be able to offer generic tracing facilities: 120# 121config TRACING_SUPPORT 122 bool 123 # PPC32 has no irqflags tracing support, but it can use most of the 124 # tracers anyway, they were tested to build and work. Note that new 125 # exceptions to this list aren't welcomed, better implement the 126 # irqflags tracing for your architecture. 127 depends on TRACE_IRQFLAGS_SUPPORT || PPC32 128 depends on STACKTRACE_SUPPORT 129 default y 130 131if TRACING_SUPPORT 132 133menuconfig FTRACE 134 bool "Tracers" 135 default y if DEBUG_KERNEL 136 help 137 Enable the kernel tracing infrastructure. 138 139if FTRACE 140 141config FUNCTION_TRACER 142 bool "Kernel Function Tracer" 143 depends on HAVE_FUNCTION_TRACER 144 select FRAME_POINTER if !ARM_UNWIND && !S390 && !MICROBLAZE 145 select KALLSYMS 146 select GENERIC_TRACER 147 select CONTEXT_SWITCH_TRACER 148 help 149 Enable the kernel to trace every kernel function. This is done 150 by using a compiler feature to insert a small, 5-byte No-Operation 151 instruction at the beginning of every kernel function, which NOP 152 sequence is then dynamically patched into a tracer call when 153 tracing is enabled by the administrator. If it's runtime disabled 154 (the bootup default), then the overhead of the instructions is very 155 small and not measurable even in micro-benchmarks. 156 157config FUNCTION_GRAPH_TRACER 158 bool "Kernel Function Graph Tracer" 159 depends on HAVE_FUNCTION_GRAPH_TRACER 160 depends on FUNCTION_TRACER 161 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE 162 default y 163 help 164 Enable the kernel to trace a function at both its return 165 and its entry. 166 Its first purpose is to trace the duration of functions and 167 draw a call graph for each thread with some information like 168 the return value. This is done by setting the current return 169 address on the current task structure into a stack of calls. 170 171 172config IRQSOFF_TRACER 173 bool "Interrupts-off Latency Tracer" 174 default n 175 depends on TRACE_IRQFLAGS_SUPPORT 176 depends on !ARCH_USES_GETTIMEOFFSET 177 select TRACE_IRQFLAGS 178 select GENERIC_TRACER 179 select TRACER_MAX_TRACE 180 select RING_BUFFER_ALLOW_SWAP 181 help 182 This option measures the time spent in irqs-off critical 183 sections, with microsecond accuracy. 184 185 The default measurement method is a maximum search, which is 186 disabled by default and can be runtime (re-)started 187 via: 188 189 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 190 191 (Note that kernel size and overhead increase with this option 192 enabled. This option and the preempt-off timing option can be 193 used together or separately.) 194 195config PREEMPT_TRACER 196 bool "Preemption-off Latency Tracer" 197 default n 198 depends on !ARCH_USES_GETTIMEOFFSET 199 depends on PREEMPT 200 select GENERIC_TRACER 201 select TRACER_MAX_TRACE 202 select RING_BUFFER_ALLOW_SWAP 203 help 204 This option measures the time spent in preemption-off critical 205 sections, with microsecond accuracy. 206 207 The default measurement method is a maximum search, which is 208 disabled by default and can be runtime (re-)started 209 via: 210 211 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 212 213 (Note that kernel size and overhead increase with this option 214 enabled. This option and the irqs-off timing option can be 215 used together or separately.) 216 217config SCHED_TRACER 218 bool "Scheduling Latency Tracer" 219 select GENERIC_TRACER 220 select CONTEXT_SWITCH_TRACER 221 select TRACER_MAX_TRACE 222 help 223 This tracer tracks the latency of the highest priority task 224 to be scheduled in, starting from the point it has woken up. 225 226config ENABLE_DEFAULT_TRACERS 227 bool "Trace process context switches and events" 228 depends on !GENERIC_TRACER 229 select TRACING 230 help 231 This tracer hooks to various trace points in the kernel, 232 allowing the user to pick and choose which trace point they 233 want to trace. It also includes the sched_switch tracer plugin. 234 235config FTRACE_SYSCALLS 236 bool "Trace syscalls" 237 depends on HAVE_SYSCALL_TRACEPOINTS 238 select GENERIC_TRACER 239 select KALLSYMS 240 help 241 Basic tracer to catch the syscall entry and exit events. 242 243config TRACE_BRANCH_PROFILING 244 bool 245 select GENERIC_TRACER 246 247choice 248 prompt "Branch Profiling" 249 default BRANCH_PROFILE_NONE 250 help 251 The branch profiling is a software profiler. It will add hooks 252 into the C conditionals to test which path a branch takes. 253 254 The likely/unlikely profiler only looks at the conditions that 255 are annotated with a likely or unlikely macro. 256 257 The "all branch" profiler will profile every if-statement in the 258 kernel. This profiler will also enable the likely/unlikely 259 profiler. 260 261 Either of the above profilers adds a bit of overhead to the system. 262 If unsure, choose "No branch profiling". 263 264config BRANCH_PROFILE_NONE 265 bool "No branch profiling" 266 help 267 No branch profiling. Branch profiling adds a bit of overhead. 268 Only enable it if you want to analyse the branching behavior. 269 Otherwise keep it disabled. 270 271config PROFILE_ANNOTATED_BRANCHES 272 bool "Trace likely/unlikely profiler" 273 select TRACE_BRANCH_PROFILING 274 help 275 This tracer profiles all the the likely and unlikely macros 276 in the kernel. It will display the results in: 277 278 /sys/kernel/debug/tracing/trace_stat/branch_annotated 279 280 Note: this will add a significant overhead; only turn this 281 on if you need to profile the system's use of these macros. 282 283config PROFILE_ALL_BRANCHES 284 bool "Profile all if conditionals" 285 select TRACE_BRANCH_PROFILING 286 help 287 This tracer profiles all branch conditions. Every if () 288 taken in the kernel is recorded whether it hit or miss. 289 The results will be displayed in: 290 291 /sys/kernel/debug/tracing/trace_stat/branch_all 292 293 This option also enables the likely/unlikely profiler. 294 295 This configuration, when enabled, will impose a great overhead 296 on the system. This should only be enabled when the system 297 is to be analyzed in much detail. 298endchoice 299 300config TRACING_BRANCHES 301 bool 302 help 303 Selected by tracers that will trace the likely and unlikely 304 conditions. This prevents the tracers themselves from being 305 profiled. Profiling the tracing infrastructure can only happen 306 when the likelys and unlikelys are not being traced. 307 308config BRANCH_TRACER 309 bool "Trace likely/unlikely instances" 310 depends on TRACE_BRANCH_PROFILING 311 select TRACING_BRANCHES 312 help 313 This traces the events of likely and unlikely condition 314 calls in the kernel. The difference between this and the 315 "Trace likely/unlikely profiler" is that this is not a 316 histogram of the callers, but actually places the calling 317 events into a running trace buffer to see when and where the 318 events happened, as well as their results. 319 320 Say N if unsure. 321 322config STACK_TRACER 323 bool "Trace max stack" 324 depends on HAVE_FUNCTION_TRACER 325 select FUNCTION_TRACER 326 select STACKTRACE 327 select KALLSYMS 328 help 329 This special tracer records the maximum stack footprint of the 330 kernel and displays it in /sys/kernel/debug/tracing/stack_trace. 331 332 This tracer works by hooking into every function call that the 333 kernel executes, and keeping a maximum stack depth value and 334 stack-trace saved. If this is configured with DYNAMIC_FTRACE 335 then it will not have any overhead while the stack tracer 336 is disabled. 337 338 To enable the stack tracer on bootup, pass in 'stacktrace' 339 on the kernel command line. 340 341 The stack tracer can also be enabled or disabled via the 342 sysctl kernel.stack_tracer_enabled 343 344 Say N if unsure. 345 346config BLK_DEV_IO_TRACE 347 bool "Support for tracing block IO actions" 348 depends on SYSFS 349 depends on BLOCK 350 select RELAY 351 select DEBUG_FS 352 select TRACEPOINTS 353 select GENERIC_TRACER 354 select STACKTRACE 355 help 356 Say Y here if you want to be able to trace the block layer actions 357 on a given queue. Tracing allows you to see any traffic happening 358 on a block device queue. For more information (and the userspace 359 support tools needed), fetch the blktrace tools from: 360 361 git://git.kernel.dk/blktrace.git 362 363 Tracing also is possible using the ftrace interface, e.g.: 364 365 echo 1 > /sys/block/sda/sda1/trace/enable 366 echo blk > /sys/kernel/debug/tracing/current_tracer 367 cat /sys/kernel/debug/tracing/trace_pipe 368 369 If unsure, say N. 370 371config KPROBE_EVENT 372 depends on KPROBES 373 depends on HAVE_REGS_AND_STACK_ACCESS_API 374 bool "Enable kprobes-based dynamic events" 375 select TRACING 376 default y 377 help 378 This allows the user to add tracing events (similar to tracepoints) 379 on the fly via the ftrace interface. See 380 Documentation/trace/kprobetrace.txt for more details. 381 382 Those events can be inserted wherever kprobes can probe, and record 383 various register and memory values. 384 385 This option is also required by perf-probe subcommand of perf tools. 386 If you want to use perf tools, this option is strongly recommended. 387 388config DYNAMIC_FTRACE 389 bool "enable/disable ftrace tracepoints dynamically" 390 depends on FUNCTION_TRACER 391 depends on HAVE_DYNAMIC_FTRACE 392 default y 393 help 394 This option will modify all the calls to ftrace dynamically 395 (will patch them out of the binary image and replace them 396 with a No-Op instruction) as they are called. A table is 397 created to dynamically enable them again. 398 399 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 400 otherwise has native performance as long as no tracing is active. 401 402 The changes to the code are done by a kernel thread that 403 wakes up once a second and checks to see if any ftrace calls 404 were made. If so, it runs stop_machine (stops all CPUS) 405 and modifies the code to jump over the call to ftrace. 406 407config FUNCTION_PROFILER 408 bool "Kernel function profiler" 409 depends on FUNCTION_TRACER 410 default n 411 help 412 This option enables the kernel function profiler. A file is created 413 in debugfs called function_profile_enabled which defaults to zero. 414 When a 1 is echoed into this file profiling begins, and when a 415 zero is entered, profiling stops. A "functions" file is created in 416 the trace_stats directory; this file shows the list of functions that 417 have been hit and their counters. 418 419 If in doubt, say N. 420 421config FTRACE_MCOUNT_RECORD 422 def_bool y 423 depends on DYNAMIC_FTRACE 424 depends on HAVE_FTRACE_MCOUNT_RECORD 425 426config FTRACE_SELFTEST 427 bool 428 429config FTRACE_STARTUP_TEST 430 bool "Perform a startup test on ftrace" 431 depends on GENERIC_TRACER 432 select FTRACE_SELFTEST 433 help 434 This option performs a series of startup tests on ftrace. On bootup 435 a series of tests are made to verify that the tracer is 436 functioning properly. It will do tests on all the configured 437 tracers of ftrace. 438 439config EVENT_TRACE_TEST_SYSCALLS 440 bool "Run selftest on syscall events" 441 depends on FTRACE_STARTUP_TEST 442 help 443 This option will also enable testing every syscall event. 444 It only enables the event and disables it and runs various loads 445 with the event enabled. This adds a bit more time for kernel boot 446 up since it runs this on every system call defined. 447 448 TBD - enable a way to actually call the syscalls as we test their 449 events 450 451config MMIOTRACE 452 bool "Memory mapped IO tracing" 453 depends on HAVE_MMIOTRACE_SUPPORT && PCI 454 select GENERIC_TRACER 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 464config 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 474config RING_BUFFER_BENCHMARK 475 tristate "Ring buffer benchmark stress tester" 476 depends on RING_BUFFER 477 help 478 This option creates a test to stress the ring buffer and benchmark it. 479 It creates its own ring buffer such that it will not interfere with 480 any other users of the ring buffer (such as ftrace). It then creates 481 a producer and consumer that will run for 10 seconds and sleep for 482 10 seconds. Each interval it will print out the number of events 483 it recorded and give a rough estimate of how long each iteration took. 484 485 It does not disable interrupts or raise its priority, so it may be 486 affected by processes that are running. 487 488 If unsure, say N. 489 490endif # FTRACE 491 492endif # TRACING_SUPPORT 493 494