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 An arch may pass in a unique value (frame pointer) to both the 31 entering and exiting of a function. On exit, the value is compared 32 and if it does not match, then it will panic the kernel. 33 34config HAVE_FUNCTION_TRACE_MCOUNT_TEST 35 bool 36 help 37 See Documentation/trace/ftrace-design.txt 38 39config HAVE_DYNAMIC_FTRACE 40 bool 41 help 42 See Documentation/trace/ftrace-design.txt 43 44config HAVE_FTRACE_MCOUNT_RECORD 45 bool 46 help 47 See Documentation/trace/ftrace-design.txt 48 49config HAVE_HW_BRANCH_TRACER 50 bool 51 52config HAVE_SYSCALL_TRACEPOINTS 53 bool 54 help 55 See Documentation/trace/ftrace-design.txt 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 CONTEXT_SWITCH_TRACER 73 bool 74 75config RING_BUFFER_ALLOW_SWAP 76 bool 77 help 78 Allow the use of ring_buffer_swap_cpu. 79 Adds a very slight overhead to tracing when enabled. 80 81# All tracer options should select GENERIC_TRACER. For those options that are 82# enabled by all tracers (context switch and event tracer) they select TRACING. 83# This allows those options to appear when no other tracer is selected. But the 84# options do not appear when something else selects it. We need the two options 85# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the 86# hiding of the automatic options. 87 88config TRACING 89 bool 90 select DEBUG_FS 91 select RING_BUFFER 92 select STACKTRACE if STACKTRACE_SUPPORT 93 select TRACEPOINTS 94 select NOP_TRACER 95 select BINARY_PRINTF 96 select EVENT_TRACING 97 98config GENERIC_TRACER 99 bool 100 select TRACING 101 102# 103# Minimum requirements an architecture has to meet for us to 104# be able to offer generic tracing facilities: 105# 106config TRACING_SUPPORT 107 bool 108 # PPC32 has no irqflags tracing support, but it can use most of the 109 # tracers anyway, they were tested to build and work. Note that new 110 # exceptions to this list aren't welcomed, better implement the 111 # irqflags tracing for your architecture. 112 depends on TRACE_IRQFLAGS_SUPPORT || PPC32 113 depends on STACKTRACE_SUPPORT 114 default y 115 116if TRACING_SUPPORT 117 118menuconfig FTRACE 119 bool "Tracers" 120 default y if DEBUG_KERNEL 121 help 122 Enable the kernel tracing infrastructure. 123 124if FTRACE 125 126config FUNCTION_TRACER 127 bool "Kernel Function Tracer" 128 depends on HAVE_FUNCTION_TRACER 129 select FRAME_POINTER 130 select KALLSYMS 131 select GENERIC_TRACER 132 select CONTEXT_SWITCH_TRACER 133 help 134 Enable the kernel to trace every kernel function. This is done 135 by using a compiler feature to insert a small, 5-byte No-Operation 136 instruction at the beginning of every kernel function, which NOP 137 sequence is then dynamically patched into a tracer call when 138 tracing is enabled by the administrator. If it's runtime disabled 139 (the bootup default), then the overhead of the instructions is very 140 small and not measurable even in micro-benchmarks. 141 142config FUNCTION_GRAPH_TRACER 143 bool "Kernel Function Graph Tracer" 144 depends on HAVE_FUNCTION_GRAPH_TRACER 145 depends on FUNCTION_TRACER 146 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE 147 default y 148 help 149 Enable the kernel to trace a function at both its return 150 and its entry. 151 Its first purpose is to trace the duration of functions and 152 draw a call graph for each thread with some information like 153 the return value. This is done by setting the current return 154 address on the current task structure into a stack of calls. 155 156 157config IRQSOFF_TRACER 158 bool "Interrupts-off Latency Tracer" 159 default n 160 depends on TRACE_IRQFLAGS_SUPPORT 161 depends on GENERIC_TIME 162 select TRACE_IRQFLAGS 163 select GENERIC_TRACER 164 select TRACER_MAX_TRACE 165 select RING_BUFFER_ALLOW_SWAP 166 help 167 This option measures the time spent in irqs-off critical 168 sections, with microsecond accuracy. 169 170 The default measurement method is a maximum search, which is 171 disabled by default and can be runtime (re-)started 172 via: 173 174 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 175 176 (Note that kernel size and overhead increase with this option 177 enabled. This option and the preempt-off timing option can be 178 used together or separately.) 179 180config PREEMPT_TRACER 181 bool "Preemption-off Latency Tracer" 182 default n 183 depends on GENERIC_TIME 184 depends on PREEMPT 185 select GENERIC_TRACER 186 select TRACER_MAX_TRACE 187 select RING_BUFFER_ALLOW_SWAP 188 help 189 This option measures the time spent in preemption-off critical 190 sections, with microsecond accuracy. 191 192 The default measurement method is a maximum search, which is 193 disabled by default and can be runtime (re-)started 194 via: 195 196 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 197 198 (Note that kernel size and overhead increase with this option 199 enabled. This option and the irqs-off timing option can be 200 used together or separately.) 201 202config SYSPROF_TRACER 203 bool "Sysprof Tracer" 204 depends on X86 205 select GENERIC_TRACER 206 select CONTEXT_SWITCH_TRACER 207 help 208 This tracer provides the trace needed by the 'Sysprof' userspace 209 tool. 210 211config SCHED_TRACER 212 bool "Scheduling Latency Tracer" 213 select GENERIC_TRACER 214 select CONTEXT_SWITCH_TRACER 215 select TRACER_MAX_TRACE 216 help 217 This tracer tracks the latency of the highest priority task 218 to be scheduled in, starting from the point it has woken up. 219 220config ENABLE_DEFAULT_TRACERS 221 bool "Trace process context switches and events" 222 depends on !GENERIC_TRACER 223 select TRACING 224 help 225 This tracer hooks to various trace points in the kernel, 226 allowing the user to pick and choose which trace point they 227 want to trace. It also includes the sched_switch tracer plugin. 228 229config FTRACE_SYSCALLS 230 bool "Trace syscalls" 231 depends on HAVE_SYSCALL_TRACEPOINTS 232 select GENERIC_TRACER 233 select KALLSYMS 234 help 235 Basic tracer to catch the syscall entry and exit events. 236 237config BOOT_TRACER 238 bool "Trace boot initcalls" 239 select GENERIC_TRACER 240 select CONTEXT_SWITCH_TRACER 241 help 242 This tracer helps developers to optimize boot times: it records 243 the timings of the initcalls and traces key events and the identity 244 of tasks that can cause boot delays, such as context-switches. 245 246 Its aim is to be parsed by the scripts/bootgraph.pl tool to 247 produce pretty graphics about boot inefficiencies, giving a visual 248 representation of the delays during initcalls - but the raw 249 /debug/tracing/trace text output is readable too. 250 251 You must pass in initcall_debug and ftrace=initcall to the kernel 252 command line to enable this on bootup. 253 254config TRACE_BRANCH_PROFILING 255 bool 256 select GENERIC_TRACER 257 258choice 259 prompt "Branch Profiling" 260 default BRANCH_PROFILE_NONE 261 help 262 The branch profiling is a software profiler. It will add hooks 263 into the C conditionals to test which path a branch takes. 264 265 The likely/unlikely profiler only looks at the conditions that 266 are annotated with a likely or unlikely macro. 267 268 The "all branch" profiler will profile every if-statement in the 269 kernel. This profiler will also enable the likely/unlikely 270 profiler. 271 272 Either of the above profilers adds a bit of overhead to the system. 273 If unsure, choose "No branch profiling". 274 275config BRANCH_PROFILE_NONE 276 bool "No branch profiling" 277 help 278 No branch profiling. Branch profiling adds a bit of overhead. 279 Only enable it if you want to analyse the branching behavior. 280 Otherwise keep it disabled. 281 282config PROFILE_ANNOTATED_BRANCHES 283 bool "Trace likely/unlikely profiler" 284 select TRACE_BRANCH_PROFILING 285 help 286 This tracer profiles all the the likely and unlikely macros 287 in the kernel. It will display the results in: 288 289 /sys/kernel/debug/tracing/profile_annotated_branch 290 291 Note: this will add a significant overhead; only turn this 292 on if you need to profile the system's use of these macros. 293 294config PROFILE_ALL_BRANCHES 295 bool "Profile all if conditionals" 296 select TRACE_BRANCH_PROFILING 297 help 298 This tracer profiles all branch conditions. Every if () 299 taken in the kernel is recorded whether it hit or miss. 300 The results will be displayed in: 301 302 /sys/kernel/debug/tracing/profile_branch 303 304 This option also enables the likely/unlikely profiler. 305 306 This configuration, when enabled, will impose a great overhead 307 on the system. This should only be enabled when the system 308 is to be analyzed in much detail. 309endchoice 310 311config TRACING_BRANCHES 312 bool 313 help 314 Selected by tracers that will trace the likely and unlikely 315 conditions. This prevents the tracers themselves from being 316 profiled. Profiling the tracing infrastructure can only happen 317 when the likelys and unlikelys are not being traced. 318 319config BRANCH_TRACER 320 bool "Trace likely/unlikely instances" 321 depends on TRACE_BRANCH_PROFILING 322 select TRACING_BRANCHES 323 help 324 This traces the events of likely and unlikely condition 325 calls in the kernel. The difference between this and the 326 "Trace likely/unlikely profiler" is that this is not a 327 histogram of the callers, but actually places the calling 328 events into a running trace buffer to see when and where the 329 events happened, as well as their results. 330 331 Say N if unsure. 332 333config POWER_TRACER 334 bool "Trace power consumption behavior" 335 depends on X86 336 select GENERIC_TRACER 337 help 338 This tracer helps developers to analyze and optimize the kernel's 339 power management decisions, specifically the C-state and P-state 340 behavior. 341 342config KSYM_TRACER 343 bool "Trace read and write access on kernel memory locations" 344 depends on HAVE_HW_BREAKPOINT 345 select TRACING 346 help 347 This tracer helps find read and write operations on any given kernel 348 symbol i.e. /proc/kallsyms. 349 350config PROFILE_KSYM_TRACER 351 bool "Profile all kernel memory accesses on 'watched' variables" 352 depends on KSYM_TRACER 353 help 354 This tracer profiles kernel accesses on variables watched through the 355 ksym tracer ftrace plugin. Depending upon the hardware, all read 356 and write operations on kernel variables can be monitored for 357 accesses. 358 359 The results will be displayed in: 360 /debugfs/tracing/profile_ksym 361 362 Say N if unsure. 363 364config STACK_TRACER 365 bool "Trace max stack" 366 depends on HAVE_FUNCTION_TRACER 367 select FUNCTION_TRACER 368 select STACKTRACE 369 select KALLSYMS 370 help 371 This special tracer records the maximum stack footprint of the 372 kernel and displays it in /sys/kernel/debug/tracing/stack_trace. 373 374 This tracer works by hooking into every function call that the 375 kernel executes, and keeping a maximum stack depth value and 376 stack-trace saved. If this is configured with DYNAMIC_FTRACE 377 then it will not have any overhead while the stack tracer 378 is disabled. 379 380 To enable the stack tracer on bootup, pass in 'stacktrace' 381 on the kernel command line. 382 383 The stack tracer can also be enabled or disabled via the 384 sysctl kernel.stack_tracer_enabled 385 386 Say N if unsure. 387 388config HW_BRANCH_TRACER 389 depends on HAVE_HW_BRANCH_TRACER 390 bool "Trace hw branches" 391 select GENERIC_TRACER 392 help 393 This tracer records all branches on the system in a circular 394 buffer, giving access to the last N branches for each cpu. 395 396config KMEMTRACE 397 bool "Trace SLAB allocations" 398 select GENERIC_TRACER 399 help 400 kmemtrace provides tracing for slab allocator functions, such as 401 kmalloc, kfree, kmem_cache_alloc, kmem_cache_free, etc. Collected 402 data is then fed to the userspace application in order to analyse 403 allocation hotspots, internal fragmentation and so on, making it 404 possible to see how well an allocator performs, as well as debug 405 and profile kernel code. 406 407 This requires an userspace application to use. See 408 Documentation/trace/kmemtrace.txt for more information. 409 410 Saying Y will make the kernel somewhat larger and slower. However, 411 if you disable kmemtrace at run-time or boot-time, the performance 412 impact is minimal (depending on the arch the kernel is built for). 413 414 If unsure, say N. 415 416config WORKQUEUE_TRACER 417 bool "Trace workqueues" 418 select GENERIC_TRACER 419 help 420 The workqueue tracer provides some statistical information 421 about each cpu workqueue thread such as the number of the 422 works inserted and executed since their creation. It can help 423 to evaluate the amount of work each of them has to perform. 424 For example it can help a developer to decide whether he should 425 choose a per-cpu workqueue instead of a singlethreaded one. 426 427config BLK_DEV_IO_TRACE 428 bool "Support for tracing block IO actions" 429 depends on SYSFS 430 depends on BLOCK 431 select RELAY 432 select DEBUG_FS 433 select TRACEPOINTS 434 select GENERIC_TRACER 435 select STACKTRACE 436 help 437 Say Y here if you want to be able to trace the block layer actions 438 on a given queue. Tracing allows you to see any traffic happening 439 on a block device queue. For more information (and the userspace 440 support tools needed), fetch the blktrace tools from: 441 442 git://git.kernel.dk/blktrace.git 443 444 Tracing also is possible using the ftrace interface, e.g.: 445 446 echo 1 > /sys/block/sda/sda1/trace/enable 447 echo blk > /sys/kernel/debug/tracing/current_tracer 448 cat /sys/kernel/debug/tracing/trace_pipe 449 450 If unsure, say N. 451 452config KPROBE_EVENT 453 depends on KPROBES 454 depends on X86 455 bool "Enable kprobes-based dynamic events" 456 select TRACING 457 default y 458 help 459 This allows the user to add tracing events (similar to tracepoints) 460 on the fly via the ftrace interface. See 461 Documentation/trace/kprobetrace.txt for more details. 462 463 Those events can be inserted wherever kprobes can probe, and record 464 various register and memory values. 465 466 This option is also required by perf-probe subcommand of perf tools. 467 If you want to use perf tools, this option is strongly recommended. 468 469config DYNAMIC_FTRACE 470 bool "enable/disable ftrace tracepoints dynamically" 471 depends on FUNCTION_TRACER 472 depends on HAVE_DYNAMIC_FTRACE 473 default y 474 help 475 This option will modify all the calls to ftrace dynamically 476 (will patch them out of the binary image and replace them 477 with a No-Op instruction) as they are called. A table is 478 created to dynamically enable them again. 479 480 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 481 otherwise has native performance as long as no tracing is active. 482 483 The changes to the code are done by a kernel thread that 484 wakes up once a second and checks to see if any ftrace calls 485 were made. If so, it runs stop_machine (stops all CPUS) 486 and modifies the code to jump over the call to ftrace. 487 488config FUNCTION_PROFILER 489 bool "Kernel function profiler" 490 depends on FUNCTION_TRACER 491 default n 492 help 493 This option enables the kernel function profiler. A file is created 494 in debugfs called function_profile_enabled which defaults to zero. 495 When a 1 is echoed into this file profiling begins, and when a 496 zero is entered, profiling stops. A "functions" file is created in 497 the trace_stats directory; this file shows the list of functions that 498 have been hit and their counters. 499 500 If in doubt, say N. 501 502config FTRACE_MCOUNT_RECORD 503 def_bool y 504 depends on DYNAMIC_FTRACE 505 depends on HAVE_FTRACE_MCOUNT_RECORD 506 507config FTRACE_SELFTEST 508 bool 509 510config FTRACE_STARTUP_TEST 511 bool "Perform a startup test on ftrace" 512 depends on GENERIC_TRACER 513 select FTRACE_SELFTEST 514 help 515 This option performs a series of startup tests on ftrace. On bootup 516 a series of tests are made to verify that the tracer is 517 functioning properly. It will do tests on all the configured 518 tracers of ftrace. 519 520config EVENT_TRACE_TEST_SYSCALLS 521 bool "Run selftest on syscall events" 522 depends on FTRACE_STARTUP_TEST 523 help 524 This option will also enable testing every syscall event. 525 It only enables the event and disables it and runs various loads 526 with the event enabled. This adds a bit more time for kernel boot 527 up since it runs this on every system call defined. 528 529 TBD - enable a way to actually call the syscalls as we test their 530 events 531 532config MMIOTRACE 533 bool "Memory mapped IO tracing" 534 depends on HAVE_MMIOTRACE_SUPPORT && PCI 535 select GENERIC_TRACER 536 help 537 Mmiotrace traces Memory Mapped I/O access and is meant for 538 debugging and reverse engineering. It is called from the ioremap 539 implementation and works via page faults. Tracing is disabled by 540 default and can be enabled at run-time. 541 542 See Documentation/trace/mmiotrace.txt. 543 If you are not helping to develop drivers, say N. 544 545config MMIOTRACE_TEST 546 tristate "Test module for mmiotrace" 547 depends on MMIOTRACE && m 548 help 549 This is a dumb module for testing mmiotrace. It is very dangerous 550 as it will write garbage to IO memory starting at a given address. 551 However, it should be safe to use on e.g. unused portion of VRAM. 552 553 Say N, unless you absolutely know what you are doing. 554 555config RING_BUFFER_BENCHMARK 556 tristate "Ring buffer benchmark stress tester" 557 depends on RING_BUFFER 558 help 559 This option creates a test to stress the ring buffer and benchmark it. 560 It creates its own ring buffer such that it will not interfere with 561 any other users of the ring buffer (such as ftrace). It then creates 562 a producer and consumer that will run for 10 seconds and sleep for 563 10 seconds. Each interval it will print out the number of events 564 it recorded and give a rough estimate of how long each iteration took. 565 566 It does not disable interrupts or raise its priority, so it may be 567 affected by processes that are running. 568 569 If unsure, say N. 570 571endif # FTRACE 572 573endif # TRACING_SUPPORT 574 575