1# SPDX-License-Identifier: GPL-2.0-only 2# 3# Architectures that offer an FUNCTION_TRACER implementation should 4# select HAVE_FUNCTION_TRACER: 5# 6 7config USER_STACKTRACE_SUPPORT 8 bool 9 10config NOP_TRACER 11 bool 12 13config HAVE_RETHOOK 14 bool 15 16config RETHOOK 17 bool 18 depends on HAVE_RETHOOK 19 help 20 Enable generic return hooking feature. This is an internal 21 API, which will be used by other function-entry hooking 22 features like fprobe and kprobes. 23 24config HAVE_FUNCTION_TRACER 25 bool 26 help 27 See Documentation/trace/ftrace-design.rst 28 29config HAVE_FUNCTION_GRAPH_TRACER 30 bool 31 help 32 See Documentation/trace/ftrace-design.rst 33 34config HAVE_FUNCTION_GRAPH_FREGS 35 bool 36 37config HAVE_FTRACE_GRAPH_FUNC 38 bool 39 help 40 True if ftrace_graph_func() is defined. 41 42config HAVE_DYNAMIC_FTRACE 43 bool 44 help 45 See Documentation/trace/ftrace-design.rst 46 47config HAVE_DYNAMIC_FTRACE_WITH_REGS 48 bool 49 50config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 51 bool 52 53config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 54 bool 55 56config HAVE_EXTRA_IPI_TRACEPOINTS 57 bool 58 help 59 For architectures that use ipi_raise, ipi_entry and ipi_exit 60 tracepoints. 61 62config HAVE_DYNAMIC_FTRACE_WITH_ARGS 63 bool 64 help 65 If this is set, then arguments and stack can be found from 66 the ftrace_regs passed into the function callback regs parameter 67 by default, even without setting the REGS flag in the ftrace_ops. 68 This allows for use of ftrace_regs_get_argument() and 69 ftrace_regs_get_stack_pointer(). 70 71config HAVE_FTRACE_REGS_HAVING_PT_REGS 72 bool 73 help 74 If this is set, ftrace_regs has pt_regs, thus it can convert to 75 pt_regs without allocating memory. 76 77config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 78 bool 79 help 80 If the architecture generates __patchable_function_entries sections 81 but does not want them included in the ftrace locations. 82 83config HAVE_SYSCALL_TRACEPOINTS 84 bool 85 help 86 See Documentation/trace/ftrace-design.rst 87 88config HAVE_FENTRY 89 bool 90 help 91 Arch supports the gcc options -pg with -mfentry 92 93config HAVE_NOP_MCOUNT 94 bool 95 help 96 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount 97 98config HAVE_OBJTOOL_MCOUNT 99 bool 100 help 101 Arch supports objtool --mcount 102 103config HAVE_OBJTOOL_NOP_MCOUNT 104 bool 105 help 106 Arch supports the objtool options --mcount with --mnop. 107 An architecture can select this if it wants to enable nop'ing 108 of ftrace locations. 109 110config HAVE_C_RECORDMCOUNT 111 bool 112 help 113 C version of recordmcount available? 114 115config HAVE_BUILDTIME_MCOUNT_SORT 116 bool 117 help 118 An architecture selects this if it sorts the mcount_loc section 119 at build time. 120 121config BUILDTIME_MCOUNT_SORT 122 bool 123 default y 124 depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE 125 help 126 Sort the mcount_loc section at build time. 127 128config TRACER_MAX_TRACE 129 bool 130 131config TRACE_CLOCK 132 bool 133 134config RING_BUFFER 135 bool 136 select TRACE_CLOCK 137 select IRQ_WORK 138 139config EVENT_TRACING 140 select CONTEXT_SWITCH_TRACER 141 select GLOB 142 bool 143 144config CONTEXT_SWITCH_TRACER 145 bool 146 147config RING_BUFFER_ALLOW_SWAP 148 bool 149 help 150 Allow the use of ring_buffer_swap_cpu. 151 Adds a very slight overhead to tracing when enabled. 152 153config PREEMPTIRQ_TRACEPOINTS 154 bool 155 depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS 156 select TRACING 157 default y 158 help 159 Create preempt/irq toggle tracepoints if needed, so that other parts 160 of the kernel can use them to generate or add hooks to them. 161 162# All tracer options should select GENERIC_TRACER. For those options that are 163# enabled by all tracers (context switch and event tracer) they select TRACING. 164# This allows those options to appear when no other tracer is selected. But the 165# options do not appear when something else selects it. We need the two options 166# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the 167# hiding of the automatic options. 168 169config TRACING 170 bool 171 select RING_BUFFER 172 select STACKTRACE if STACKTRACE_SUPPORT 173 select TRACEPOINTS 174 select NOP_TRACER 175 select BINARY_PRINTF 176 select EVENT_TRACING 177 select TRACE_CLOCK 178 select NEED_TASKS_RCU 179 180config GENERIC_TRACER 181 bool 182 select TRACING 183 184# 185# Minimum requirements an architecture has to meet for us to 186# be able to offer generic tracing facilities: 187# 188config TRACING_SUPPORT 189 bool 190 depends on TRACE_IRQFLAGS_SUPPORT 191 depends on STACKTRACE_SUPPORT 192 default y 193 194menuconfig FTRACE 195 bool "Tracers" 196 depends on TRACING_SUPPORT 197 default y if DEBUG_KERNEL 198 help 199 Enable the kernel tracing infrastructure. 200 201if FTRACE 202 203config TRACEFS_AUTOMOUNT_DEPRECATED 204 bool "Automount tracefs on debugfs [DEPRECATED]" 205 depends on TRACING 206 default y 207 help 208 The tracing interface was moved from /sys/kernel/debug/tracing 209 to /sys/kernel/tracing in 2015, but the tracing file system 210 was still automounted in /sys/kernel/debug for backward 211 compatibility with tooling. 212 213 The new interface has been around for more than 10 years and 214 the old debug mount will soon be removed. 215 216config BOOTTIME_TRACING 217 bool "Boot-time Tracing support" 218 depends on TRACING 219 select BOOT_CONFIG 220 help 221 Enable developer to setup ftrace subsystem via supplemental 222 kernel cmdline at boot time for debugging (tracing) driver 223 initialization and boot process. 224 225config FUNCTION_TRACER 226 bool "Kernel Function Tracer" 227 depends on HAVE_FUNCTION_TRACER 228 select KALLSYMS 229 select GENERIC_TRACER 230 select CONTEXT_SWITCH_TRACER 231 select GLOB 232 select NEED_TASKS_RCU 233 select TASKS_RUDE_RCU 234 help 235 Enable the kernel to trace every kernel function. This is done 236 by using a compiler feature to insert a small, 5-byte No-Operation 237 instruction at the beginning of every kernel function, which NOP 238 sequence is then dynamically patched into a tracer call when 239 tracing is enabled by the administrator. If it's runtime disabled 240 (the bootup default), then the overhead of the instructions is very 241 small and not measurable even in micro-benchmarks (at least on 242 x86, but may have impact on other architectures). 243 244config FUNCTION_GRAPH_TRACER 245 bool "Kernel Function Graph Tracer" 246 depends on HAVE_FUNCTION_GRAPH_TRACER 247 depends on FUNCTION_TRACER 248 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE 249 default y 250 help 251 Enable the kernel to trace a function at both its return 252 and its entry. 253 Its first purpose is to trace the duration of functions and 254 draw a call graph for each thread with some information like 255 the return value. This is done by setting the current return 256 address on the current task structure into a stack of calls. 257 258config FUNCTION_GRAPH_RETVAL 259 bool "Kernel Function Graph Return Value" 260 depends on HAVE_FUNCTION_GRAPH_FREGS 261 depends on FUNCTION_GRAPH_TRACER 262 default n 263 help 264 Support recording and printing the function return value when 265 using function graph tracer. It can be helpful to locate functions 266 that return errors. This feature is off by default, and you can 267 enable it via the trace option funcgraph-retval. 268 See Documentation/trace/ftrace.rst 269 270config FUNCTION_GRAPH_RETADDR 271 bool "Kernel Function Graph Return Address" 272 depends on FUNCTION_GRAPH_TRACER 273 default n 274 help 275 Support recording and printing the function return address when 276 using function graph tracer. It can be helpful to locate code line that 277 the function is called. This feature is off by default, and you can 278 enable it via the trace option funcgraph-retaddr. 279 280config FUNCTION_TRACE_ARGS 281 bool 282 depends on PROBE_EVENTS_BTF_ARGS 283 default y 284 help 285 If supported with function argument access API and BTF, then 286 the function tracer and function graph tracer will support printing 287 of function arguments. This feature is off by default, and can be 288 enabled via the trace option func-args (for the function tracer) and 289 funcgraph-args (for the function graph tracer) 290 291config DYNAMIC_FTRACE 292 bool 293 depends on FUNCTION_TRACER 294 depends on HAVE_DYNAMIC_FTRACE 295 default y 296 help 297 This option will modify all the calls to function tracing 298 dynamically (will patch them out of the binary image and 299 replace them with a No-Op instruction) on boot up. During 300 compile time, a table is made of all the locations that ftrace 301 can function trace, and this table is linked into the kernel 302 image. When this is enabled, functions can be individually 303 enabled, and the functions not enabled will not affect 304 performance of the system. 305 306 See the files in /sys/kernel/tracing: 307 available_filter_functions 308 set_ftrace_filter 309 set_ftrace_notrace 310 311 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 312 otherwise has native performance as long as no tracing is active. 313 314config DYNAMIC_FTRACE_WITH_REGS 315 def_bool y 316 depends on DYNAMIC_FTRACE 317 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS 318 319config DYNAMIC_FTRACE_WITH_DIRECT_CALLS 320 def_bool y 321 depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS 322 depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 323 324config DYNAMIC_FTRACE_WITH_CALL_OPS 325 def_bool y 326 depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 327 328config DYNAMIC_FTRACE_WITH_ARGS 329 def_bool y 330 depends on DYNAMIC_FTRACE 331 depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS 332 333config FPROBE 334 bool "Kernel Function Probe (fprobe)" 335 depends on HAVE_FUNCTION_GRAPH_FREGS && HAVE_FTRACE_GRAPH_FUNC 336 depends on DYNAMIC_FTRACE_WITH_ARGS 337 select FUNCTION_GRAPH_TRACER 338 default n 339 help 340 This option enables kernel function probe (fprobe) based on ftrace. 341 The fprobe is similar to kprobes, but probes only for kernel function 342 entries and exits. This also can probe multiple functions by one 343 fprobe. 344 345 If unsure, say N. 346 347config FUNCTION_PROFILER 348 bool "Kernel function profiler" 349 depends on FUNCTION_TRACER 350 default n 351 help 352 This option enables the kernel function profiler. A file is created 353 in debugfs called function_profile_enabled which defaults to zero. 354 When a 1 is echoed into this file profiling begins, and when a 355 zero is entered, profiling stops. A "functions" file is created in 356 the trace_stat directory; this file shows the list of functions that 357 have been hit and their counters. 358 359 If in doubt, say N. 360 361config STACK_TRACER 362 bool "Trace max stack" 363 depends on HAVE_FUNCTION_TRACER 364 select FUNCTION_TRACER 365 select STACKTRACE 366 select KALLSYMS 367 help 368 This special tracer records the maximum stack footprint of the 369 kernel and displays it in /sys/kernel/tracing/stack_trace. 370 371 This tracer works by hooking into every function call that the 372 kernel executes, and keeping a maximum stack depth value and 373 stack-trace saved. If this is configured with DYNAMIC_FTRACE 374 then it will not have any overhead while the stack tracer 375 is disabled. 376 377 To enable the stack tracer on bootup, pass in 'stacktrace' 378 on the kernel command line. 379 380 The stack tracer can also be enabled or disabled via the 381 sysctl kernel.stack_tracer_enabled 382 383 Say N if unsure. 384 385config TRACE_PREEMPT_TOGGLE 386 bool 387 help 388 Enables hooks which will be called when preemption is first disabled, 389 and last enabled. 390 391config IRQSOFF_TRACER 392 bool "Interrupts-off Latency Tracer" 393 default n 394 depends on TRACE_IRQFLAGS_SUPPORT 395 select TRACE_IRQFLAGS 396 select GENERIC_TRACER 397 select TRACER_MAX_TRACE 398 select RING_BUFFER_ALLOW_SWAP 399 select TRACER_SNAPSHOT 400 select TRACER_SNAPSHOT_PER_CPU_SWAP 401 help 402 This option measures the time spent in irqs-off critical 403 sections, with microsecond accuracy. 404 405 The default measurement method is a maximum search, which is 406 disabled by default and can be runtime (re-)started 407 via: 408 409 echo 0 > /sys/kernel/tracing/tracing_max_latency 410 411 (Note that kernel size and overhead increase with this option 412 enabled. This option and the preempt-off timing option can be 413 used together or separately.) 414 415config PREEMPT_TRACER 416 bool "Preemption-off Latency Tracer" 417 default n 418 depends on PREEMPTION 419 select GENERIC_TRACER 420 select TRACER_MAX_TRACE 421 select RING_BUFFER_ALLOW_SWAP 422 select TRACER_SNAPSHOT 423 select TRACER_SNAPSHOT_PER_CPU_SWAP 424 select TRACE_PREEMPT_TOGGLE 425 help 426 This option measures the time spent in preemption-off critical 427 sections, with microsecond accuracy. 428 429 The default measurement method is a maximum search, which is 430 disabled by default and can be runtime (re-)started 431 via: 432 433 echo 0 > /sys/kernel/tracing/tracing_max_latency 434 435 (Note that kernel size and overhead increase with this option 436 enabled. This option and the irqs-off timing option can be 437 used together or separately.) 438 439config SCHED_TRACER 440 bool "Scheduling Latency Tracer" 441 select GENERIC_TRACER 442 select CONTEXT_SWITCH_TRACER 443 select TRACER_MAX_TRACE 444 select TRACER_SNAPSHOT 445 help 446 This tracer tracks the latency of the highest priority task 447 to be scheduled in, starting from the point it has woken up. 448 449config HWLAT_TRACER 450 bool "Tracer to detect hardware latencies (like SMIs)" 451 select GENERIC_TRACER 452 select TRACER_MAX_TRACE 453 help 454 This tracer, when enabled will create one or more kernel threads, 455 depending on what the cpumask file is set to, which each thread 456 spinning in a loop looking for interruptions caused by 457 something other than the kernel. For example, if a 458 System Management Interrupt (SMI) takes a noticeable amount of 459 time, this tracer will detect it. This is useful for testing 460 if a system is reliable for Real Time tasks. 461 462 Some files are created in the tracing directory when this 463 is enabled: 464 465 hwlat_detector/width - time in usecs for how long to spin for 466 hwlat_detector/window - time in usecs between the start of each 467 iteration 468 469 A kernel thread is created that will spin with interrupts disabled 470 for "width" microseconds in every "window" cycle. It will not spin 471 for "window - width" microseconds, where the system can 472 continue to operate. 473 474 The output will appear in the trace and trace_pipe files. 475 476 When the tracer is not running, it has no affect on the system, 477 but when it is running, it can cause the system to be 478 periodically non responsive. Do not run this tracer on a 479 production system. 480 481 To enable this tracer, echo in "hwlat" into the current_tracer 482 file. Every time a latency is greater than tracing_thresh, it will 483 be recorded into the ring buffer. 484 485config OSNOISE_TRACER 486 bool "OS Noise tracer" 487 select GENERIC_TRACER 488 select TRACER_MAX_TRACE 489 help 490 In the context of high-performance computing (HPC), the Operating 491 System Noise (osnoise) refers to the interference experienced by an 492 application due to activities inside the operating system. In the 493 context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread 494 can cause noise to the system. Moreover, hardware-related jobs can 495 also cause noise, for example, via SMIs. 496 497 The osnoise tracer leverages the hwlat_detector by running a similar 498 loop with preemption, SoftIRQs and IRQs enabled, thus allowing all 499 the sources of osnoise during its execution. The osnoise tracer takes 500 note of the entry and exit point of any source of interferences, 501 increasing a per-cpu interference counter. It saves an interference 502 counter for each source of interference. The interference counter for 503 NMI, IRQs, SoftIRQs, and threads is increased anytime the tool 504 observes these interferences' entry events. When a noise happens 505 without any interference from the operating system level, the 506 hardware noise counter increases, pointing to a hardware-related 507 noise. In this way, osnoise can account for any source of 508 interference. At the end of the period, the osnoise tracer prints 509 the sum of all noise, the max single noise, the percentage of CPU 510 available for the thread, and the counters for the noise sources. 511 512 In addition to the tracer, a set of tracepoints were added to 513 facilitate the identification of the osnoise source. 514 515 The output will appear in the trace and trace_pipe files. 516 517 To enable this tracer, echo in "osnoise" into the current_tracer 518 file. 519 520config TIMERLAT_TRACER 521 bool "Timerlat tracer" 522 select OSNOISE_TRACER 523 select GENERIC_TRACER 524 help 525 The timerlat tracer aims to help the preemptive kernel developers 526 to find sources of wakeup latencies of real-time threads. 527 528 The tracer creates a per-cpu kernel thread with real-time priority. 529 The tracer thread sets a periodic timer to wakeup itself, and goes 530 to sleep waiting for the timer to fire. At the wakeup, the thread 531 then computes a wakeup latency value as the difference between 532 the current time and the absolute time that the timer was set 533 to expire. 534 535 The tracer prints two lines at every activation. The first is the 536 timer latency observed at the hardirq context before the 537 activation of the thread. The second is the timer latency observed 538 by the thread, which is the same level that cyclictest reports. The 539 ACTIVATION ID field serves to relate the irq execution to its 540 respective thread execution. 541 542 The tracer is build on top of osnoise tracer, and the osnoise: 543 events can be used to trace the source of interference from NMI, 544 IRQs and other threads. It also enables the capture of the 545 stacktrace at the IRQ context, which helps to identify the code 546 path that can cause thread delay. 547 548config MMIOTRACE 549 bool "Memory mapped IO tracing" 550 depends on HAVE_MMIOTRACE_SUPPORT && PCI 551 select GENERIC_TRACER 552 help 553 Mmiotrace traces Memory Mapped I/O access and is meant for 554 debugging and reverse engineering. It is called from the ioremap 555 implementation and works via page faults. Tracing is disabled by 556 default and can be enabled at run-time. 557 558 See Documentation/trace/mmiotrace.rst. 559 If you are not helping to develop drivers, say N. 560 561config ENABLE_DEFAULT_TRACERS 562 bool "Trace process context switches and events" 563 depends on !GENERIC_TRACER 564 select TRACING 565 help 566 This tracer hooks to various trace points in the kernel, 567 allowing the user to pick and choose which trace point they 568 want to trace. It also includes the sched_switch tracer plugin. 569 570config FTRACE_SYSCALLS 571 bool "Trace syscalls" 572 depends on HAVE_SYSCALL_TRACEPOINTS 573 select GENERIC_TRACER 574 select KALLSYMS 575 help 576 Basic tracer to catch the syscall entry and exit events. 577 578config TRACER_SNAPSHOT 579 bool "Create a snapshot trace buffer" 580 select TRACER_MAX_TRACE 581 help 582 Allow tracing users to take snapshot of the current buffer using the 583 ftrace interface, e.g.: 584 585 echo 1 > /sys/kernel/tracing/snapshot 586 cat snapshot 587 588config TRACER_SNAPSHOT_PER_CPU_SWAP 589 bool "Allow snapshot to swap per CPU" 590 depends on TRACER_SNAPSHOT 591 select RING_BUFFER_ALLOW_SWAP 592 help 593 Allow doing a snapshot of a single CPU buffer instead of a 594 full swap (all buffers). If this is set, then the following is 595 allowed: 596 597 echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot 598 599 After which, only the tracing buffer for CPU 2 was swapped with 600 the main tracing buffer, and the other CPU buffers remain the same. 601 602 When this is enabled, this adds a little more overhead to the 603 trace recording, as it needs to add some checks to synchronize 604 recording with swaps. But this does not affect the performance 605 of the overall system. This is enabled by default when the preempt 606 or irq latency tracers are enabled, as those need to swap as well 607 and already adds the overhead (plus a lot more). 608 609config TRACE_BRANCH_PROFILING 610 bool 611 select GENERIC_TRACER 612 613choice 614 prompt "Branch Profiling" 615 default BRANCH_PROFILE_NONE 616 help 617 The branch profiling is a software profiler. It will add hooks 618 into the C conditionals to test which path a branch takes. 619 620 The likely/unlikely profiler only looks at the conditions that 621 are annotated with a likely or unlikely macro. 622 623 The "all branch" profiler will profile every if-statement in the 624 kernel. This profiler will also enable the likely/unlikely 625 profiler. 626 627 Either of the above profilers adds a bit of overhead to the system. 628 If unsure, choose "No branch profiling". 629 630config BRANCH_PROFILE_NONE 631 bool "No branch profiling" 632 help 633 No branch profiling. Branch profiling adds a bit of overhead. 634 Only enable it if you want to analyse the branching behavior. 635 Otherwise keep it disabled. 636 637config PROFILE_ANNOTATED_BRANCHES 638 bool "Trace likely/unlikely profiler" 639 select TRACE_BRANCH_PROFILING 640 help 641 This tracer profiles all likely and unlikely macros 642 in the kernel. It will display the results in: 643 644 /sys/kernel/tracing/trace_stat/branch_annotated 645 646 Note: this will add a significant overhead; only turn this 647 on if you need to profile the system's use of these macros. 648 649config PROFILE_ALL_BRANCHES 650 bool "Profile all if conditionals" if !FORTIFY_SOURCE 651 select TRACE_BRANCH_PROFILING 652 help 653 This tracer profiles all branch conditions. Every if () 654 taken in the kernel is recorded whether it hit or miss. 655 The results will be displayed in: 656 657 /sys/kernel/tracing/trace_stat/branch_all 658 659 This option also enables the likely/unlikely profiler. 660 661 This configuration, when enabled, will impose a great overhead 662 on the system. This should only be enabled when the system 663 is to be analyzed in much detail. 664endchoice 665 666config TRACING_BRANCHES 667 bool 668 help 669 Selected by tracers that will trace the likely and unlikely 670 conditions. This prevents the tracers themselves from being 671 profiled. Profiling the tracing infrastructure can only happen 672 when the likelys and unlikelys are not being traced. 673 674config BRANCH_TRACER 675 bool "Trace likely/unlikely instances" 676 depends on TRACE_BRANCH_PROFILING 677 select TRACING_BRANCHES 678 help 679 This traces the events of likely and unlikely condition 680 calls in the kernel. The difference between this and the 681 "Trace likely/unlikely profiler" is that this is not a 682 histogram of the callers, but actually places the calling 683 events into a running trace buffer to see when and where the 684 events happened, as well as their results. 685 686 Say N if unsure. 687 688config BLK_DEV_IO_TRACE 689 bool "Support for tracing block IO actions" 690 depends on SYSFS 691 depends on BLOCK 692 select RELAY 693 select DEBUG_FS 694 select TRACEPOINTS 695 select GENERIC_TRACER 696 select STACKTRACE 697 help 698 Say Y here if you want to be able to trace the block layer actions 699 on a given queue. Tracing allows you to see any traffic happening 700 on a block device queue. For more information (and the userspace 701 support tools needed), fetch the blktrace tools from: 702 703 git://git.kernel.dk/blktrace.git 704 705 Tracing also is possible using the ftrace interface, e.g.: 706 707 echo 1 > /sys/block/sda/sda1/trace/enable 708 echo blk > /sys/kernel/tracing/current_tracer 709 cat /sys/kernel/tracing/trace_pipe 710 711 If unsure, say N. 712 713config FPROBE_EVENTS 714 depends on FPROBE 715 depends on HAVE_REGS_AND_STACK_ACCESS_API 716 bool "Enable fprobe-based dynamic events" 717 select TRACING 718 select PROBE_EVENTS 719 select DYNAMIC_EVENTS 720 default y 721 help 722 This allows user to add tracing events on the function entry and 723 exit via ftrace interface. The syntax is same as the kprobe events 724 and the kprobe events on function entry and exit will be 725 transparently converted to this fprobe events. 726 727config PROBE_EVENTS_BTF_ARGS 728 depends on HAVE_FUNCTION_ARG_ACCESS_API 729 depends on FPROBE_EVENTS || KPROBE_EVENTS 730 depends on DEBUG_INFO_BTF && BPF_SYSCALL 731 bool "Support BTF function arguments for probe events" 732 default y 733 help 734 The user can specify the arguments of the probe event using the names 735 of the arguments of the probed function, when the probe location is a 736 kernel function entry or a tracepoint. 737 This is available only if BTF (BPF Type Format) support is enabled. 738 739config KPROBE_EVENTS 740 depends on KPROBES 741 depends on HAVE_REGS_AND_STACK_ACCESS_API 742 bool "Enable kprobes-based dynamic events" 743 select TRACING 744 select PROBE_EVENTS 745 select DYNAMIC_EVENTS 746 default y 747 help 748 This allows the user to add tracing events (similar to tracepoints) 749 on the fly via the ftrace interface. See 750 Documentation/trace/kprobetrace.rst for more details. 751 752 Those events can be inserted wherever kprobes can probe, and record 753 various register and memory values. 754 755 This option is also required by perf-probe subcommand of perf tools. 756 If you want to use perf tools, this option is strongly recommended. 757 758config KPROBE_EVENTS_ON_NOTRACE 759 bool "Do NOT protect notrace function from kprobe events" 760 depends on KPROBE_EVENTS 761 depends on DYNAMIC_FTRACE 762 default n 763 help 764 This is only for the developers who want to debug ftrace itself 765 using kprobe events. 766 767 If kprobes can use ftrace instead of breakpoint, ftrace related 768 functions are protected from kprobe-events to prevent an infinite 769 recursion or any unexpected execution path which leads to a kernel 770 crash. 771 772 This option disables such protection and allows you to put kprobe 773 events on ftrace functions for debugging ftrace by itself. 774 Note that this might let you shoot yourself in the foot. 775 776 If unsure, say N. 777 778config UPROBE_EVENTS 779 bool "Enable uprobes-based dynamic events" 780 depends on ARCH_SUPPORTS_UPROBES 781 depends on MMU 782 depends on PERF_EVENTS 783 select UPROBES 784 select PROBE_EVENTS 785 select DYNAMIC_EVENTS 786 select TRACING 787 default y 788 help 789 This allows the user to add tracing events on top of userspace 790 dynamic events (similar to tracepoints) on the fly via the trace 791 events interface. Those events can be inserted wherever uprobes 792 can probe, and record various registers. 793 This option is required if you plan to use perf-probe subcommand 794 of perf tools on user space applications. 795 796config EPROBE_EVENTS 797 bool "Enable event-based dynamic events" 798 depends on TRACING 799 depends on HAVE_REGS_AND_STACK_ACCESS_API 800 select PROBE_EVENTS 801 select DYNAMIC_EVENTS 802 default y 803 help 804 Eprobes are dynamic events that can be placed on other existing 805 events. It can be used to limit what fields are recorded in 806 an event or even dereference a field of an event. It can 807 convert the type of an event field. For example, turn an 808 address into a string. 809 810config BPF_EVENTS 811 depends on BPF_SYSCALL 812 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS 813 bool 814 default y 815 help 816 This allows the user to attach BPF programs to kprobe, uprobe, and 817 tracepoint events. 818 819config DYNAMIC_EVENTS 820 def_bool n 821 822config PROBE_EVENTS 823 def_bool n 824 825config BPF_KPROBE_OVERRIDE 826 bool "Enable BPF programs to override a kprobed function" 827 depends on BPF_EVENTS 828 depends on FUNCTION_ERROR_INJECTION 829 default n 830 help 831 Allows BPF to override the execution of a probed function and 832 set a different return value. This is used for error injection. 833 834config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 835 bool 836 depends on DYNAMIC_FTRACE 837 838config FTRACE_MCOUNT_USE_CC 839 def_bool y 840 depends on $(cc-option,-mrecord-mcount) 841 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 842 depends on DYNAMIC_FTRACE 843 844config FTRACE_MCOUNT_USE_OBJTOOL 845 def_bool y 846 depends on HAVE_OBJTOOL_MCOUNT 847 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 848 depends on !FTRACE_MCOUNT_USE_CC 849 depends on DYNAMIC_FTRACE 850 select OBJTOOL 851 852config FTRACE_MCOUNT_USE_RECORDMCOUNT 853 def_bool y 854 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 855 depends on !FTRACE_MCOUNT_USE_CC 856 depends on !FTRACE_MCOUNT_USE_OBJTOOL 857 depends on DYNAMIC_FTRACE 858 859config TRACING_MAP 860 bool 861 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 862 help 863 tracing_map is a special-purpose lock-free map for tracing, 864 separated out as a stand-alone facility in order to allow it 865 to be shared between multiple tracers. It isn't meant to be 866 generally used outside of that context, and is normally 867 selected by tracers that use it. 868 869config SYNTH_EVENTS 870 bool "Synthetic trace events" 871 select TRACING 872 select DYNAMIC_EVENTS 873 default n 874 help 875 Synthetic events are user-defined trace events that can be 876 used to combine data from other trace events or in fact any 877 data source. Synthetic events can be generated indirectly 878 via the trace() action of histogram triggers or directly 879 by way of an in-kernel API. 880 881 See Documentation/trace/events.rst or 882 Documentation/trace/histogram.rst for details and examples. 883 884 If in doubt, say N. 885 886config USER_EVENTS 887 bool "User trace events" 888 select TRACING 889 select DYNAMIC_EVENTS 890 help 891 User trace events are user-defined trace events that 892 can be used like an existing kernel trace event. User trace 893 events are generated by writing to a tracefs file. User 894 processes can determine if their tracing events should be 895 generated by registering a value and bit with the kernel 896 that reflects when it is enabled or not. 897 898 See Documentation/trace/user_events.rst. 899 If in doubt, say N. 900 901config HIST_TRIGGERS 902 bool "Histogram triggers" 903 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 904 select TRACING_MAP 905 select TRACING 906 select DYNAMIC_EVENTS 907 select SYNTH_EVENTS 908 default n 909 help 910 Hist triggers allow one or more arbitrary trace event fields 911 to be aggregated into hash tables and dumped to stdout by 912 reading a debugfs/tracefs file. They're useful for 913 gathering quick and dirty (though precise) summaries of 914 event activity as an initial guide for further investigation 915 using more advanced tools. 916 917 Inter-event tracing of quantities such as latencies is also 918 supported using hist triggers under this option. 919 920 See Documentation/trace/histogram.rst. 921 If in doubt, say N. 922 923config TRACE_EVENT_INJECT 924 bool "Trace event injection" 925 depends on TRACING 926 help 927 Allow user-space to inject a specific trace event into the ring 928 buffer. This is mainly used for testing purpose. 929 930 If unsure, say N. 931 932config TRACEPOINT_BENCHMARK 933 bool "Add tracepoint that benchmarks tracepoints" 934 help 935 This option creates the tracepoint "benchmark:benchmark_event". 936 When the tracepoint is enabled, it kicks off a kernel thread that 937 goes into an infinite loop (calling cond_resched() to let other tasks 938 run), and calls the tracepoint. Each iteration will record the time 939 it took to write to the tracepoint and the next iteration that 940 data will be passed to the tracepoint itself. That is, the tracepoint 941 will report the time it took to do the previous tracepoint. 942 The string written to the tracepoint is a static string of 128 bytes 943 to keep the time the same. The initial string is simply a write of 944 "START". The second string records the cold cache time of the first 945 write which is not added to the rest of the calculations. 946 947 As it is a tight loop, it benchmarks as hot cache. That's fine because 948 we care most about hot paths that are probably in cache already. 949 950 An example of the output: 951 952 START 953 first=3672 [COLD CACHED] 954 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712 955 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337 956 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064 957 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411 958 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389 959 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666 960 961 962config RING_BUFFER_BENCHMARK 963 tristate "Ring buffer benchmark stress tester" 964 depends on RING_BUFFER 965 help 966 This option creates a test to stress the ring buffer and benchmark it. 967 It creates its own ring buffer such that it will not interfere with 968 any other users of the ring buffer (such as ftrace). It then creates 969 a producer and consumer that will run for 10 seconds and sleep for 970 10 seconds. Each interval it will print out the number of events 971 it recorded and give a rough estimate of how long each iteration took. 972 973 It does not disable interrupts or raise its priority, so it may be 974 affected by processes that are running. 975 976 If unsure, say N. 977 978config TRACE_EVAL_MAP_FILE 979 bool "Show eval mappings for trace events" 980 depends on TRACING 981 help 982 The "print fmt" of the trace events will show the enum/sizeof names 983 instead of their values. This can cause problems for user space tools 984 that use this string to parse the raw data as user space does not know 985 how to convert the string to its value. 986 987 To fix this, there's a special macro in the kernel that can be used 988 to convert an enum/sizeof into its value. If this macro is used, then 989 the print fmt strings will be converted to their values. 990 991 If something does not get converted properly, this option can be 992 used to show what enums/sizeof the kernel tried to convert. 993 994 This option is for debugging the conversions. A file is created 995 in the tracing directory called "eval_map" that will show the 996 names matched with their values and what trace event system they 997 belong too. 998 999 Normally, the mapping of the strings to values will be freed after 1000 boot up or module load. With this option, they will not be freed, as 1001 they are needed for the "eval_map" file. Enabling this option will 1002 increase the memory footprint of the running kernel. 1003 1004 If unsure, say N. 1005 1006config FTRACE_RECORD_RECURSION 1007 bool "Record functions that recurse in function tracing" 1008 depends on FUNCTION_TRACER 1009 help 1010 All callbacks that attach to the function tracing have some sort 1011 of protection against recursion. Even though the protection exists, 1012 it adds overhead. This option will create a file in the tracefs 1013 file system called "recursed_functions" that will list the functions 1014 that triggered a recursion. 1015 1016 This will add more overhead to cases that have recursion. 1017 1018 If unsure, say N 1019 1020config FTRACE_RECORD_RECURSION_SIZE 1021 int "Max number of recursed functions to record" 1022 default 128 1023 depends on FTRACE_RECORD_RECURSION 1024 help 1025 This defines the limit of number of functions that can be 1026 listed in the "recursed_functions" file, that lists all 1027 the functions that caused a recursion to happen. 1028 This file can be reset, but the limit can not change in 1029 size at runtime. 1030 1031config FTRACE_VALIDATE_RCU_IS_WATCHING 1032 bool "Validate RCU is on during ftrace execution" 1033 depends on FUNCTION_TRACER 1034 depends on ARCH_WANTS_NO_INSTR 1035 help 1036 All callbacks that attach to the function tracing have some sort of 1037 protection against recursion. This option is only to verify that 1038 ftrace (and other users of ftrace_test_recursion_trylock()) are not 1039 called outside of RCU, as if they are, it can cause a race. But it 1040 also has a noticeable overhead when enabled. 1041 1042 If unsure, say N 1043 1044config RING_BUFFER_RECORD_RECURSION 1045 bool "Record functions that recurse in the ring buffer" 1046 depends on FTRACE_RECORD_RECURSION 1047 # default y, because it is coupled with FTRACE_RECORD_RECURSION 1048 default y 1049 help 1050 The ring buffer has its own internal recursion. Although when 1051 recursion happens it won't cause harm because of the protection, 1052 but it does cause unwanted overhead. Enabling this option will 1053 place where recursion was detected into the ftrace "recursed_functions" 1054 file. 1055 1056 This will add more overhead to cases that have recursion. 1057 1058config GCOV_PROFILE_FTRACE 1059 bool "Enable GCOV profiling on ftrace subsystem" 1060 depends on GCOV_KERNEL 1061 help 1062 Enable GCOV profiling on ftrace subsystem for checking 1063 which functions/lines are tested. 1064 1065 If unsure, say N. 1066 1067 Note that on a kernel compiled with this config, ftrace will 1068 run significantly slower. 1069 1070config FTRACE_SELFTEST 1071 bool 1072 1073config FTRACE_STARTUP_TEST 1074 bool "Perform a startup test on ftrace" 1075 depends on GENERIC_TRACER 1076 select FTRACE_SELFTEST 1077 help 1078 This option performs a series of startup tests on ftrace. On bootup 1079 a series of tests are made to verify that the tracer is 1080 functioning properly. It will do tests on all the configured 1081 tracers of ftrace. 1082 1083config EVENT_TRACE_STARTUP_TEST 1084 bool "Run selftest on trace events" 1085 depends on FTRACE_STARTUP_TEST 1086 default y 1087 help 1088 This option performs a test on all trace events in the system. 1089 It basically just enables each event and runs some code that 1090 will trigger events (not necessarily the event it enables) 1091 This may take some time run as there are a lot of events. 1092 1093config EVENT_TRACE_TEST_SYSCALLS 1094 bool "Run selftest on syscall events" 1095 depends on EVENT_TRACE_STARTUP_TEST 1096 help 1097 This option will also enable testing every syscall event. 1098 It only enables the event and disables it and runs various loads 1099 with the event enabled. This adds a bit more time for kernel boot 1100 up since it runs this on every system call defined. 1101 1102 TBD - enable a way to actually call the syscalls as we test their 1103 events 1104 1105config FTRACE_SORT_STARTUP_TEST 1106 bool "Verify compile time sorting of ftrace functions" 1107 depends on DYNAMIC_FTRACE 1108 depends on BUILDTIME_MCOUNT_SORT 1109 help 1110 Sorting of the mcount_loc sections that is used to find the 1111 where the ftrace knows where to patch functions for tracing 1112 and other callbacks is done at compile time. But if the sort 1113 is not done correctly, it will cause non-deterministic failures. 1114 When this is set, the sorted sections will be verified that they 1115 are in deed sorted and will warn if they are not. 1116 1117 If unsure, say N 1118 1119config RING_BUFFER_STARTUP_TEST 1120 bool "Ring buffer startup self test" 1121 depends on RING_BUFFER 1122 help 1123 Run a simple self test on the ring buffer on boot up. Late in the 1124 kernel boot sequence, the test will start that kicks off 1125 a thread per cpu. Each thread will write various size events 1126 into the ring buffer. Another thread is created to send IPIs 1127 to each of the threads, where the IPI handler will also write 1128 to the ring buffer, to test/stress the nesting ability. 1129 If any anomalies are discovered, a warning will be displayed 1130 and all ring buffers will be disabled. 1131 1132 The test runs for 10 seconds. This will slow your boot time 1133 by at least 10 more seconds. 1134 1135 At the end of the test, statistics and more checks are done. 1136 It will output the stats of each per cpu buffer: What 1137 was written, the sizes, what was read, what was lost, and 1138 other similar details. 1139 1140 If unsure, say N 1141 1142config RING_BUFFER_VALIDATE_TIME_DELTAS 1143 bool "Verify ring buffer time stamp deltas" 1144 depends on RING_BUFFER 1145 help 1146 This will audit the time stamps on the ring buffer sub 1147 buffer to make sure that all the time deltas for the 1148 events on a sub buffer matches the current time stamp. 1149 This audit is performed for every event that is not 1150 interrupted, or interrupting another event. A check 1151 is also made when traversing sub buffers to make sure 1152 that all the deltas on the previous sub buffer do not 1153 add up to be greater than the current time stamp. 1154 1155 NOTE: This adds significant overhead to recording of events, 1156 and should only be used to test the logic of the ring buffer. 1157 Do not use it on production systems. 1158 1159 Only say Y if you understand what this does, and you 1160 still want it enabled. Otherwise say N 1161 1162config MMIOTRACE_TEST 1163 tristate "Test module for mmiotrace" 1164 depends on MMIOTRACE && m 1165 help 1166 This is a dumb module for testing mmiotrace. It is very dangerous 1167 as it will write garbage to IO memory starting at a given address. 1168 However, it should be safe to use on e.g. unused portion of VRAM. 1169 1170 Say N, unless you absolutely know what you are doing. 1171 1172config PREEMPTIRQ_DELAY_TEST 1173 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers" 1174 depends on m 1175 help 1176 Select this option to build a test module that can help test latency 1177 tracers by executing a preempt or irq disable section with a user 1178 configurable delay. The module busy waits for the duration of the 1179 critical section. 1180 1181 For example, the following invocation generates a burst of three 1182 irq-disabled critical sections for 500us: 1183 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3 1184 1185 What's more, if you want to attach the test on the cpu which the latency 1186 tracer is running on, specify cpu_affinity=cpu_num at the end of the 1187 command. 1188 1189 If unsure, say N 1190 1191config SYNTH_EVENT_GEN_TEST 1192 tristate "Test module for in-kernel synthetic event generation" 1193 depends on SYNTH_EVENTS && m 1194 help 1195 This option creates a test module to check the base 1196 functionality of in-kernel synthetic event definition and 1197 generation. 1198 1199 To test, insert the module, and then check the trace buffer 1200 for the generated sample events. 1201 1202 If unsure, say N. 1203 1204config KPROBE_EVENT_GEN_TEST 1205 tristate "Test module for in-kernel kprobe event generation" 1206 depends on KPROBE_EVENTS && m 1207 help 1208 This option creates a test module to check the base 1209 functionality of in-kernel kprobe event definition. 1210 1211 To test, insert the module, and then check the trace buffer 1212 for the generated kprobe events. 1213 1214 If unsure, say N. 1215 1216config HIST_TRIGGERS_DEBUG 1217 bool "Hist trigger debug support" 1218 depends on HIST_TRIGGERS 1219 help 1220 Add "hist_debug" file for each event, which when read will 1221 dump out a bunch of internal details about the hist triggers 1222 defined on that event. 1223 1224 The hist_debug file serves a couple of purposes: 1225 1226 - Helps developers verify that nothing is broken. 1227 1228 - Provides educational information to support the details 1229 of the hist trigger internals as described by 1230 Documentation/trace/histogram-design.rst. 1231 1232 The hist_debug output only covers the data structures 1233 related to the histogram definitions themselves and doesn't 1234 display the internals of map buckets or variable values of 1235 running histograms. 1236 1237 If unsure, say N. 1238 1239source "kernel/trace/rv/Kconfig" 1240 1241endif # FTRACE 1242