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