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