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