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