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 help 379 This tracer, when enabled will create one or more kernel threads, 380 depending on what the cpumask file is set to, which each thread 381 spinning in a loop looking for interruptions caused by 382 something other than the kernel. For example, if a 383 System Management Interrupt (SMI) takes a noticeable amount of 384 time, this tracer will detect it. This is useful for testing 385 if a system is reliable for Real Time tasks. 386 387 Some files are created in the tracing directory when this 388 is enabled: 389 390 hwlat_detector/width - time in usecs for how long to spin for 391 hwlat_detector/window - time in usecs between the start of each 392 iteration 393 394 A kernel thread is created that will spin with interrupts disabled 395 for "width" microseconds in every "window" cycle. It will not spin 396 for "window - width" microseconds, where the system can 397 continue to operate. 398 399 The output will appear in the trace and trace_pipe files. 400 401 When the tracer is not running, it has no affect on the system, 402 but when it is running, it can cause the system to be 403 periodically non responsive. Do not run this tracer on a 404 production system. 405 406 To enable this tracer, echo in "hwlat" into the current_tracer 407 file. Every time a latency is greater than tracing_thresh, it will 408 be recorded into the ring buffer. 409 410config OSNOISE_TRACER 411 bool "OS Noise tracer" 412 select GENERIC_TRACER 413 help 414 In the context of high-performance computing (HPC), the Operating 415 System Noise (osnoise) refers to the interference experienced by an 416 application due to activities inside the operating system. In the 417 context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread 418 can cause noise to the system. Moreover, hardware-related jobs can 419 also cause noise, for example, via SMIs. 420 421 The osnoise tracer leverages the hwlat_detector by running a similar 422 loop with preemption, SoftIRQs and IRQs enabled, thus allowing all 423 the sources of osnoise during its execution. The osnoise tracer takes 424 note of the entry and exit point of any source of interferences, 425 increasing a per-cpu interference counter. It saves an interference 426 counter for each source of interference. The interference counter for 427 NMI, IRQs, SoftIRQs, and threads is increased anytime the tool 428 observes these interferences' entry events. When a noise happens 429 without any interference from the operating system level, the 430 hardware noise counter increases, pointing to a hardware-related 431 noise. In this way, osnoise can account for any source of 432 interference. At the end of the period, the osnoise tracer prints 433 the sum of all noise, the max single noise, the percentage of CPU 434 available for the thread, and the counters for the noise sources. 435 436 In addition to the tracer, a set of tracepoints were added to 437 facilitate the identification of the osnoise source. 438 439 The output will appear in the trace and trace_pipe files. 440 441 To enable this tracer, echo in "osnoise" into the current_tracer 442 file. 443 444config TIMERLAT_TRACER 445 bool "Timerlat tracer" 446 select OSNOISE_TRACER 447 select GENERIC_TRACER 448 help 449 The timerlat tracer aims to help the preemptive kernel developers 450 to find sources of wakeup latencies of real-time threads. 451 452 The tracer creates a per-cpu kernel thread with real-time priority. 453 The tracer thread sets a periodic timer to wakeup itself, and goes 454 to sleep waiting for the timer to fire. At the wakeup, the thread 455 then computes a wakeup latency value as the difference between 456 the current time and the absolute time that the timer was set 457 to expire. 458 459 The tracer prints two lines at every activation. The first is the 460 timer latency observed at the hardirq context before the 461 activation of the thread. The second is the timer latency observed 462 by the thread, which is the same level that cyclictest reports. The 463 ACTIVATION ID field serves to relate the irq execution to its 464 respective thread execution. 465 466 The tracer is build on top of osnoise tracer, and the osnoise: 467 events can be used to trace the source of interference from NMI, 468 IRQs and other threads. It also enables the capture of the 469 stacktrace at the IRQ context, which helps to identify the code 470 path that can cause thread delay. 471 472config MMIOTRACE 473 bool "Memory mapped IO tracing" 474 depends on HAVE_MMIOTRACE_SUPPORT && PCI 475 select GENERIC_TRACER 476 help 477 Mmiotrace traces Memory Mapped I/O access and is meant for 478 debugging and reverse engineering. It is called from the ioremap 479 implementation and works via page faults. Tracing is disabled by 480 default and can be enabled at run-time. 481 482 See Documentation/trace/mmiotrace.rst. 483 If you are not helping to develop drivers, say N. 484 485config ENABLE_DEFAULT_TRACERS 486 bool "Trace process context switches and events" 487 depends on !GENERIC_TRACER 488 select TRACING 489 help 490 This tracer hooks to various trace points in the kernel, 491 allowing the user to pick and choose which trace point they 492 want to trace. It also includes the sched_switch tracer plugin. 493 494config FTRACE_SYSCALLS 495 bool "Trace syscalls" 496 depends on HAVE_SYSCALL_TRACEPOINTS 497 select GENERIC_TRACER 498 select KALLSYMS 499 help 500 Basic tracer to catch the syscall entry and exit events. 501 502config TRACER_SNAPSHOT 503 bool "Create a snapshot trace buffer" 504 select TRACER_MAX_TRACE 505 help 506 Allow tracing users to take snapshot of the current buffer using the 507 ftrace interface, e.g.: 508 509 echo 1 > /sys/kernel/debug/tracing/snapshot 510 cat snapshot 511 512config TRACER_SNAPSHOT_PER_CPU_SWAP 513 bool "Allow snapshot to swap per CPU" 514 depends on TRACER_SNAPSHOT 515 select RING_BUFFER_ALLOW_SWAP 516 help 517 Allow doing a snapshot of a single CPU buffer instead of a 518 full swap (all buffers). If this is set, then the following is 519 allowed: 520 521 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot 522 523 After which, only the tracing buffer for CPU 2 was swapped with 524 the main tracing buffer, and the other CPU buffers remain the same. 525 526 When this is enabled, this adds a little more overhead to the 527 trace recording, as it needs to add some checks to synchronize 528 recording with swaps. But this does not affect the performance 529 of the overall system. This is enabled by default when the preempt 530 or irq latency tracers are enabled, as those need to swap as well 531 and already adds the overhead (plus a lot more). 532 533config TRACE_BRANCH_PROFILING 534 bool 535 select GENERIC_TRACER 536 537choice 538 prompt "Branch Profiling" 539 default BRANCH_PROFILE_NONE 540 help 541 The branch profiling is a software profiler. It will add hooks 542 into the C conditionals to test which path a branch takes. 543 544 The likely/unlikely profiler only looks at the conditions that 545 are annotated with a likely or unlikely macro. 546 547 The "all branch" profiler will profile every if-statement in the 548 kernel. This profiler will also enable the likely/unlikely 549 profiler. 550 551 Either of the above profilers adds a bit of overhead to the system. 552 If unsure, choose "No branch profiling". 553 554config BRANCH_PROFILE_NONE 555 bool "No branch profiling" 556 help 557 No branch profiling. Branch profiling adds a bit of overhead. 558 Only enable it if you want to analyse the branching behavior. 559 Otherwise keep it disabled. 560 561config PROFILE_ANNOTATED_BRANCHES 562 bool "Trace likely/unlikely profiler" 563 select TRACE_BRANCH_PROFILING 564 help 565 This tracer profiles all likely and unlikely macros 566 in the kernel. It will display the results in: 567 568 /sys/kernel/debug/tracing/trace_stat/branch_annotated 569 570 Note: this will add a significant overhead; only turn this 571 on if you need to profile the system's use of these macros. 572 573config PROFILE_ALL_BRANCHES 574 bool "Profile all if conditionals" if !FORTIFY_SOURCE 575 select TRACE_BRANCH_PROFILING 576 help 577 This tracer profiles all branch conditions. Every if () 578 taken in the kernel is recorded whether it hit or miss. 579 The results will be displayed in: 580 581 /sys/kernel/debug/tracing/trace_stat/branch_all 582 583 This option also enables the likely/unlikely profiler. 584 585 This configuration, when enabled, will impose a great overhead 586 on the system. This should only be enabled when the system 587 is to be analyzed in much detail. 588endchoice 589 590config TRACING_BRANCHES 591 bool 592 help 593 Selected by tracers that will trace the likely and unlikely 594 conditions. This prevents the tracers themselves from being 595 profiled. Profiling the tracing infrastructure can only happen 596 when the likelys and unlikelys are not being traced. 597 598config BRANCH_TRACER 599 bool "Trace likely/unlikely instances" 600 depends on TRACE_BRANCH_PROFILING 601 select TRACING_BRANCHES 602 help 603 This traces the events of likely and unlikely condition 604 calls in the kernel. The difference between this and the 605 "Trace likely/unlikely profiler" is that this is not a 606 histogram of the callers, but actually places the calling 607 events into a running trace buffer to see when and where the 608 events happened, as well as their results. 609 610 Say N if unsure. 611 612config BLK_DEV_IO_TRACE 613 bool "Support for tracing block IO actions" 614 depends on SYSFS 615 depends on BLOCK 616 select RELAY 617 select DEBUG_FS 618 select TRACEPOINTS 619 select GENERIC_TRACER 620 select STACKTRACE 621 help 622 Say Y here if you want to be able to trace the block layer actions 623 on a given queue. Tracing allows you to see any traffic happening 624 on a block device queue. For more information (and the userspace 625 support tools needed), fetch the blktrace tools from: 626 627 git://git.kernel.dk/blktrace.git 628 629 Tracing also is possible using the ftrace interface, e.g.: 630 631 echo 1 > /sys/block/sda/sda1/trace/enable 632 echo blk > /sys/kernel/debug/tracing/current_tracer 633 cat /sys/kernel/debug/tracing/trace_pipe 634 635 If unsure, say N. 636 637config KPROBE_EVENTS 638 depends on KPROBES 639 depends on HAVE_REGS_AND_STACK_ACCESS_API 640 bool "Enable kprobes-based dynamic events" 641 select TRACING 642 select PROBE_EVENTS 643 select DYNAMIC_EVENTS 644 default y 645 help 646 This allows the user to add tracing events (similar to tracepoints) 647 on the fly via the ftrace interface. See 648 Documentation/trace/kprobetrace.rst for more details. 649 650 Those events can be inserted wherever kprobes can probe, and record 651 various register and memory values. 652 653 This option is also required by perf-probe subcommand of perf tools. 654 If you want to use perf tools, this option is strongly recommended. 655 656config KPROBE_EVENTS_ON_NOTRACE 657 bool "Do NOT protect notrace function from kprobe events" 658 depends on KPROBE_EVENTS 659 depends on DYNAMIC_FTRACE 660 default n 661 help 662 This is only for the developers who want to debug ftrace itself 663 using kprobe events. 664 665 If kprobes can use ftrace instead of breakpoint, ftrace related 666 functions are protected from kprobe-events to prevent an infinite 667 recursion or any unexpected execution path which leads to a kernel 668 crash. 669 670 This option disables such protection and allows you to put kprobe 671 events on ftrace functions for debugging ftrace by itself. 672 Note that this might let you shoot yourself in the foot. 673 674 If unsure, say N. 675 676config UPROBE_EVENTS 677 bool "Enable uprobes-based dynamic events" 678 depends on ARCH_SUPPORTS_UPROBES 679 depends on MMU 680 depends on PERF_EVENTS 681 select UPROBES 682 select PROBE_EVENTS 683 select DYNAMIC_EVENTS 684 select TRACING 685 default y 686 help 687 This allows the user to add tracing events on top of userspace 688 dynamic events (similar to tracepoints) on the fly via the trace 689 events interface. Those events can be inserted wherever uprobes 690 can probe, and record various registers. 691 This option is required if you plan to use perf-probe subcommand 692 of perf tools on user space applications. 693 694config BPF_EVENTS 695 depends on BPF_SYSCALL 696 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS 697 bool 698 default y 699 help 700 This allows the user to attach BPF programs to kprobe, uprobe, and 701 tracepoint events. 702 703config DYNAMIC_EVENTS 704 def_bool n 705 706config PROBE_EVENTS 707 def_bool n 708 709config BPF_KPROBE_OVERRIDE 710 bool "Enable BPF programs to override a kprobed function" 711 depends on BPF_EVENTS 712 depends on FUNCTION_ERROR_INJECTION 713 default n 714 help 715 Allows BPF to override the execution of a probed function and 716 set a different return value. This is used for error injection. 717 718config FTRACE_MCOUNT_RECORD 719 def_bool y 720 depends on DYNAMIC_FTRACE 721 depends on HAVE_FTRACE_MCOUNT_RECORD 722 723config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 724 bool 725 depends on FTRACE_MCOUNT_RECORD 726 727config FTRACE_MCOUNT_USE_CC 728 def_bool y 729 depends on $(cc-option,-mrecord-mcount) 730 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 731 depends on FTRACE_MCOUNT_RECORD 732 733config FTRACE_MCOUNT_USE_OBJTOOL 734 def_bool y 735 depends on HAVE_OBJTOOL_MCOUNT 736 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 737 depends on !FTRACE_MCOUNT_USE_CC 738 depends on FTRACE_MCOUNT_RECORD 739 select OBJTOOL 740 741config FTRACE_MCOUNT_USE_RECORDMCOUNT 742 def_bool y 743 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 744 depends on !FTRACE_MCOUNT_USE_CC 745 depends on !FTRACE_MCOUNT_USE_OBJTOOL 746 depends on FTRACE_MCOUNT_RECORD 747 748config TRACING_MAP 749 bool 750 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 751 help 752 tracing_map is a special-purpose lock-free map for tracing, 753 separated out as a stand-alone facility in order to allow it 754 to be shared between multiple tracers. It isn't meant to be 755 generally used outside of that context, and is normally 756 selected by tracers that use it. 757 758config SYNTH_EVENTS 759 bool "Synthetic trace events" 760 select TRACING 761 select DYNAMIC_EVENTS 762 default n 763 help 764 Synthetic events are user-defined trace events that can be 765 used to combine data from other trace events or in fact any 766 data source. Synthetic events can be generated indirectly 767 via the trace() action of histogram triggers or directly 768 by way of an in-kernel API. 769 770 See Documentation/trace/events.rst or 771 Documentation/trace/histogram.rst for details and examples. 772 773 If in doubt, say N. 774 775config USER_EVENTS 776 bool "User trace events" 777 select TRACING 778 select DYNAMIC_EVENTS 779 depends on BROKEN || COMPILE_TEST # API needs to be straighten out 780 help 781 User trace events are user-defined trace events that 782 can be used like an existing kernel trace event. User trace 783 events are generated by writing to a tracefs file. User 784 processes can determine if their tracing events should be 785 generated by memory mapping a tracefs file and checking for 786 an associated byte being non-zero. 787 788 If in doubt, say N. 789 790config HIST_TRIGGERS 791 bool "Histogram triggers" 792 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 793 select TRACING_MAP 794 select TRACING 795 select DYNAMIC_EVENTS 796 select SYNTH_EVENTS 797 default n 798 help 799 Hist triggers allow one or more arbitrary trace event fields 800 to be aggregated into hash tables and dumped to stdout by 801 reading a debugfs/tracefs file. They're useful for 802 gathering quick and dirty (though precise) summaries of 803 event activity as an initial guide for further investigation 804 using more advanced tools. 805 806 Inter-event tracing of quantities such as latencies is also 807 supported using hist triggers under this option. 808 809 See Documentation/trace/histogram.rst. 810 If in doubt, say N. 811 812config TRACE_EVENT_INJECT 813 bool "Trace event injection" 814 depends on TRACING 815 help 816 Allow user-space to inject a specific trace event into the ring 817 buffer. This is mainly used for testing purpose. 818 819 If unsure, say N. 820 821config TRACEPOINT_BENCHMARK 822 bool "Add tracepoint that benchmarks tracepoints" 823 help 824 This option creates the tracepoint "benchmark:benchmark_event". 825 When the tracepoint is enabled, it kicks off a kernel thread that 826 goes into an infinite loop (calling cond_resched() to let other tasks 827 run), and calls the tracepoint. Each iteration will record the time 828 it took to write to the tracepoint and the next iteration that 829 data will be passed to the tracepoint itself. That is, the tracepoint 830 will report the time it took to do the previous tracepoint. 831 The string written to the tracepoint is a static string of 128 bytes 832 to keep the time the same. The initial string is simply a write of 833 "START". The second string records the cold cache time of the first 834 write which is not added to the rest of the calculations. 835 836 As it is a tight loop, it benchmarks as hot cache. That's fine because 837 we care most about hot paths that are probably in cache already. 838 839 An example of the output: 840 841 START 842 first=3672 [COLD CACHED] 843 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712 844 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337 845 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064 846 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411 847 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389 848 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666 849 850 851config RING_BUFFER_BENCHMARK 852 tristate "Ring buffer benchmark stress tester" 853 depends on RING_BUFFER 854 help 855 This option creates a test to stress the ring buffer and benchmark it. 856 It creates its own ring buffer such that it will not interfere with 857 any other users of the ring buffer (such as ftrace). It then creates 858 a producer and consumer that will run for 10 seconds and sleep for 859 10 seconds. Each interval it will print out the number of events 860 it recorded and give a rough estimate of how long each iteration took. 861 862 It does not disable interrupts or raise its priority, so it may be 863 affected by processes that are running. 864 865 If unsure, say N. 866 867config TRACE_EVAL_MAP_FILE 868 bool "Show eval mappings for trace events" 869 depends on TRACING 870 help 871 The "print fmt" of the trace events will show the enum/sizeof names 872 instead of their values. This can cause problems for user space tools 873 that use this string to parse the raw data as user space does not know 874 how to convert the string to its value. 875 876 To fix this, there's a special macro in the kernel that can be used 877 to convert an enum/sizeof into its value. If this macro is used, then 878 the print fmt strings will be converted to their values. 879 880 If something does not get converted properly, this option can be 881 used to show what enums/sizeof the kernel tried to convert. 882 883 This option is for debugging the conversions. A file is created 884 in the tracing directory called "eval_map" that will show the 885 names matched with their values and what trace event system they 886 belong too. 887 888 Normally, the mapping of the strings to values will be freed after 889 boot up or module load. With this option, they will not be freed, as 890 they are needed for the "eval_map" file. Enabling this option will 891 increase the memory footprint of the running kernel. 892 893 If unsure, say N. 894 895config FTRACE_RECORD_RECURSION 896 bool "Record functions that recurse in function tracing" 897 depends on FUNCTION_TRACER 898 help 899 All callbacks that attach to the function tracing have some sort 900 of protection against recursion. Even though the protection exists, 901 it adds overhead. This option will create a file in the tracefs 902 file system called "recursed_functions" that will list the functions 903 that triggered a recursion. 904 905 This will add more overhead to cases that have recursion. 906 907 If unsure, say N 908 909config FTRACE_RECORD_RECURSION_SIZE 910 int "Max number of recursed functions to record" 911 default 128 912 depends on FTRACE_RECORD_RECURSION 913 help 914 This defines the limit of number of functions that can be 915 listed in the "recursed_functions" file, that lists all 916 the functions that caused a recursion to happen. 917 This file can be reset, but the limit can not change in 918 size at runtime. 919 920config RING_BUFFER_RECORD_RECURSION 921 bool "Record functions that recurse in the ring buffer" 922 depends on FTRACE_RECORD_RECURSION 923 # default y, because it is coupled with FTRACE_RECORD_RECURSION 924 default y 925 help 926 The ring buffer has its own internal recursion. Although when 927 recursion happens it wont cause harm because of the protection, 928 but it does cause an unwanted overhead. Enabling this option will 929 place where recursion was detected into the ftrace "recursed_functions" 930 file. 931 932 This will add more overhead to cases that have recursion. 933 934config GCOV_PROFILE_FTRACE 935 bool "Enable GCOV profiling on ftrace subsystem" 936 depends on GCOV_KERNEL 937 help 938 Enable GCOV profiling on ftrace subsystem for checking 939 which functions/lines are tested. 940 941 If unsure, say N. 942 943 Note that on a kernel compiled with this config, ftrace will 944 run significantly slower. 945 946config FTRACE_SELFTEST 947 bool 948 949config FTRACE_STARTUP_TEST 950 bool "Perform a startup test on ftrace" 951 depends on GENERIC_TRACER 952 select FTRACE_SELFTEST 953 help 954 This option performs a series of startup tests on ftrace. On bootup 955 a series of tests are made to verify that the tracer is 956 functioning properly. It will do tests on all the configured 957 tracers of ftrace. 958 959config EVENT_TRACE_STARTUP_TEST 960 bool "Run selftest on trace events" 961 depends on FTRACE_STARTUP_TEST 962 default y 963 help 964 This option performs a test on all trace events in the system. 965 It basically just enables each event and runs some code that 966 will trigger events (not necessarily the event it enables) 967 This may take some time run as there are a lot of events. 968 969config EVENT_TRACE_TEST_SYSCALLS 970 bool "Run selftest on syscall events" 971 depends on EVENT_TRACE_STARTUP_TEST 972 help 973 This option will also enable testing every syscall event. 974 It only enables the event and disables it and runs various loads 975 with the event enabled. This adds a bit more time for kernel boot 976 up since it runs this on every system call defined. 977 978 TBD - enable a way to actually call the syscalls as we test their 979 events 980 981config FTRACE_SORT_STARTUP_TEST 982 bool "Verify compile time sorting of ftrace functions" 983 depends on DYNAMIC_FTRACE 984 depends on BUILDTIME_MCOUNT_SORT 985 help 986 Sorting of the mcount_loc sections that is used to find the 987 where the ftrace knows where to patch functions for tracing 988 and other callbacks is done at compile time. But if the sort 989 is not done correctly, it will cause non-deterministic failures. 990 When this is set, the sorted sections will be verified that they 991 are in deed sorted and will warn if they are not. 992 993 If unsure, say N 994 995config RING_BUFFER_STARTUP_TEST 996 bool "Ring buffer startup self test" 997 depends on RING_BUFFER 998 help 999 Run a simple self test on the ring buffer on boot up. Late in the 1000 kernel boot sequence, the test will start that kicks off 1001 a thread per cpu. Each thread will write various size events 1002 into the ring buffer. Another thread is created to send IPIs 1003 to each of the threads, where the IPI handler will also write 1004 to the ring buffer, to test/stress the nesting ability. 1005 If any anomalies are discovered, a warning will be displayed 1006 and all ring buffers will be disabled. 1007 1008 The test runs for 10 seconds. This will slow your boot time 1009 by at least 10 more seconds. 1010 1011 At the end of the test, statics and more checks are done. 1012 It will output the stats of each per cpu buffer. What 1013 was written, the sizes, what was read, what was lost, and 1014 other similar details. 1015 1016 If unsure, say N 1017 1018config RING_BUFFER_VALIDATE_TIME_DELTAS 1019 bool "Verify ring buffer time stamp deltas" 1020 depends on RING_BUFFER 1021 help 1022 This will audit the time stamps on the ring buffer sub 1023 buffer to make sure that all the time deltas for the 1024 events on a sub buffer matches the current time stamp. 1025 This audit is performed for every event that is not 1026 interrupted, or interrupting another event. A check 1027 is also made when traversing sub buffers to make sure 1028 that all the deltas on the previous sub buffer do not 1029 add up to be greater than the current time stamp. 1030 1031 NOTE: This adds significant overhead to recording of events, 1032 and should only be used to test the logic of the ring buffer. 1033 Do not use it on production systems. 1034 1035 Only say Y if you understand what this does, and you 1036 still want it enabled. Otherwise say N 1037 1038config MMIOTRACE_TEST 1039 tristate "Test module for mmiotrace" 1040 depends on MMIOTRACE && m 1041 help 1042 This is a dumb module for testing mmiotrace. It is very dangerous 1043 as it will write garbage to IO memory starting at a given address. 1044 However, it should be safe to use on e.g. unused portion of VRAM. 1045 1046 Say N, unless you absolutely know what you are doing. 1047 1048config PREEMPTIRQ_DELAY_TEST 1049 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers" 1050 depends on m 1051 help 1052 Select this option to build a test module that can help test latency 1053 tracers by executing a preempt or irq disable section with a user 1054 configurable delay. The module busy waits for the duration of the 1055 critical section. 1056 1057 For example, the following invocation generates a burst of three 1058 irq-disabled critical sections for 500us: 1059 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3 1060 1061 What's more, if you want to attach the test on the cpu which the latency 1062 tracer is running on, specify cpu_affinity=cpu_num at the end of the 1063 command. 1064 1065 If unsure, say N 1066 1067config SYNTH_EVENT_GEN_TEST 1068 tristate "Test module for in-kernel synthetic event generation" 1069 depends on SYNTH_EVENTS 1070 help 1071 This option creates a test module to check the base 1072 functionality of in-kernel synthetic event definition and 1073 generation. 1074 1075 To test, insert the module, and then check the trace buffer 1076 for the generated sample events. 1077 1078 If unsure, say N. 1079 1080config KPROBE_EVENT_GEN_TEST 1081 tristate "Test module for in-kernel kprobe event generation" 1082 depends on KPROBE_EVENTS 1083 help 1084 This option creates a test module to check the base 1085 functionality of in-kernel kprobe event definition. 1086 1087 To test, insert the module, and then check the trace buffer 1088 for the generated kprobe events. 1089 1090 If unsure, say N. 1091 1092config HIST_TRIGGERS_DEBUG 1093 bool "Hist trigger debug support" 1094 depends on HIST_TRIGGERS 1095 help 1096 Add "hist_debug" file for each event, which when read will 1097 dump out a bunch of internal details about the hist triggers 1098 defined on that event. 1099 1100 The hist_debug file serves a couple of purposes: 1101 1102 - Helps developers verify that nothing is broken. 1103 1104 - Provides educational information to support the details 1105 of the hist trigger internals as described by 1106 Documentation/trace/histogram-design.rst. 1107 1108 The hist_debug output only covers the data structures 1109 related to the histogram definitions themselves and doesn't 1110 display the internals of map buckets or variable values of 1111 running histograms. 1112 1113 If unsure, say N. 1114 1115source "kernel/trace/rv/Kconfig" 1116 1117endif # FTRACE 1118
