1# SPDX-License-Identifier: GPL-2.0-only 2# 3# Architectures that offer an FUNCTION_TRACER implementation should 4# select HAVE_FUNCTION_TRACER: 5# 6 7config USER_STACKTRACE_SUPPORT 8 bool 9 10config NOP_TRACER 11 bool 12 13config HAVE_RETHOOK 14 bool 15 16config RETHOOK 17 bool 18 depends on HAVE_RETHOOK 19 help 20 Enable generic return hooking feature. This is an internal 21 API, which will be used by other function-entry hooking 22 features like fprobe and kprobes. 23 24config HAVE_FUNCTION_TRACER 25 bool 26 help 27 See Documentation/trace/ftrace-design.rst 28 29config HAVE_FUNCTION_GRAPH_TRACER 30 bool 31 help 32 See Documentation/trace/ftrace-design.rst 33 34config HAVE_FUNCTION_GRAPH_FREGS 35 bool 36 37config HAVE_FTRACE_GRAPH_FUNC 38 bool 39 help 40 True if ftrace_graph_func() is defined. 41 42config HAVE_DYNAMIC_FTRACE 43 bool 44 help 45 See Documentation/trace/ftrace-design.rst 46 47config HAVE_DYNAMIC_FTRACE_WITH_REGS 48 bool 49 50config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 51 bool 52 53config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 54 bool 55 56config HAVE_EXTRA_IPI_TRACEPOINTS 57 bool 58 help 59 For architectures that use ipi_raise, ipi_entry and ipi_exit 60 tracepoints. 61 62config HAVE_DYNAMIC_FTRACE_WITH_ARGS 63 bool 64 help 65 If this is set, then arguments and stack can be found from 66 the ftrace_regs passed into the function callback regs parameter 67 by default, even without setting the REGS flag in the ftrace_ops. 68 This allows for use of ftrace_regs_get_argument() and 69 ftrace_regs_get_stack_pointer(). 70 71config HAVE_FTRACE_REGS_HAVING_PT_REGS 72 bool 73 help 74 If this is set, ftrace_regs has pt_regs, thus it can convert to 75 pt_regs without allocating memory. 76 77config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE 78 bool 79 help 80 If the architecture generates __patchable_function_entries sections 81 but does not want them included in the ftrace locations. 82 83config HAVE_SYSCALL_TRACEPOINTS 84 bool 85 help 86 See Documentation/trace/ftrace-design.rst 87 88config HAVE_FENTRY 89 bool 90 help 91 Arch supports the gcc options -pg with -mfentry 92 93config HAVE_NOP_MCOUNT 94 bool 95 help 96 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount 97 98config HAVE_OBJTOOL_MCOUNT 99 bool 100 help 101 Arch supports objtool --mcount 102 103config HAVE_OBJTOOL_NOP_MCOUNT 104 bool 105 help 106 Arch supports the objtool options --mcount with --mnop. 107 An architecture can select this if it wants to enable nop'ing 108 of ftrace locations. 109 110config HAVE_C_RECORDMCOUNT 111 bool 112 help 113 C version of recordmcount available? 114 115config HAVE_BUILDTIME_MCOUNT_SORT 116 bool 117 help 118 An architecture selects this if it sorts the mcount_loc section 119 at build time. 120 121config BUILDTIME_MCOUNT_SORT 122 bool 123 default y 124 depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE 125 help 126 Sort the mcount_loc section at build time. 127 128config TRACER_MAX_TRACE 129 bool 130 131config TRACE_CLOCK 132 bool 133 134config RING_BUFFER 135 bool 136 select TRACE_CLOCK 137 select IRQ_WORK 138 139config EVENT_TRACING 140 select CONTEXT_SWITCH_TRACER 141 select GLOB 142 bool 143 144config CONTEXT_SWITCH_TRACER 145 bool 146 147config RING_BUFFER_ALLOW_SWAP 148 bool 149 help 150 Allow the use of ring_buffer_swap_cpu. 151 Adds a very slight overhead to tracing when enabled. 152 153config PREEMPTIRQ_TRACEPOINTS 154 bool 155 depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS 156 select TRACING 157 default y 158 help 159 Create preempt/irq toggle tracepoints if needed, so that other parts 160 of the kernel can use them to generate or add hooks to them. 161 162# All tracer options should select GENERIC_TRACER. For those options that are 163# enabled by all tracers (context switch and event tracer) they select TRACING. 164# This allows those options to appear when no other tracer is selected. But the 165# options do not appear when something else selects it. We need the two options 166# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the 167# hiding of the automatic options. 168 169config TRACING 170 bool 171 select RING_BUFFER 172 select STACKTRACE if STACKTRACE_SUPPORT 173 select TRACEPOINTS 174 select NOP_TRACER 175 select BINARY_PRINTF 176 select EVENT_TRACING 177 select TRACE_CLOCK 178 select NEED_TASKS_RCU 179 180config GENERIC_TRACER 181 bool 182 select TRACING 183 184# 185# Minimum requirements an architecture has to meet for us to 186# be able to offer generic tracing facilities: 187# 188config TRACING_SUPPORT 189 bool 190 depends on TRACE_IRQFLAGS_SUPPORT 191 depends on STACKTRACE_SUPPORT 192 default y 193 194menuconfig FTRACE 195 bool "Tracers" 196 depends on TRACING_SUPPORT 197 default y if DEBUG_KERNEL 198 help 199 Enable the kernel tracing infrastructure. 200 201if FTRACE 202 203config TRACEFS_AUTOMOUNT_DEPRECATED 204 bool "Automount tracefs on debugfs [DEPRECATED]" 205 depends on TRACING 206 default y 207 help 208 The tracing interface was moved from /sys/kernel/debug/tracing 209 to /sys/kernel/tracing in 2015, but the tracing file system 210 was still automounted in /sys/kernel/debug for backward 211 compatibility with tooling. 212 213 The new interface has been around for more than 10 years and 214 the old debug mount will soon be removed. 215 216config BOOTTIME_TRACING 217 bool "Boot-time Tracing support" 218 depends on TRACING 219 select BOOT_CONFIG 220 help 221 Enable developer to setup ftrace subsystem via supplemental 222 kernel cmdline at boot time for debugging (tracing) driver 223 initialization and boot process. 224 225config FUNCTION_TRACER 226 bool "Kernel Function Tracer" 227 depends on HAVE_FUNCTION_TRACER 228 select KALLSYMS 229 select GENERIC_TRACER 230 select CONTEXT_SWITCH_TRACER 231 select GLOB 232 select NEED_TASKS_RCU 233 select TASKS_RUDE_RCU 234 help 235 Enable the kernel to trace every kernel function. This is done 236 by using a compiler feature to insert a small, 5-byte No-Operation 237 instruction at the beginning of every kernel function, which NOP 238 sequence is then dynamically patched into a tracer call when 239 tracing is enabled by the administrator. If it's runtime disabled 240 (the bootup default), then the overhead of the instructions is very 241 small and not measurable even in micro-benchmarks (at least on 242 x86, but may have impact on other architectures). 243 244config FUNCTION_GRAPH_TRACER 245 bool "Kernel Function Graph Tracer" 246 depends on HAVE_FUNCTION_GRAPH_TRACER 247 depends on FUNCTION_TRACER 248 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE 249 default y 250 help 251 Enable the kernel to trace a function at both its return 252 and its entry. 253 Its first purpose is to trace the duration of functions and 254 draw a call graph for each thread with some information like 255 the return value. This is done by setting the current return 256 address on the current task structure into a stack of calls. 257 258config FUNCTION_GRAPH_RETVAL 259 bool "Kernel Function Graph Return Value" 260 depends on HAVE_FUNCTION_GRAPH_FREGS 261 depends on FUNCTION_GRAPH_TRACER 262 default n 263 help 264 Support recording and printing the function return value when 265 using function graph tracer. It can be helpful to locate functions 266 that return errors. This feature is off by default, and you can 267 enable it via the trace option funcgraph-retval. 268 See Documentation/trace/ftrace.rst 269 270config FUNCTION_GRAPH_RETADDR 271 bool "Kernel Function Graph Return Address" 272 depends on FUNCTION_GRAPH_TRACER 273 default n 274 help 275 Support recording and printing the function return address when 276 using function graph tracer. It can be helpful to locate code line that 277 the function is called. This feature is off by default, and you can 278 enable it via the trace option funcgraph-retaddr. 279 280config FUNCTION_TRACE_ARGS 281 bool 282 depends on PROBE_EVENTS_BTF_ARGS 283 default y 284 help 285 If supported with function argument access API and BTF, then 286 the function tracer and function graph tracer will support printing 287 of function arguments. This feature is off by default, and can be 288 enabled via the trace option func-args (for the function tracer) and 289 funcgraph-args (for the function graph tracer) 290 291config DYNAMIC_FTRACE 292 bool 293 depends on FUNCTION_TRACER 294 depends on HAVE_DYNAMIC_FTRACE 295 default y 296 help 297 This option will modify all the calls to function tracing 298 dynamically (will patch them out of the binary image and 299 replace them with a No-Op instruction) on boot up. During 300 compile time, a table is made of all the locations that ftrace 301 can function trace, and this table is linked into the kernel 302 image. When this is enabled, functions can be individually 303 enabled, and the functions not enabled will not affect 304 performance of the system. 305 306 See the files in /sys/kernel/tracing: 307 available_filter_functions 308 set_ftrace_filter 309 set_ftrace_notrace 310 311 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 312 otherwise has native performance as long as no tracing is active. 313 314config DYNAMIC_FTRACE_WITH_REGS 315 def_bool y 316 depends on DYNAMIC_FTRACE 317 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS 318 319config DYNAMIC_FTRACE_WITH_DIRECT_CALLS 320 def_bool y 321 depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS 322 depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 323 324config DYNAMIC_FTRACE_WITH_CALL_OPS 325 def_bool y 326 depends on HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS 327 328config DYNAMIC_FTRACE_WITH_ARGS 329 def_bool y 330 depends on DYNAMIC_FTRACE 331 depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS 332 333config FPROBE 334 bool "Kernel Function Probe (fprobe)" 335 depends on HAVE_FUNCTION_GRAPH_FREGS && HAVE_FTRACE_GRAPH_FUNC 336 depends on DYNAMIC_FTRACE_WITH_ARGS 337 select FUNCTION_GRAPH_TRACER 338 default n 339 help 340 This option enables kernel function probe (fprobe) based on ftrace. 341 The fprobe is similar to kprobes, but probes only for kernel function 342 entries and exits. This also can probe multiple functions by one 343 fprobe. 344 345 If unsure, say N. 346 347config FUNCTION_PROFILER 348 bool "Kernel function profiler" 349 depends on FUNCTION_TRACER 350 default n 351 help 352 This option enables the kernel function profiler. A file is created 353 in debugfs called function_profile_enabled which defaults to zero. 354 When a 1 is echoed into this file profiling begins, and when a 355 zero is entered, profiling stops. A "functions" file is created in 356 the trace_stat directory; this file shows the list of functions that 357 have been hit and their counters. 358 359 If in doubt, say N. 360 361config STACK_TRACER 362 bool "Trace max stack" 363 depends on HAVE_FUNCTION_TRACER 364 select FUNCTION_TRACER 365 select STACKTRACE 366 select KALLSYMS 367 help 368 This special tracer records the maximum stack footprint of the 369 kernel and displays it in /sys/kernel/tracing/stack_trace. 370 371 This tracer works by hooking into every function call that the 372 kernel executes, and keeping a maximum stack depth value and 373 stack-trace saved. If this is configured with DYNAMIC_FTRACE 374 then it will not have any overhead while the stack tracer 375 is disabled. 376 377 To enable the stack tracer on bootup, pass in 'stacktrace' 378 on the kernel command line. 379 380 The stack tracer can also be enabled or disabled via the 381 sysctl kernel.stack_tracer_enabled 382 383 Say N if unsure. 384 385config TRACE_PREEMPT_TOGGLE 386 bool 387 help 388 Enables hooks which will be called when preemption is first disabled, 389 and last enabled. 390 391config IRQSOFF_TRACER 392 bool "Interrupts-off Latency Tracer" 393 default n 394 depends on TRACE_IRQFLAGS_SUPPORT 395 select TRACE_IRQFLAGS 396 select GENERIC_TRACER 397 select TRACER_MAX_TRACE 398 select RING_BUFFER_ALLOW_SWAP 399 select TRACER_SNAPSHOT 400 select TRACER_SNAPSHOT_PER_CPU_SWAP 401 help 402 This option measures the time spent in irqs-off critical 403 sections, with microsecond accuracy. 404 405 The default measurement method is a maximum search, which is 406 disabled by default and can be runtime (re-)started 407 via: 408 409 echo 0 > /sys/kernel/tracing/tracing_max_latency 410 411 (Note that kernel size and overhead increase with this option 412 enabled. This option and the preempt-off timing option can be 413 used together or separately.) 414 415config PREEMPT_TRACER 416 bool "Preemption-off Latency Tracer" 417 default n 418 depends on PREEMPTION 419 select GENERIC_TRACER 420 select TRACER_MAX_TRACE 421 select RING_BUFFER_ALLOW_SWAP 422 select TRACER_SNAPSHOT 423 select TRACER_SNAPSHOT_PER_CPU_SWAP 424 select TRACE_PREEMPT_TOGGLE 425 help 426 This option measures the time spent in preemption-off critical 427 sections, with microsecond accuracy. 428 429 The default measurement method is a maximum search, which is 430 disabled by default and can be runtime (re-)started 431 via: 432 433 echo 0 > /sys/kernel/tracing/tracing_max_latency 434 435 (Note that kernel size and overhead increase with this option 436 enabled. This option and the irqs-off timing option can be 437 used together or separately.) 438 439config SCHED_TRACER 440 bool "Scheduling Latency Tracer" 441 select GENERIC_TRACER 442 select CONTEXT_SWITCH_TRACER 443 select TRACER_MAX_TRACE 444 select TRACER_SNAPSHOT 445 help 446 This tracer tracks the latency of the highest priority task 447 to be scheduled in, starting from the point it has woken up. 448 449config HWLAT_TRACER 450 bool "Tracer to detect hardware latencies (like SMIs)" 451 select GENERIC_TRACER 452 select TRACER_MAX_TRACE 453 help 454 This tracer, when enabled will create one or more kernel threads, 455 depending on what the cpumask file is set to, which each thread 456 spinning in a loop looking for interruptions caused by 457 something other than the kernel. For example, if a 458 System Management Interrupt (SMI) takes a noticeable amount of 459 time, this tracer will detect it. This is useful for testing 460 if a system is reliable for Real Time tasks. 461 462 Some files are created in the tracing directory when this 463 is enabled: 464 465 hwlat_detector/width - time in usecs for how long to spin for 466 hwlat_detector/window - time in usecs between the start of each 467 iteration 468 469 A kernel thread is created that will spin with interrupts disabled 470 for "width" microseconds in every "window" cycle. It will not spin 471 for "window - width" microseconds, where the system can 472 continue to operate. 473 474 The output will appear in the trace and trace_pipe files. 475 476 When the tracer is not running, it has no affect on the system, 477 but when it is running, it can cause the system to be 478 periodically non responsive. Do not run this tracer on a 479 production system. 480 481 To enable this tracer, echo in "hwlat" into the current_tracer 482 file. Every time a latency is greater than tracing_thresh, it will 483 be recorded into the ring buffer. 484 485config OSNOISE_TRACER 486 bool "OS Noise tracer" 487 select GENERIC_TRACER 488 select TRACER_MAX_TRACE 489 help 490 In the context of high-performance computing (HPC), the Operating 491 System Noise (osnoise) refers to the interference experienced by an 492 application due to activities inside the operating system. In the 493 context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread 494 can cause noise to the system. Moreover, hardware-related jobs can 495 also cause noise, for example, via SMIs. 496 497 The osnoise tracer leverages the hwlat_detector by running a similar 498 loop with preemption, SoftIRQs and IRQs enabled, thus allowing all 499 the sources of osnoise during its execution. The osnoise tracer takes 500 note of the entry and exit point of any source of interferences, 501 increasing a per-cpu interference counter. It saves an interference 502 counter for each source of interference. The interference counter for 503 NMI, IRQs, SoftIRQs, and threads is increased anytime the tool 504 observes these interferences' entry events. When a noise happens 505 without any interference from the operating system level, the 506 hardware noise counter increases, pointing to a hardware-related 507 noise. In this way, osnoise can account for any source of 508 interference. At the end of the period, the osnoise tracer prints 509 the sum of all noise, the max single noise, the percentage of CPU 510 available for the thread, and the counters for the noise sources. 511 512 In addition to the tracer, a set of tracepoints were added to 513 facilitate the identification of the osnoise source. 514 515 The output will appear in the trace and trace_pipe files. 516 517 To enable this tracer, echo in "osnoise" into the current_tracer 518 file. 519 520config TIMERLAT_TRACER 521 bool "Timerlat tracer" 522 select OSNOISE_TRACER 523 select GENERIC_TRACER 524 help 525 The timerlat tracer aims to help the preemptive kernel developers 526 to find sources of wakeup latencies of real-time threads. 527 528 The tracer creates a per-cpu kernel thread with real-time priority. 529 The tracer thread sets a periodic timer to wakeup itself, and goes 530 to sleep waiting for the timer to fire. At the wakeup, the thread 531 then computes a wakeup latency value as the difference between 532 the current time and the absolute time that the timer was set 533 to expire. 534 535 The tracer prints two lines at every activation. The first is the 536 timer latency observed at the hardirq context before the 537 activation of the thread. The second is the timer latency observed 538 by the thread, which is the same level that cyclictest reports. The 539 ACTIVATION ID field serves to relate the irq execution to its 540 respective thread execution. 541 542 The tracer is build on top of osnoise tracer, and the osnoise: 543 events can be used to trace the source of interference from NMI, 544 IRQs and other threads. It also enables the capture of the 545 stacktrace at the IRQ context, which helps to identify the code 546 path that can cause thread delay. 547 548config MMIOTRACE 549 bool "Memory mapped IO tracing" 550 depends on HAVE_MMIOTRACE_SUPPORT && PCI 551 select GENERIC_TRACER 552 help 553 Mmiotrace traces Memory Mapped I/O access and is meant for 554 debugging and reverse engineering. It is called from the ioremap 555 implementation and works via page faults. Tracing is disabled by 556 default and can be enabled at run-time. 557 558 See Documentation/trace/mmiotrace.rst. 559 If you are not helping to develop drivers, say N. 560 561config ENABLE_DEFAULT_TRACERS 562 bool "Trace process context switches and events" 563 depends on !GENERIC_TRACER 564 select TRACING 565 help 566 This tracer hooks to various trace points in the kernel, 567 allowing the user to pick and choose which trace point they 568 want to trace. It also includes the sched_switch tracer plugin. 569 570config FTRACE_SYSCALLS 571 bool "Trace syscalls" 572 depends on HAVE_SYSCALL_TRACEPOINTS 573 select GENERIC_TRACER 574 select KALLSYMS 575 help 576 Basic tracer to catch the syscall entry and exit events. 577 578config TRACE_SYSCALL_BUF_SIZE_DEFAULT 579 int "System call user read max size" 580 range 0 165 581 default 63 582 depends on FTRACE_SYSCALLS 583 help 584 Some system call trace events will record the data from a user 585 space address that one of the parameters point to. The amount of 586 data per event is limited. That limit is set by this config and 587 this config also affects how much user space data perf can read. 588 589 For a tracing instance, this size may be changed by writing into 590 its syscall_user_buf_size file. 591 592config TRACER_SNAPSHOT 593 bool "Create a snapshot trace buffer" 594 select TRACER_MAX_TRACE 595 help 596 Allow tracing users to take snapshot of the current buffer using the 597 ftrace interface, e.g.: 598 599 echo 1 > /sys/kernel/tracing/snapshot 600 cat snapshot 601 602config TRACER_SNAPSHOT_PER_CPU_SWAP 603 bool "Allow snapshot to swap per CPU" 604 depends on TRACER_SNAPSHOT 605 select RING_BUFFER_ALLOW_SWAP 606 help 607 Allow doing a snapshot of a single CPU buffer instead of a 608 full swap (all buffers). If this is set, then the following is 609 allowed: 610 611 echo 1 > /sys/kernel/tracing/per_cpu/cpu2/snapshot 612 613 After which, only the tracing buffer for CPU 2 was swapped with 614 the main tracing buffer, and the other CPU buffers remain the same. 615 616 When this is enabled, this adds a little more overhead to the 617 trace recording, as it needs to add some checks to synchronize 618 recording with swaps. But this does not affect the performance 619 of the overall system. This is enabled by default when the preempt 620 or irq latency tracers are enabled, as those need to swap as well 621 and already adds the overhead (plus a lot more). 622 623config TRACE_BRANCH_PROFILING 624 bool 625 select GENERIC_TRACER 626 627choice 628 prompt "Branch Profiling" 629 default BRANCH_PROFILE_NONE 630 help 631 The branch profiling is a software profiler. It will add hooks 632 into the C conditionals to test which path a branch takes. 633 634 The likely/unlikely profiler only looks at the conditions that 635 are annotated with a likely or unlikely macro. 636 637 The "all branch" profiler will profile every if-statement in the 638 kernel. This profiler will also enable the likely/unlikely 639 profiler. 640 641 Either of the above profilers adds a bit of overhead to the system. 642 If unsure, choose "No branch profiling". 643 644config BRANCH_PROFILE_NONE 645 bool "No branch profiling" 646 help 647 No branch profiling. Branch profiling adds a bit of overhead. 648 Only enable it if you want to analyse the branching behavior. 649 Otherwise keep it disabled. 650 651config PROFILE_ANNOTATED_BRANCHES 652 bool "Trace likely/unlikely profiler" 653 select TRACE_BRANCH_PROFILING 654 help 655 This tracer profiles all likely and unlikely macros 656 in the kernel. It will display the results in: 657 658 /sys/kernel/tracing/trace_stat/branch_annotated 659 660 Note: this will add a significant overhead; only turn this 661 on if you need to profile the system's use of these macros. 662 663config PROFILE_ALL_BRANCHES 664 bool "Profile all if conditionals" if !FORTIFY_SOURCE 665 select TRACE_BRANCH_PROFILING 666 help 667 This tracer profiles all branch conditions. Every if () 668 taken in the kernel is recorded whether it hit or miss. 669 The results will be displayed in: 670 671 /sys/kernel/tracing/trace_stat/branch_all 672 673 This option also enables the likely/unlikely profiler. 674 675 This configuration, when enabled, will impose a great overhead 676 on the system. This should only be enabled when the system 677 is to be analyzed in much detail. 678endchoice 679 680config TRACING_BRANCHES 681 bool 682 help 683 Selected by tracers that will trace the likely and unlikely 684 conditions. This prevents the tracers themselves from being 685 profiled. Profiling the tracing infrastructure can only happen 686 when the likelys and unlikelys are not being traced. 687 688config BRANCH_TRACER 689 bool "Trace likely/unlikely instances" 690 depends on TRACE_BRANCH_PROFILING 691 select TRACING_BRANCHES 692 help 693 This traces the events of likely and unlikely condition 694 calls in the kernel. The difference between this and the 695 "Trace likely/unlikely profiler" is that this is not a 696 histogram of the callers, but actually places the calling 697 events into a running trace buffer to see when and where the 698 events happened, as well as their results. 699 700 Say N if unsure. 701 702config BLK_DEV_IO_TRACE 703 bool "Support for tracing block IO actions" 704 depends on SYSFS 705 depends on BLOCK 706 select RELAY 707 select DEBUG_FS 708 select TRACEPOINTS 709 select GENERIC_TRACER 710 select STACKTRACE 711 help 712 Say Y here if you want to be able to trace the block layer actions 713 on a given queue. Tracing allows you to see any traffic happening 714 on a block device queue. For more information (and the userspace 715 support tools needed), fetch the blktrace tools from: 716 717 git://git.kernel.dk/blktrace.git 718 719 Tracing also is possible using the ftrace interface, e.g.: 720 721 echo 1 > /sys/block/sda/sda1/trace/enable 722 echo blk > /sys/kernel/tracing/current_tracer 723 cat /sys/kernel/tracing/trace_pipe 724 725 If unsure, say N. 726 727config FPROBE_EVENTS 728 depends on FPROBE 729 depends on HAVE_REGS_AND_STACK_ACCESS_API 730 bool "Enable fprobe-based dynamic events" 731 select TRACING 732 select PROBE_EVENTS 733 select DYNAMIC_EVENTS 734 default y 735 help 736 This allows user to add tracing events on the function entry and 737 exit via ftrace interface. The syntax is same as the kprobe events 738 and the kprobe events on function entry and exit will be 739 transparently converted to this fprobe events. 740 741config PROBE_EVENTS_BTF_ARGS 742 depends on HAVE_FUNCTION_ARG_ACCESS_API 743 depends on FPROBE_EVENTS || KPROBE_EVENTS 744 depends on DEBUG_INFO_BTF && BPF_SYSCALL 745 bool "Support BTF function arguments for probe events" 746 default y 747 help 748 The user can specify the arguments of the probe event using the names 749 of the arguments of the probed function, when the probe location is a 750 kernel function entry or a tracepoint. 751 This is available only if BTF (BPF Type Format) support is enabled. 752 753config KPROBE_EVENTS 754 depends on KPROBES 755 depends on HAVE_REGS_AND_STACK_ACCESS_API 756 bool "Enable kprobes-based dynamic events" 757 select TRACING 758 select PROBE_EVENTS 759 select DYNAMIC_EVENTS 760 default y 761 help 762 This allows the user to add tracing events (similar to tracepoints) 763 on the fly via the ftrace interface. See 764 Documentation/trace/kprobetrace.rst for more details. 765 766 Those events can be inserted wherever kprobes can probe, and record 767 various register and memory values. 768 769 This option is also required by perf-probe subcommand of perf tools. 770 If you want to use perf tools, this option is strongly recommended. 771 772config KPROBE_EVENTS_ON_NOTRACE 773 bool "Do NOT protect notrace function from kprobe events" 774 depends on KPROBE_EVENTS 775 depends on DYNAMIC_FTRACE 776 default n 777 help 778 This is only for the developers who want to debug ftrace itself 779 using kprobe events. 780 781 If kprobes can use ftrace instead of breakpoint, ftrace related 782 functions are protected from kprobe-events to prevent an infinite 783 recursion or any unexpected execution path which leads to a kernel 784 crash. 785 786 This option disables such protection and allows you to put kprobe 787 events on ftrace functions for debugging ftrace by itself. 788 Note that this might let you shoot yourself in the foot. 789 790 If unsure, say N. 791 792config UPROBE_EVENTS 793 bool "Enable uprobes-based dynamic events" 794 depends on ARCH_SUPPORTS_UPROBES 795 depends on MMU 796 depends on PERF_EVENTS 797 select UPROBES 798 select PROBE_EVENTS 799 select DYNAMIC_EVENTS 800 select TRACING 801 default y 802 help 803 This allows the user to add tracing events on top of userspace 804 dynamic events (similar to tracepoints) on the fly via the trace 805 events interface. Those events can be inserted wherever uprobes 806 can probe, and record various registers. 807 This option is required if you plan to use perf-probe subcommand 808 of perf tools on user space applications. 809 810config EPROBE_EVENTS 811 bool "Enable event-based dynamic events" 812 depends on TRACING 813 depends on HAVE_REGS_AND_STACK_ACCESS_API 814 select PROBE_EVENTS 815 select DYNAMIC_EVENTS 816 default y 817 help 818 Eprobes are dynamic events that can be placed on other existing 819 events. It can be used to limit what fields are recorded in 820 an event or even dereference a field of an event. It can 821 convert the type of an event field. For example, turn an 822 address into a string. 823 824config BPF_EVENTS 825 depends on BPF_SYSCALL 826 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS 827 bool 828 default y 829 help 830 This allows the user to attach BPF programs to kprobe, uprobe, and 831 tracepoint events. 832 833config DYNAMIC_EVENTS 834 def_bool n 835 836config PROBE_EVENTS 837 def_bool n 838 839config BPF_KPROBE_OVERRIDE 840 bool "Enable BPF programs to override a kprobed function" 841 depends on BPF_EVENTS 842 depends on FUNCTION_ERROR_INJECTION 843 default n 844 help 845 Allows BPF to override the execution of a probed function and 846 set a different return value. This is used for error injection. 847 848config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 849 bool 850 depends on DYNAMIC_FTRACE 851 852config FTRACE_MCOUNT_USE_CC 853 def_bool y 854 depends on $(cc-option,-mrecord-mcount) 855 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 856 depends on DYNAMIC_FTRACE 857 858config FTRACE_MCOUNT_USE_OBJTOOL 859 def_bool y 860 depends on HAVE_OBJTOOL_MCOUNT 861 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 862 depends on !FTRACE_MCOUNT_USE_CC 863 depends on DYNAMIC_FTRACE 864 select OBJTOOL 865 866config FTRACE_MCOUNT_USE_RECORDMCOUNT 867 def_bool y 868 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY 869 depends on !FTRACE_MCOUNT_USE_CC 870 depends on !FTRACE_MCOUNT_USE_OBJTOOL 871 depends on DYNAMIC_FTRACE 872 873config TRACING_MAP 874 bool 875 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 876 help 877 tracing_map is a special-purpose lock-free map for tracing, 878 separated out as a stand-alone facility in order to allow it 879 to be shared between multiple tracers. It isn't meant to be 880 generally used outside of that context, and is normally 881 selected by tracers that use it. 882 883config SYNTH_EVENTS 884 bool "Synthetic trace events" 885 select TRACING 886 select DYNAMIC_EVENTS 887 default n 888 help 889 Synthetic events are user-defined trace events that can be 890 used to combine data from other trace events or in fact any 891 data source. Synthetic events can be generated indirectly 892 via the trace() action of histogram triggers or directly 893 by way of an in-kernel API. 894 895 See Documentation/trace/events.rst or 896 Documentation/trace/histogram.rst for details and examples. 897 898 If in doubt, say N. 899 900config USER_EVENTS 901 bool "User trace events" 902 select TRACING 903 select DYNAMIC_EVENTS 904 help 905 User trace events are user-defined trace events that 906 can be used like an existing kernel trace event. User trace 907 events are generated by writing to a tracefs file. User 908 processes can determine if their tracing events should be 909 generated by registering a value and bit with the kernel 910 that reflects when it is enabled or not. 911 912 See Documentation/trace/user_events.rst. 913 If in doubt, say N. 914 915config HIST_TRIGGERS 916 bool "Histogram triggers" 917 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 918 select TRACING_MAP 919 select TRACING 920 select DYNAMIC_EVENTS 921 select SYNTH_EVENTS 922 default n 923 help 924 Hist triggers allow one or more arbitrary trace event fields 925 to be aggregated into hash tables and dumped to stdout by 926 reading a debugfs/tracefs file. They're useful for 927 gathering quick and dirty (though precise) summaries of 928 event activity as an initial guide for further investigation 929 using more advanced tools. 930 931 Inter-event tracing of quantities such as latencies is also 932 supported using hist triggers under this option. 933 934 See Documentation/trace/histogram.rst. 935 If in doubt, say N. 936 937config TRACE_EVENT_INJECT 938 bool "Trace event injection" 939 depends on TRACING 940 help 941 Allow user-space to inject a specific trace event into the ring 942 buffer. This is mainly used for testing purpose. 943 944 If unsure, say N. 945 946config TRACEPOINT_BENCHMARK 947 bool "Add tracepoint that benchmarks tracepoints" 948 help 949 This option creates the tracepoint "benchmark:benchmark_event". 950 When the tracepoint is enabled, it kicks off a kernel thread that 951 goes into an infinite loop (calling cond_resched() to let other tasks 952 run), and calls the tracepoint. Each iteration will record the time 953 it took to write to the tracepoint and the next iteration that 954 data will be passed to the tracepoint itself. That is, the tracepoint 955 will report the time it took to do the previous tracepoint. 956 The string written to the tracepoint is a static string of 128 bytes 957 to keep the time the same. The initial string is simply a write of 958 "START". The second string records the cold cache time of the first 959 write which is not added to the rest of the calculations. 960 961 As it is a tight loop, it benchmarks as hot cache. That's fine because 962 we care most about hot paths that are probably in cache already. 963 964 An example of the output: 965 966 START 967 first=3672 [COLD CACHED] 968 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712 969 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337 970 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064 971 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411 972 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389 973 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666 974 975 976config RING_BUFFER_BENCHMARK 977 tristate "Ring buffer benchmark stress tester" 978 depends on RING_BUFFER 979 help 980 This option creates a test to stress the ring buffer and benchmark it. 981 It creates its own ring buffer such that it will not interfere with 982 any other users of the ring buffer (such as ftrace). It then creates 983 a producer and consumer that will run for 10 seconds and sleep for 984 10 seconds. Each interval it will print out the number of events 985 it recorded and give a rough estimate of how long each iteration took. 986 987 It does not disable interrupts or raise its priority, so it may be 988 affected by processes that are running. 989 990 If unsure, say N. 991 992config TRACE_EVAL_MAP_FILE 993 bool "Show eval mappings for trace events" 994 depends on TRACING 995 help 996 The "print fmt" of the trace events will show the enum/sizeof names 997 instead of their values. This can cause problems for user space tools 998 that use this string to parse the raw data as user space does not know 999 how to convert the string to its value. 1000 1001 To fix this, there's a special macro in the kernel that can be used 1002 to convert an enum/sizeof into its value. If this macro is used, then 1003 the print fmt strings will be converted to their values. 1004 1005 If something does not get converted properly, this option can be 1006 used to show what enums/sizeof the kernel tried to convert. 1007 1008 This option is for debugging the conversions. A file is created 1009 in the tracing directory called "eval_map" that will show the 1010 names matched with their values and what trace event system they 1011 belong too. 1012 1013 Normally, the mapping of the strings to values will be freed after 1014 boot up or module load. With this option, they will not be freed, as 1015 they are needed for the "eval_map" file. Enabling this option will 1016 increase the memory footprint of the running kernel. 1017 1018 If unsure, say N. 1019 1020config FTRACE_RECORD_RECURSION 1021 bool "Record functions that recurse in function tracing" 1022 depends on FUNCTION_TRACER 1023 help 1024 All callbacks that attach to the function tracing have some sort 1025 of protection against recursion. Even though the protection exists, 1026 it adds overhead. This option will create a file in the tracefs 1027 file system called "recursed_functions" that will list the functions 1028 that triggered a recursion. 1029 1030 This will add more overhead to cases that have recursion. 1031 1032 If unsure, say N 1033 1034config FTRACE_RECORD_RECURSION_SIZE 1035 int "Max number of recursed functions to record" 1036 default 128 1037 depends on FTRACE_RECORD_RECURSION 1038 help 1039 This defines the limit of number of functions that can be 1040 listed in the "recursed_functions" file, that lists all 1041 the functions that caused a recursion to happen. 1042 This file can be reset, but the limit can not change in 1043 size at runtime. 1044 1045config FTRACE_VALIDATE_RCU_IS_WATCHING 1046 bool "Validate RCU is on during ftrace execution" 1047 depends on FUNCTION_TRACER 1048 depends on ARCH_WANTS_NO_INSTR 1049 help 1050 All callbacks that attach to the function tracing have some sort of 1051 protection against recursion. This option is only to verify that 1052 ftrace (and other users of ftrace_test_recursion_trylock()) are not 1053 called outside of RCU, as if they are, it can cause a race. But it 1054 also has a noticeable overhead when enabled. 1055 1056 If unsure, say N 1057 1058config RING_BUFFER_RECORD_RECURSION 1059 bool "Record functions that recurse in the ring buffer" 1060 depends on FTRACE_RECORD_RECURSION 1061 # default y, because it is coupled with FTRACE_RECORD_RECURSION 1062 default y 1063 help 1064 The ring buffer has its own internal recursion. Although when 1065 recursion happens it won't cause harm because of the protection, 1066 but it does cause unwanted overhead. Enabling this option will 1067 place where recursion was detected into the ftrace "recursed_functions" 1068 file. 1069 1070 This will add more overhead to cases that have recursion. 1071 1072config GCOV_PROFILE_FTRACE 1073 bool "Enable GCOV profiling on ftrace subsystem" 1074 depends on GCOV_KERNEL 1075 help 1076 Enable GCOV profiling on ftrace subsystem for checking 1077 which functions/lines are tested. 1078 1079 If unsure, say N. 1080 1081 Note that on a kernel compiled with this config, ftrace will 1082 run significantly slower. 1083 1084config FTRACE_SELFTEST 1085 bool 1086 1087config FTRACE_STARTUP_TEST 1088 bool "Perform a startup test on ftrace" 1089 depends on GENERIC_TRACER 1090 select FTRACE_SELFTEST 1091 help 1092 This option performs a series of startup tests on ftrace. On bootup 1093 a series of tests are made to verify that the tracer is 1094 functioning properly. It will do tests on all the configured 1095 tracers of ftrace. 1096 1097config EVENT_TRACE_STARTUP_TEST 1098 bool "Run selftest on trace events" 1099 depends on FTRACE_STARTUP_TEST 1100 default y 1101 help 1102 This option performs a test on all trace events in the system. 1103 It basically just enables each event and runs some code that 1104 will trigger events (not necessarily the event it enables) 1105 This may take some time run as there are a lot of events. 1106 1107config EVENT_TRACE_TEST_SYSCALLS 1108 bool "Run selftest on syscall events" 1109 depends on EVENT_TRACE_STARTUP_TEST 1110 help 1111 This option will also enable testing every syscall event. 1112 It only enables the event and disables it and runs various loads 1113 with the event enabled. This adds a bit more time for kernel boot 1114 up since it runs this on every system call defined. 1115 1116 TBD - enable a way to actually call the syscalls as we test their 1117 events 1118 1119config FTRACE_SORT_STARTUP_TEST 1120 bool "Verify compile time sorting of ftrace functions" 1121 depends on DYNAMIC_FTRACE 1122 depends on BUILDTIME_MCOUNT_SORT 1123 help 1124 Sorting of the mcount_loc sections that is used to find the 1125 where the ftrace knows where to patch functions for tracing 1126 and other callbacks is done at compile time. But if the sort 1127 is not done correctly, it will cause non-deterministic failures. 1128 When this is set, the sorted sections will be verified that they 1129 are in deed sorted and will warn if they are not. 1130 1131 If unsure, say N 1132 1133config RING_BUFFER_STARTUP_TEST 1134 bool "Ring buffer startup self test" 1135 depends on RING_BUFFER 1136 help 1137 Run a simple self test on the ring buffer on boot up. Late in the 1138 kernel boot sequence, the test will start that kicks off 1139 a thread per cpu. Each thread will write various size events 1140 into the ring buffer. Another thread is created to send IPIs 1141 to each of the threads, where the IPI handler will also write 1142 to the ring buffer, to test/stress the nesting ability. 1143 If any anomalies are discovered, a warning will be displayed 1144 and all ring buffers will be disabled. 1145 1146 The test runs for 10 seconds. This will slow your boot time 1147 by at least 10 more seconds. 1148 1149 At the end of the test, statistics and more checks are done. 1150 It will output the stats of each per cpu buffer: What 1151 was written, the sizes, what was read, what was lost, and 1152 other similar details. 1153 1154 If unsure, say N 1155 1156config RING_BUFFER_VALIDATE_TIME_DELTAS 1157 bool "Verify ring buffer time stamp deltas" 1158 depends on RING_BUFFER 1159 help 1160 This will audit the time stamps on the ring buffer sub 1161 buffer to make sure that all the time deltas for the 1162 events on a sub buffer matches the current time stamp. 1163 This audit is performed for every event that is not 1164 interrupted, or interrupting another event. A check 1165 is also made when traversing sub buffers to make sure 1166 that all the deltas on the previous sub buffer do not 1167 add up to be greater than the current time stamp. 1168 1169 NOTE: This adds significant overhead to recording of events, 1170 and should only be used to test the logic of the ring buffer. 1171 Do not use it on production systems. 1172 1173 Only say Y if you understand what this does, and you 1174 still want it enabled. Otherwise say N 1175 1176config MMIOTRACE_TEST 1177 tristate "Test module for mmiotrace" 1178 depends on MMIOTRACE && m 1179 help 1180 This is a dumb module for testing mmiotrace. It is very dangerous 1181 as it will write garbage to IO memory starting at a given address. 1182 However, it should be safe to use on e.g. unused portion of VRAM. 1183 1184 Say N, unless you absolutely know what you are doing. 1185 1186config PREEMPTIRQ_DELAY_TEST 1187 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers" 1188 depends on m 1189 help 1190 Select this option to build a test module that can help test latency 1191 tracers by executing a preempt or irq disable section with a user 1192 configurable delay. The module busy waits for the duration of the 1193 critical section. 1194 1195 For example, the following invocation generates a burst of three 1196 irq-disabled critical sections for 500us: 1197 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3 1198 1199 What's more, if you want to attach the test on the cpu which the latency 1200 tracer is running on, specify cpu_affinity=cpu_num at the end of the 1201 command. 1202 1203 If unsure, say N 1204 1205config SYNTH_EVENT_GEN_TEST 1206 tristate "Test module for in-kernel synthetic event generation" 1207 depends on SYNTH_EVENTS && m 1208 help 1209 This option creates a test module to check the base 1210 functionality of in-kernel synthetic event definition and 1211 generation. 1212 1213 To test, insert the module, and then check the trace buffer 1214 for the generated sample events. 1215 1216 If unsure, say N. 1217 1218config KPROBE_EVENT_GEN_TEST 1219 tristate "Test module for in-kernel kprobe event generation" 1220 depends on KPROBE_EVENTS && m 1221 help 1222 This option creates a test module to check the base 1223 functionality of in-kernel kprobe event definition. 1224 1225 To test, insert the module, and then check the trace buffer 1226 for the generated kprobe events. 1227 1228 If unsure, say N. 1229 1230config HIST_TRIGGERS_DEBUG 1231 bool "Hist trigger debug support" 1232 depends on HIST_TRIGGERS 1233 help 1234 Add "hist_debug" file for each event, which when read will 1235 dump out a bunch of internal details about the hist triggers 1236 defined on that event. 1237 1238 The hist_debug file serves a couple of purposes: 1239 1240 - Helps developers verify that nothing is broken. 1241 1242 - Provides educational information to support the details 1243 of the hist trigger internals as described by 1244 Documentation/trace/histogram-design.rst. 1245 1246 The hist_debug output only covers the data structures 1247 related to the histogram definitions themselves and doesn't 1248 display the internals of map buckets or variable values of 1249 running histograms. 1250 1251 If unsure, say N. 1252 1253source "kernel/trace/rv/Kconfig" 1254 1255endif # FTRACE 1256