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