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