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 PREEMPTIRQ_EVENTS 253 bool "Enable trace events for preempt and irq disable/enable" 254 select TRACE_IRQFLAGS 255 select TRACE_PREEMPT_TOGGLE if PREEMPTION 256 select GENERIC_TRACER 257 default n 258 help 259 Enable tracing of disable and enable events for preemption and irqs. 260 261config IRQSOFF_TRACER 262 bool "Interrupts-off Latency Tracer" 263 default n 264 depends on TRACE_IRQFLAGS_SUPPORT 265 depends on !ARCH_USES_GETTIMEOFFSET 266 select TRACE_IRQFLAGS 267 select GENERIC_TRACER 268 select TRACER_MAX_TRACE 269 select RING_BUFFER_ALLOW_SWAP 270 select TRACER_SNAPSHOT 271 select TRACER_SNAPSHOT_PER_CPU_SWAP 272 help 273 This option measures the time spent in irqs-off critical 274 sections, with microsecond accuracy. 275 276 The default measurement method is a maximum search, which is 277 disabled by default and can be runtime (re-)started 278 via: 279 280 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 281 282 (Note that kernel size and overhead increase with this option 283 enabled. This option and the preempt-off timing option can be 284 used together or separately.) 285 286config PREEMPT_TRACER 287 bool "Preemption-off Latency Tracer" 288 default n 289 depends on !ARCH_USES_GETTIMEOFFSET 290 depends on PREEMPTION 291 select GENERIC_TRACER 292 select TRACER_MAX_TRACE 293 select RING_BUFFER_ALLOW_SWAP 294 select TRACER_SNAPSHOT 295 select TRACER_SNAPSHOT_PER_CPU_SWAP 296 select TRACE_PREEMPT_TOGGLE 297 help 298 This option measures the time spent in preemption-off critical 299 sections, with microsecond accuracy. 300 301 The default measurement method is a maximum search, which is 302 disabled by default and can be runtime (re-)started 303 via: 304 305 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 306 307 (Note that kernel size and overhead increase with this option 308 enabled. This option and the irqs-off timing option can be 309 used together or separately.) 310 311config SCHED_TRACER 312 bool "Scheduling Latency Tracer" 313 select GENERIC_TRACER 314 select CONTEXT_SWITCH_TRACER 315 select TRACER_MAX_TRACE 316 select TRACER_SNAPSHOT 317 help 318 This tracer tracks the latency of the highest priority task 319 to be scheduled in, starting from the point it has woken up. 320 321config HWLAT_TRACER 322 bool "Tracer to detect hardware latencies (like SMIs)" 323 select GENERIC_TRACER 324 help 325 This tracer, when enabled will create one or more kernel threads, 326 depending on what the cpumask file is set to, which each thread 327 spinning in a loop looking for interruptions caused by 328 something other than the kernel. For example, if a 329 System Management Interrupt (SMI) takes a noticeable amount of 330 time, this tracer will detect it. This is useful for testing 331 if a system is reliable for Real Time tasks. 332 333 Some files are created in the tracing directory when this 334 is enabled: 335 336 hwlat_detector/width - time in usecs for how long to spin for 337 hwlat_detector/window - time in usecs between the start of each 338 iteration 339 340 A kernel thread is created that will spin with interrupts disabled 341 for "width" microseconds in every "window" cycle. It will not spin 342 for "window - width" microseconds, where the system can 343 continue to operate. 344 345 The output will appear in the trace and trace_pipe files. 346 347 When the tracer is not running, it has no affect on the system, 348 but when it is running, it can cause the system to be 349 periodically non responsive. Do not run this tracer on a 350 production system. 351 352 To enable this tracer, echo in "hwlat" into the current_tracer 353 file. Every time a latency is greater than tracing_thresh, it will 354 be recorded into the ring buffer. 355 356config MMIOTRACE 357 bool "Memory mapped IO tracing" 358 depends on HAVE_MMIOTRACE_SUPPORT && PCI 359 select GENERIC_TRACER 360 help 361 Mmiotrace traces Memory Mapped I/O access and is meant for 362 debugging and reverse engineering. It is called from the ioremap 363 implementation and works via page faults. Tracing is disabled by 364 default and can be enabled at run-time. 365 366 See Documentation/trace/mmiotrace.rst. 367 If you are not helping to develop drivers, say N. 368 369config ENABLE_DEFAULT_TRACERS 370 bool "Trace process context switches and events" 371 depends on !GENERIC_TRACER 372 select TRACING 373 help 374 This tracer hooks to various trace points in the kernel, 375 allowing the user to pick and choose which trace point they 376 want to trace. It also includes the sched_switch tracer plugin. 377 378config FTRACE_SYSCALLS 379 bool "Trace syscalls" 380 depends on HAVE_SYSCALL_TRACEPOINTS 381 select GENERIC_TRACER 382 select KALLSYMS 383 help 384 Basic tracer to catch the syscall entry and exit events. 385 386config TRACER_SNAPSHOT 387 bool "Create a snapshot trace buffer" 388 select TRACER_MAX_TRACE 389 help 390 Allow tracing users to take snapshot of the current buffer using the 391 ftrace interface, e.g.: 392 393 echo 1 > /sys/kernel/debug/tracing/snapshot 394 cat snapshot 395 396config TRACER_SNAPSHOT_PER_CPU_SWAP 397 bool "Allow snapshot to swap per CPU" 398 depends on TRACER_SNAPSHOT 399 select RING_BUFFER_ALLOW_SWAP 400 help 401 Allow doing a snapshot of a single CPU buffer instead of a 402 full swap (all buffers). If this is set, then the following is 403 allowed: 404 405 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot 406 407 After which, only the tracing buffer for CPU 2 was swapped with 408 the main tracing buffer, and the other CPU buffers remain the same. 409 410 When this is enabled, this adds a little more overhead to the 411 trace recording, as it needs to add some checks to synchronize 412 recording with swaps. But this does not affect the performance 413 of the overall system. This is enabled by default when the preempt 414 or irq latency tracers are enabled, as those need to swap as well 415 and already adds the overhead (plus a lot more). 416 417config TRACE_BRANCH_PROFILING 418 bool 419 select GENERIC_TRACER 420 421choice 422 prompt "Branch Profiling" 423 default BRANCH_PROFILE_NONE 424 help 425 The branch profiling is a software profiler. It will add hooks 426 into the C conditionals to test which path a branch takes. 427 428 The likely/unlikely profiler only looks at the conditions that 429 are annotated with a likely or unlikely macro. 430 431 The "all branch" profiler will profile every if-statement in the 432 kernel. This profiler will also enable the likely/unlikely 433 profiler. 434 435 Either of the above profilers adds a bit of overhead to the system. 436 If unsure, choose "No branch profiling". 437 438config BRANCH_PROFILE_NONE 439 bool "No branch profiling" 440 help 441 No branch profiling. Branch profiling adds a bit of overhead. 442 Only enable it if you want to analyse the branching behavior. 443 Otherwise keep it disabled. 444 445config PROFILE_ANNOTATED_BRANCHES 446 bool "Trace likely/unlikely profiler" 447 select TRACE_BRANCH_PROFILING 448 help 449 This tracer profiles all likely and unlikely macros 450 in the kernel. It will display the results in: 451 452 /sys/kernel/debug/tracing/trace_stat/branch_annotated 453 454 Note: this will add a significant overhead; only turn this 455 on if you need to profile the system's use of these macros. 456 457config PROFILE_ALL_BRANCHES 458 bool "Profile all if conditionals" if !FORTIFY_SOURCE 459 select TRACE_BRANCH_PROFILING 460 help 461 This tracer profiles all branch conditions. Every if () 462 taken in the kernel is recorded whether it hit or miss. 463 The results will be displayed in: 464 465 /sys/kernel/debug/tracing/trace_stat/branch_all 466 467 This option also enables the likely/unlikely profiler. 468 469 This configuration, when enabled, will impose a great overhead 470 on the system. This should only be enabled when the system 471 is to be analyzed in much detail. 472endchoice 473 474config TRACING_BRANCHES 475 bool 476 help 477 Selected by tracers that will trace the likely and unlikely 478 conditions. This prevents the tracers themselves from being 479 profiled. Profiling the tracing infrastructure can only happen 480 when the likelys and unlikelys are not being traced. 481 482config BRANCH_TRACER 483 bool "Trace likely/unlikely instances" 484 depends on TRACE_BRANCH_PROFILING 485 select TRACING_BRANCHES 486 help 487 This traces the events of likely and unlikely condition 488 calls in the kernel. The difference between this and the 489 "Trace likely/unlikely profiler" is that this is not a 490 histogram of the callers, but actually places the calling 491 events into a running trace buffer to see when and where the 492 events happened, as well as their results. 493 494 Say N if unsure. 495 496config BLK_DEV_IO_TRACE 497 bool "Support for tracing block IO actions" 498 depends on SYSFS 499 depends on BLOCK 500 select RELAY 501 select DEBUG_FS 502 select TRACEPOINTS 503 select GENERIC_TRACER 504 select STACKTRACE 505 help 506 Say Y here if you want to be able to trace the block layer actions 507 on a given queue. Tracing allows you to see any traffic happening 508 on a block device queue. For more information (and the userspace 509 support tools needed), fetch the blktrace tools from: 510 511 git://git.kernel.dk/blktrace.git 512 513 Tracing also is possible using the ftrace interface, e.g.: 514 515 echo 1 > /sys/block/sda/sda1/trace/enable 516 echo blk > /sys/kernel/debug/tracing/current_tracer 517 cat /sys/kernel/debug/tracing/trace_pipe 518 519 If unsure, say N. 520 521config KPROBE_EVENTS 522 depends on KPROBES 523 depends on HAVE_REGS_AND_STACK_ACCESS_API 524 bool "Enable kprobes-based dynamic events" 525 select TRACING 526 select PROBE_EVENTS 527 select DYNAMIC_EVENTS 528 default y 529 help 530 This allows the user to add tracing events (similar to tracepoints) 531 on the fly via the ftrace interface. See 532 Documentation/trace/kprobetrace.rst for more details. 533 534 Those events can be inserted wherever kprobes can probe, and record 535 various register and memory values. 536 537 This option is also required by perf-probe subcommand of perf tools. 538 If you want to use perf tools, this option is strongly recommended. 539 540config KPROBE_EVENTS_ON_NOTRACE 541 bool "Do NOT protect notrace function from kprobe events" 542 depends on KPROBE_EVENTS 543 depends on KPROBES_ON_FTRACE 544 default n 545 help 546 This is only for the developers who want to debug ftrace itself 547 using kprobe events. 548 549 If kprobes can use ftrace instead of breakpoint, ftrace related 550 functions are protected from kprobe-events to prevent an infinit 551 recursion or any unexpected execution path which leads to a kernel 552 crash. 553 554 This option disables such protection and allows you to put kprobe 555 events on ftrace functions for debugging ftrace by itself. 556 Note that this might let you shoot yourself in the foot. 557 558 If unsure, say N. 559 560config UPROBE_EVENTS 561 bool "Enable uprobes-based dynamic events" 562 depends on ARCH_SUPPORTS_UPROBES 563 depends on MMU 564 depends on PERF_EVENTS 565 select UPROBES 566 select PROBE_EVENTS 567 select DYNAMIC_EVENTS 568 select TRACING 569 default y 570 help 571 This allows the user to add tracing events on top of userspace 572 dynamic events (similar to tracepoints) on the fly via the trace 573 events interface. Those events can be inserted wherever uprobes 574 can probe, and record various registers. 575 This option is required if you plan to use perf-probe subcommand 576 of perf tools on user space applications. 577 578config BPF_EVENTS 579 depends on BPF_SYSCALL 580 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS 581 bool 582 default y 583 help 584 This allows the user to attach BPF programs to kprobe, uprobe, and 585 tracepoint events. 586 587config DYNAMIC_EVENTS 588 def_bool n 589 590config PROBE_EVENTS 591 def_bool n 592 593config BPF_KPROBE_OVERRIDE 594 bool "Enable BPF programs to override a kprobed function" 595 depends on BPF_EVENTS 596 depends on FUNCTION_ERROR_INJECTION 597 default n 598 help 599 Allows BPF to override the execution of a probed function and 600 set a different return value. This is used for error injection. 601 602config FTRACE_MCOUNT_RECORD 603 def_bool y 604 depends on DYNAMIC_FTRACE 605 depends on HAVE_FTRACE_MCOUNT_RECORD 606 607config TRACING_MAP 608 bool 609 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 610 help 611 tracing_map is a special-purpose lock-free map for tracing, 612 separated out as a stand-alone facility in order to allow it 613 to be shared between multiple tracers. It isn't meant to be 614 generally used outside of that context, and is normally 615 selected by tracers that use it. 616 617config HIST_TRIGGERS 618 bool "Histogram triggers" 619 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 620 select TRACING_MAP 621 select TRACING 622 select DYNAMIC_EVENTS 623 default n 624 help 625 Hist triggers allow one or more arbitrary trace event fields 626 to be aggregated into hash tables and dumped to stdout by 627 reading a debugfs/tracefs file. They're useful for 628 gathering quick and dirty (though precise) summaries of 629 event activity as an initial guide for further investigation 630 using more advanced tools. 631 632 Inter-event tracing of quantities such as latencies is also 633 supported using hist triggers under this option. 634 635 See Documentation/trace/histogram.rst. 636 If in doubt, say N. 637 638config TRACE_EVENT_INJECT 639 bool "Trace event injection" 640 depends on TRACING 641 help 642 Allow user-space to inject a specific trace event into the ring 643 buffer. This is mainly used for testing purpose. 644 645 If unsure, say N. 646 647config TRACEPOINT_BENCHMARK 648 bool "Add tracepoint that benchmarks tracepoints" 649 help 650 This option creates the tracepoint "benchmark:benchmark_event". 651 When the tracepoint is enabled, it kicks off a kernel thread that 652 goes into an infinite loop (calling cond_sched() to let other tasks 653 run), and calls the tracepoint. Each iteration will record the time 654 it took to write to the tracepoint and the next iteration that 655 data will be passed to the tracepoint itself. That is, the tracepoint 656 will report the time it took to do the previous tracepoint. 657 The string written to the tracepoint is a static string of 128 bytes 658 to keep the time the same. The initial string is simply a write of 659 "START". The second string records the cold cache time of the first 660 write which is not added to the rest of the calculations. 661 662 As it is a tight loop, it benchmarks as hot cache. That's fine because 663 we care most about hot paths that are probably in cache already. 664 665 An example of the output: 666 667 START 668 first=3672 [COLD CACHED] 669 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712 670 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337 671 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064 672 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411 673 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389 674 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666 675 676 677config RING_BUFFER_BENCHMARK 678 tristate "Ring buffer benchmark stress tester" 679 depends on RING_BUFFER 680 help 681 This option creates a test to stress the ring buffer and benchmark it. 682 It creates its own ring buffer such that it will not interfere with 683 any other users of the ring buffer (such as ftrace). It then creates 684 a producer and consumer that will run for 10 seconds and sleep for 685 10 seconds. Each interval it will print out the number of events 686 it recorded and give a rough estimate of how long each iteration took. 687 688 It does not disable interrupts or raise its priority, so it may be 689 affected by processes that are running. 690 691 If unsure, say N. 692 693config TRACE_EVAL_MAP_FILE 694 bool "Show eval mappings for trace events" 695 depends on TRACING 696 help 697 The "print fmt" of the trace events will show the enum/sizeof names 698 instead of their values. This can cause problems for user space tools 699 that use this string to parse the raw data as user space does not know 700 how to convert the string to its value. 701 702 To fix this, there's a special macro in the kernel that can be used 703 to convert an enum/sizeof into its value. If this macro is used, then 704 the print fmt strings will be converted to their values. 705 706 If something does not get converted properly, this option can be 707 used to show what enums/sizeof the kernel tried to convert. 708 709 This option is for debugging the conversions. A file is created 710 in the tracing directory called "eval_map" that will show the 711 names matched with their values and what trace event system they 712 belong too. 713 714 Normally, the mapping of the strings to values will be freed after 715 boot up or module load. With this option, they will not be freed, as 716 they are needed for the "eval_map" file. Enabling this option will 717 increase the memory footprint of the running kernel. 718 719 If unsure, say N. 720 721config GCOV_PROFILE_FTRACE 722 bool "Enable GCOV profiling on ftrace subsystem" 723 depends on GCOV_KERNEL 724 help 725 Enable GCOV profiling on ftrace subsystem for checking 726 which functions/lines are tested. 727 728 If unsure, say N. 729 730 Note that on a kernel compiled with this config, ftrace will 731 run significantly slower. 732 733config FTRACE_SELFTEST 734 bool 735 736config FTRACE_STARTUP_TEST 737 bool "Perform a startup test on ftrace" 738 depends on GENERIC_TRACER 739 select FTRACE_SELFTEST 740 help 741 This option performs a series of startup tests on ftrace. On bootup 742 a series of tests are made to verify that the tracer is 743 functioning properly. It will do tests on all the configured 744 tracers of ftrace. 745 746config EVENT_TRACE_STARTUP_TEST 747 bool "Run selftest on trace events" 748 depends on FTRACE_STARTUP_TEST 749 default y 750 help 751 This option performs a test on all trace events in the system. 752 It basically just enables each event and runs some code that 753 will trigger events (not necessarily the event it enables) 754 This may take some time run as there are a lot of events. 755 756config EVENT_TRACE_TEST_SYSCALLS 757 bool "Run selftest on syscall events" 758 depends on EVENT_TRACE_STARTUP_TEST 759 help 760 This option will also enable testing every syscall event. 761 It only enables the event and disables it and runs various loads 762 with the event enabled. This adds a bit more time for kernel boot 763 up since it runs this on every system call defined. 764 765 TBD - enable a way to actually call the syscalls as we test their 766 events 767 768config RING_BUFFER_STARTUP_TEST 769 bool "Ring buffer startup self test" 770 depends on RING_BUFFER 771 help 772 Run a simple self test on the ring buffer on boot up. Late in the 773 kernel boot sequence, the test will start that kicks off 774 a thread per cpu. Each thread will write various size events 775 into the ring buffer. Another thread is created to send IPIs 776 to each of the threads, where the IPI handler will also write 777 to the ring buffer, to test/stress the nesting ability. 778 If any anomalies are discovered, a warning will be displayed 779 and all ring buffers will be disabled. 780 781 The test runs for 10 seconds. This will slow your boot time 782 by at least 10 more seconds. 783 784 At the end of the test, statics and more checks are done. 785 It will output the stats of each per cpu buffer. What 786 was written, the sizes, what was read, what was lost, and 787 other similar details. 788 789 If unsure, say N 790 791config MMIOTRACE_TEST 792 tristate "Test module for mmiotrace" 793 depends on MMIOTRACE && m 794 help 795 This is a dumb module for testing mmiotrace. It is very dangerous 796 as it will write garbage to IO memory starting at a given address. 797 However, it should be safe to use on e.g. unused portion of VRAM. 798 799 Say N, unless you absolutely know what you are doing. 800 801config PREEMPTIRQ_DELAY_TEST 802 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers" 803 depends on m 804 help 805 Select this option to build a test module that can help test latency 806 tracers by executing a preempt or irq disable section with a user 807 configurable delay. The module busy waits for the duration of the 808 critical section. 809 810 For example, the following invocation generates a burst of three 811 irq-disabled critical sections for 500us: 812 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3 813 814 If unsure, say N 815 816config SYNTH_EVENT_GEN_TEST 817 tristate "Test module for in-kernel synthetic event generation" 818 depends on HIST_TRIGGERS 819 help 820 This option creates a test module to check the base 821 functionality of in-kernel synthetic event definition and 822 generation. 823 824 To test, insert the module, and then check the trace buffer 825 for the generated sample events. 826 827 If unsure, say N. 828 829config KPROBE_EVENT_GEN_TEST 830 tristate "Test module for in-kernel kprobe event generation" 831 depends on KPROBE_EVENTS 832 help 833 This option creates a test module to check the base 834 functionality of in-kernel kprobe event definition. 835 836 To test, insert the module, and then check the trace buffer 837 for the generated kprobe events. 838 839 If unsure, say N. 840 841endif # FTRACE 842 843endif # TRACING_SUPPORT 844 845