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