1# 2# Architectures that offer an FUNCTION_TRACER implementation should 3# select HAVE_FUNCTION_TRACER: 4# 5 6config USER_STACKTRACE_SUPPORT 7 bool 8 9config NOP_TRACER 10 bool 11 12config HAVE_FTRACE_NMI_ENTER 13 bool 14 help 15 See Documentation/trace/ftrace-design.txt 16 17config HAVE_FUNCTION_TRACER 18 bool 19 help 20 See Documentation/trace/ftrace-design.txt 21 22config HAVE_FUNCTION_GRAPH_TRACER 23 bool 24 help 25 See Documentation/trace/ftrace-design.txt 26 27config HAVE_FUNCTION_GRAPH_FP_TEST 28 bool 29 help 30 See Documentation/trace/ftrace-design.txt 31 32config HAVE_FUNCTION_TRACE_MCOUNT_TEST 33 bool 34 help 35 See Documentation/trace/ftrace-design.txt 36 37config HAVE_DYNAMIC_FTRACE 38 bool 39 help 40 See Documentation/trace/ftrace-design.txt 41 42config HAVE_FTRACE_MCOUNT_RECORD 43 bool 44 help 45 See Documentation/trace/ftrace-design.txt 46 47config HAVE_SYSCALL_TRACEPOINTS 48 bool 49 help 50 See Documentation/trace/ftrace-design.txt 51 52config TRACER_MAX_TRACE 53 bool 54 55config RING_BUFFER 56 bool 57 58config FTRACE_NMI_ENTER 59 bool 60 depends on HAVE_FTRACE_NMI_ENTER 61 default y 62 63config EVENT_TRACING 64 select CONTEXT_SWITCH_TRACER 65 bool 66 67config CONTEXT_SWITCH_TRACER 68 bool 69 70config RING_BUFFER_ALLOW_SWAP 71 bool 72 help 73 Allow the use of ring_buffer_swap_cpu. 74 Adds a very slight overhead to tracing when enabled. 75 76# All tracer options should select GENERIC_TRACER. For those options that are 77# enabled by all tracers (context switch and event tracer) they select TRACING. 78# This allows those options to appear when no other tracer is selected. But the 79# options do not appear when something else selects it. We need the two options 80# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the 81# hiding of the automatic options. 82 83config TRACING 84 bool 85 select DEBUG_FS 86 select RING_BUFFER 87 select STACKTRACE if STACKTRACE_SUPPORT 88 select TRACEPOINTS 89 select NOP_TRACER 90 select BINARY_PRINTF 91 select EVENT_TRACING 92 93config GENERIC_TRACER 94 bool 95 select TRACING 96 97# 98# Minimum requirements an architecture has to meet for us to 99# be able to offer generic tracing facilities: 100# 101config TRACING_SUPPORT 102 bool 103 # PPC32 has no irqflags tracing support, but it can use most of the 104 # tracers anyway, they were tested to build and work. Note that new 105 # exceptions to this list aren't welcomed, better implement the 106 # irqflags tracing for your architecture. 107 depends on TRACE_IRQFLAGS_SUPPORT || PPC32 108 depends on STACKTRACE_SUPPORT 109 default y 110 111if TRACING_SUPPORT 112 113menuconfig FTRACE 114 bool "Tracers" 115 default y if DEBUG_KERNEL 116 help 117 Enable the kernel tracing infrastructure. 118 119if FTRACE 120 121config FUNCTION_TRACER 122 bool "Kernel Function Tracer" 123 depends on HAVE_FUNCTION_TRACER 124 select FRAME_POINTER 125 select KALLSYMS 126 select GENERIC_TRACER 127 select CONTEXT_SWITCH_TRACER 128 help 129 Enable the kernel to trace every kernel function. This is done 130 by using a compiler feature to insert a small, 5-byte No-Operation 131 instruction at the beginning of every kernel function, which NOP 132 sequence is then dynamically patched into a tracer call when 133 tracing is enabled by the administrator. If it's runtime disabled 134 (the bootup default), then the overhead of the instructions is very 135 small and not measurable even in micro-benchmarks. 136 137config FUNCTION_GRAPH_TRACER 138 bool "Kernel Function Graph Tracer" 139 depends on HAVE_FUNCTION_GRAPH_TRACER 140 depends on FUNCTION_TRACER 141 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE 142 default y 143 help 144 Enable the kernel to trace a function at both its return 145 and its entry. 146 Its first purpose is to trace the duration of functions and 147 draw a call graph for each thread with some information like 148 the return value. This is done by setting the current return 149 address on the current task structure into a stack of calls. 150 151 152config IRQSOFF_TRACER 153 bool "Interrupts-off Latency Tracer" 154 default n 155 depends on TRACE_IRQFLAGS_SUPPORT 156 depends on GENERIC_TIME 157 select TRACE_IRQFLAGS 158 select GENERIC_TRACER 159 select TRACER_MAX_TRACE 160 select RING_BUFFER_ALLOW_SWAP 161 help 162 This option measures the time spent in irqs-off critical 163 sections, with microsecond accuracy. 164 165 The default measurement method is a maximum search, which is 166 disabled by default and can be runtime (re-)started 167 via: 168 169 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 170 171 (Note that kernel size and overhead increase with this option 172 enabled. This option and the preempt-off timing option can be 173 used together or separately.) 174 175config PREEMPT_TRACER 176 bool "Preemption-off Latency Tracer" 177 default n 178 depends on GENERIC_TIME 179 depends on PREEMPT 180 select GENERIC_TRACER 181 select TRACER_MAX_TRACE 182 select RING_BUFFER_ALLOW_SWAP 183 help 184 This option measures the time spent in preemption-off critical 185 sections, with microsecond accuracy. 186 187 The default measurement method is a maximum search, which is 188 disabled by default and can be runtime (re-)started 189 via: 190 191 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency 192 193 (Note that kernel size and overhead increase with this option 194 enabled. This option and the irqs-off timing option can be 195 used together or separately.) 196 197config SYSPROF_TRACER 198 bool "Sysprof Tracer" 199 depends on X86 200 select GENERIC_TRACER 201 select CONTEXT_SWITCH_TRACER 202 help 203 This tracer provides the trace needed by the 'Sysprof' userspace 204 tool. 205 206config SCHED_TRACER 207 bool "Scheduling Latency Tracer" 208 select GENERIC_TRACER 209 select CONTEXT_SWITCH_TRACER 210 select TRACER_MAX_TRACE 211 help 212 This tracer tracks the latency of the highest priority task 213 to be scheduled in, starting from the point it has woken up. 214 215config ENABLE_DEFAULT_TRACERS 216 bool "Trace process context switches and events" 217 depends on !GENERIC_TRACER 218 select TRACING 219 help 220 This tracer hooks to various trace points in the kernel, 221 allowing the user to pick and choose which trace point they 222 want to trace. It also includes the sched_switch tracer plugin. 223 224config FTRACE_SYSCALLS 225 bool "Trace syscalls" 226 depends on HAVE_SYSCALL_TRACEPOINTS 227 select GENERIC_TRACER 228 select KALLSYMS 229 help 230 Basic tracer to catch the syscall entry and exit events. 231 232config TRACE_BRANCH_PROFILING 233 bool 234 select GENERIC_TRACER 235 236choice 237 prompt "Branch Profiling" 238 default BRANCH_PROFILE_NONE 239 help 240 The branch profiling is a software profiler. It will add hooks 241 into the C conditionals to test which path a branch takes. 242 243 The likely/unlikely profiler only looks at the conditions that 244 are annotated with a likely or unlikely macro. 245 246 The "all branch" profiler will profile every if-statement in the 247 kernel. This profiler will also enable the likely/unlikely 248 profiler. 249 250 Either of the above profilers adds a bit of overhead to the system. 251 If unsure, choose "No branch profiling". 252 253config BRANCH_PROFILE_NONE 254 bool "No branch profiling" 255 help 256 No branch profiling. Branch profiling adds a bit of overhead. 257 Only enable it if you want to analyse the branching behavior. 258 Otherwise keep it disabled. 259 260config PROFILE_ANNOTATED_BRANCHES 261 bool "Trace likely/unlikely profiler" 262 select TRACE_BRANCH_PROFILING 263 help 264 This tracer profiles all the the likely and unlikely macros 265 in the kernel. It will display the results in: 266 267 /sys/kernel/debug/tracing/profile_annotated_branch 268 269 Note: this will add a significant overhead; only turn this 270 on if you need to profile the system's use of these macros. 271 272config PROFILE_ALL_BRANCHES 273 bool "Profile all if conditionals" 274 select TRACE_BRANCH_PROFILING 275 help 276 This tracer profiles all branch conditions. Every if () 277 taken in the kernel is recorded whether it hit or miss. 278 The results will be displayed in: 279 280 /sys/kernel/debug/tracing/profile_branch 281 282 This option also enables the likely/unlikely profiler. 283 284 This configuration, when enabled, will impose a great overhead 285 on the system. This should only be enabled when the system 286 is to be analyzed in much detail. 287endchoice 288 289config TRACING_BRANCHES 290 bool 291 help 292 Selected by tracers that will trace the likely and unlikely 293 conditions. This prevents the tracers themselves from being 294 profiled. Profiling the tracing infrastructure can only happen 295 when the likelys and unlikelys are not being traced. 296 297config BRANCH_TRACER 298 bool "Trace likely/unlikely instances" 299 depends on TRACE_BRANCH_PROFILING 300 select TRACING_BRANCHES 301 help 302 This traces the events of likely and unlikely condition 303 calls in the kernel. The difference between this and the 304 "Trace likely/unlikely profiler" is that this is not a 305 histogram of the callers, but actually places the calling 306 events into a running trace buffer to see when and where the 307 events happened, as well as their results. 308 309 Say N if unsure. 310 311config STACK_TRACER 312 bool "Trace max stack" 313 depends on HAVE_FUNCTION_TRACER 314 select FUNCTION_TRACER 315 select STACKTRACE 316 select KALLSYMS 317 help 318 This special tracer records the maximum stack footprint of the 319 kernel and displays it in /sys/kernel/debug/tracing/stack_trace. 320 321 This tracer works by hooking into every function call that the 322 kernel executes, and keeping a maximum stack depth value and 323 stack-trace saved. If this is configured with DYNAMIC_FTRACE 324 then it will not have any overhead while the stack tracer 325 is disabled. 326 327 To enable the stack tracer on bootup, pass in 'stacktrace' 328 on the kernel command line. 329 330 The stack tracer can also be enabled or disabled via the 331 sysctl kernel.stack_tracer_enabled 332 333 Say N if unsure. 334 335config WORKQUEUE_TRACER 336 bool "Trace workqueues" 337 select GENERIC_TRACER 338 help 339 The workqueue tracer provides some statistical information 340 about each cpu workqueue thread such as the number of the 341 works inserted and executed since their creation. It can help 342 to evaluate the amount of work each of them has to perform. 343 For example it can help a developer to decide whether he should 344 choose a per-cpu workqueue instead of a singlethreaded one. 345 346config BLK_DEV_IO_TRACE 347 bool "Support for tracing block IO actions" 348 depends on SYSFS 349 depends on BLOCK 350 select RELAY 351 select DEBUG_FS 352 select TRACEPOINTS 353 select GENERIC_TRACER 354 select STACKTRACE 355 help 356 Say Y here if you want to be able to trace the block layer actions 357 on a given queue. Tracing allows you to see any traffic happening 358 on a block device queue. For more information (and the userspace 359 support tools needed), fetch the blktrace tools from: 360 361 git://git.kernel.dk/blktrace.git 362 363 Tracing also is possible using the ftrace interface, e.g.: 364 365 echo 1 > /sys/block/sda/sda1/trace/enable 366 echo blk > /sys/kernel/debug/tracing/current_tracer 367 cat /sys/kernel/debug/tracing/trace_pipe 368 369 If unsure, say N. 370 371config KPROBE_EVENT 372 depends on KPROBES 373 depends on HAVE_REGS_AND_STACK_ACCESS_API 374 bool "Enable kprobes-based dynamic events" 375 select TRACING 376 default y 377 help 378 This allows the user to add tracing events (similar to tracepoints) 379 on the fly via the ftrace interface. See 380 Documentation/trace/kprobetrace.txt for more details. 381 382 Those events can be inserted wherever kprobes can probe, and record 383 various register and memory values. 384 385 This option is also required by perf-probe subcommand of perf tools. 386 If you want to use perf tools, this option is strongly recommended. 387 388config DYNAMIC_FTRACE 389 bool "enable/disable ftrace tracepoints dynamically" 390 depends on FUNCTION_TRACER 391 depends on HAVE_DYNAMIC_FTRACE 392 default y 393 help 394 This option will modify all the calls to ftrace dynamically 395 (will patch them out of the binary image and replace them 396 with a No-Op instruction) as they are called. A table is 397 created to dynamically enable them again. 398 399 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 400 otherwise has native performance as long as no tracing is active. 401 402 The changes to the code are done by a kernel thread that 403 wakes up once a second and checks to see if any ftrace calls 404 were made. If so, it runs stop_machine (stops all CPUS) 405 and modifies the code to jump over the call to ftrace. 406 407config FUNCTION_PROFILER 408 bool "Kernel function profiler" 409 depends on FUNCTION_TRACER 410 default n 411 help 412 This option enables the kernel function profiler. A file is created 413 in debugfs called function_profile_enabled which defaults to zero. 414 When a 1 is echoed into this file profiling begins, and when a 415 zero is entered, profiling stops. A "functions" file is created in 416 the trace_stats directory; this file shows the list of functions that 417 have been hit and their counters. 418 419 If in doubt, say N. 420 421config FTRACE_MCOUNT_RECORD 422 def_bool y 423 depends on DYNAMIC_FTRACE 424 depends on HAVE_FTRACE_MCOUNT_RECORD 425 426config FTRACE_SELFTEST 427 bool 428 429config FTRACE_STARTUP_TEST 430 bool "Perform a startup test on ftrace" 431 depends on GENERIC_TRACER 432 select FTRACE_SELFTEST 433 help 434 This option performs a series of startup tests on ftrace. On bootup 435 a series of tests are made to verify that the tracer is 436 functioning properly. It will do tests on all the configured 437 tracers of ftrace. 438 439config EVENT_TRACE_TEST_SYSCALLS 440 bool "Run selftest on syscall events" 441 depends on FTRACE_STARTUP_TEST 442 help 443 This option will also enable testing every syscall event. 444 It only enables the event and disables it and runs various loads 445 with the event enabled. This adds a bit more time for kernel boot 446 up since it runs this on every system call defined. 447 448 TBD - enable a way to actually call the syscalls as we test their 449 events 450 451config MMIOTRACE 452 bool "Memory mapped IO tracing" 453 depends on HAVE_MMIOTRACE_SUPPORT && PCI 454 select GENERIC_TRACER 455 help 456 Mmiotrace traces Memory Mapped I/O access and is meant for 457 debugging and reverse engineering. It is called from the ioremap 458 implementation and works via page faults. Tracing is disabled by 459 default and can be enabled at run-time. 460 461 See Documentation/trace/mmiotrace.txt. 462 If you are not helping to develop drivers, say N. 463 464config MMIOTRACE_TEST 465 tristate "Test module for mmiotrace" 466 depends on MMIOTRACE && m 467 help 468 This is a dumb module for testing mmiotrace. It is very dangerous 469 as it will write garbage to IO memory starting at a given address. 470 However, it should be safe to use on e.g. unused portion of VRAM. 471 472 Say N, unless you absolutely know what you are doing. 473 474config RING_BUFFER_BENCHMARK 475 tristate "Ring buffer benchmark stress tester" 476 depends on RING_BUFFER 477 help 478 This option creates a test to stress the ring buffer and benchmark it. 479 It creates its own ring buffer such that it will not interfere with 480 any other users of the ring buffer (such as ftrace). It then creates 481 a producer and consumer that will run for 10 seconds and sleep for 482 10 seconds. Each interval it will print out the number of events 483 it recorded and give a rough estimate of how long each iteration took. 484 485 It does not disable interrupts or raise its priority, so it may be 486 affected by processes that are running. 487 488 If unsure, say N. 489 490endif # FTRACE 491 492endif # TRACING_SUPPORT 493 494