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 SCHED_TRACER 198 bool "Scheduling Latency Tracer" 199 select GENERIC_TRACER 200 select CONTEXT_SWITCH_TRACER 201 select TRACER_MAX_TRACE 202 help 203 This tracer tracks the latency of the highest priority task 204 to be scheduled in, starting from the point it has woken up. 205 206config ENABLE_DEFAULT_TRACERS 207 bool "Trace process context switches and events" 208 depends on !GENERIC_TRACER 209 select TRACING 210 help 211 This tracer hooks to various trace points in the kernel, 212 allowing the user to pick and choose which trace point they 213 want to trace. It also includes the sched_switch tracer plugin. 214 215config FTRACE_SYSCALLS 216 bool "Trace syscalls" 217 depends on HAVE_SYSCALL_TRACEPOINTS 218 select GENERIC_TRACER 219 select KALLSYMS 220 help 221 Basic tracer to catch the syscall entry and exit events. 222 223config TRACE_BRANCH_PROFILING 224 bool 225 select GENERIC_TRACER 226 227choice 228 prompt "Branch Profiling" 229 default BRANCH_PROFILE_NONE 230 help 231 The branch profiling is a software profiler. It will add hooks 232 into the C conditionals to test which path a branch takes. 233 234 The likely/unlikely profiler only looks at the conditions that 235 are annotated with a likely or unlikely macro. 236 237 The "all branch" profiler will profile every if-statement in the 238 kernel. This profiler will also enable the likely/unlikely 239 profiler. 240 241 Either of the above profilers adds a bit of overhead to the system. 242 If unsure, choose "No branch profiling". 243 244config BRANCH_PROFILE_NONE 245 bool "No branch profiling" 246 help 247 No branch profiling. Branch profiling adds a bit of overhead. 248 Only enable it if you want to analyse the branching behavior. 249 Otherwise keep it disabled. 250 251config PROFILE_ANNOTATED_BRANCHES 252 bool "Trace likely/unlikely profiler" 253 select TRACE_BRANCH_PROFILING 254 help 255 This tracer profiles all the the likely and unlikely macros 256 in the kernel. It will display the results in: 257 258 /sys/kernel/debug/tracing/profile_annotated_branch 259 260 Note: this will add a significant overhead; only turn this 261 on if you need to profile the system's use of these macros. 262 263config PROFILE_ALL_BRANCHES 264 bool "Profile all if conditionals" 265 select TRACE_BRANCH_PROFILING 266 help 267 This tracer profiles all branch conditions. Every if () 268 taken in the kernel is recorded whether it hit or miss. 269 The results will be displayed in: 270 271 /sys/kernel/debug/tracing/profile_branch 272 273 This option also enables the likely/unlikely profiler. 274 275 This configuration, when enabled, will impose a great overhead 276 on the system. This should only be enabled when the system 277 is to be analyzed in much detail. 278endchoice 279 280config TRACING_BRANCHES 281 bool 282 help 283 Selected by tracers that will trace the likely and unlikely 284 conditions. This prevents the tracers themselves from being 285 profiled. Profiling the tracing infrastructure can only happen 286 when the likelys and unlikelys are not being traced. 287 288config BRANCH_TRACER 289 bool "Trace likely/unlikely instances" 290 depends on TRACE_BRANCH_PROFILING 291 select TRACING_BRANCHES 292 help 293 This traces the events of likely and unlikely condition 294 calls in the kernel. The difference between this and the 295 "Trace likely/unlikely profiler" is that this is not a 296 histogram of the callers, but actually places the calling 297 events into a running trace buffer to see when and where the 298 events happened, as well as their results. 299 300 Say N if unsure. 301 302config STACK_TRACER 303 bool "Trace max stack" 304 depends on HAVE_FUNCTION_TRACER 305 select FUNCTION_TRACER 306 select STACKTRACE 307 select KALLSYMS 308 help 309 This special tracer records the maximum stack footprint of the 310 kernel and displays it in /sys/kernel/debug/tracing/stack_trace. 311 312 This tracer works by hooking into every function call that the 313 kernel executes, and keeping a maximum stack depth value and 314 stack-trace saved. If this is configured with DYNAMIC_FTRACE 315 then it will not have any overhead while the stack tracer 316 is disabled. 317 318 To enable the stack tracer on bootup, pass in 'stacktrace' 319 on the kernel command line. 320 321 The stack tracer can also be enabled or disabled via the 322 sysctl kernel.stack_tracer_enabled 323 324 Say N if unsure. 325 326config WORKQUEUE_TRACER 327 bool "Trace workqueues" 328 select GENERIC_TRACER 329 help 330 The workqueue tracer provides some statistical information 331 about each cpu workqueue thread such as the number of the 332 works inserted and executed since their creation. It can help 333 to evaluate the amount of work each of them has to perform. 334 For example it can help a developer to decide whether he should 335 choose a per-cpu workqueue instead of a singlethreaded one. 336 337config BLK_DEV_IO_TRACE 338 bool "Support for tracing block IO actions" 339 depends on SYSFS 340 depends on BLOCK 341 select RELAY 342 select DEBUG_FS 343 select TRACEPOINTS 344 select GENERIC_TRACER 345 select STACKTRACE 346 help 347 Say Y here if you want to be able to trace the block layer actions 348 on a given queue. Tracing allows you to see any traffic happening 349 on a block device queue. For more information (and the userspace 350 support tools needed), fetch the blktrace tools from: 351 352 git://git.kernel.dk/blktrace.git 353 354 Tracing also is possible using the ftrace interface, e.g.: 355 356 echo 1 > /sys/block/sda/sda1/trace/enable 357 echo blk > /sys/kernel/debug/tracing/current_tracer 358 cat /sys/kernel/debug/tracing/trace_pipe 359 360 If unsure, say N. 361 362config KPROBE_EVENT 363 depends on KPROBES 364 depends on HAVE_REGS_AND_STACK_ACCESS_API 365 bool "Enable kprobes-based dynamic events" 366 select TRACING 367 default y 368 help 369 This allows the user to add tracing events (similar to tracepoints) 370 on the fly via the ftrace interface. See 371 Documentation/trace/kprobetrace.txt for more details. 372 373 Those events can be inserted wherever kprobes can probe, and record 374 various register and memory values. 375 376 This option is also required by perf-probe subcommand of perf tools. 377 If you want to use perf tools, this option is strongly recommended. 378 379config DYNAMIC_FTRACE 380 bool "enable/disable ftrace tracepoints dynamically" 381 depends on FUNCTION_TRACER 382 depends on HAVE_DYNAMIC_FTRACE 383 default y 384 help 385 This option will modify all the calls to ftrace dynamically 386 (will patch them out of the binary image and replace them 387 with a No-Op instruction) as they are called. A table is 388 created to dynamically enable them again. 389 390 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 391 otherwise has native performance as long as no tracing is active. 392 393 The changes to the code are done by a kernel thread that 394 wakes up once a second and checks to see if any ftrace calls 395 were made. If so, it runs stop_machine (stops all CPUS) 396 and modifies the code to jump over the call to ftrace. 397 398config FUNCTION_PROFILER 399 bool "Kernel function profiler" 400 depends on FUNCTION_TRACER 401 default n 402 help 403 This option enables the kernel function profiler. A file is created 404 in debugfs called function_profile_enabled which defaults to zero. 405 When a 1 is echoed into this file profiling begins, and when a 406 zero is entered, profiling stops. A "functions" file is created in 407 the trace_stats directory; this file shows the list of functions that 408 have been hit and their counters. 409 410 If in doubt, say N. 411 412config FTRACE_MCOUNT_RECORD 413 def_bool y 414 depends on DYNAMIC_FTRACE 415 depends on HAVE_FTRACE_MCOUNT_RECORD 416 417config FTRACE_SELFTEST 418 bool 419 420config FTRACE_STARTUP_TEST 421 bool "Perform a startup test on ftrace" 422 depends on GENERIC_TRACER 423 select FTRACE_SELFTEST 424 help 425 This option performs a series of startup tests on ftrace. On bootup 426 a series of tests are made to verify that the tracer is 427 functioning properly. It will do tests on all the configured 428 tracers of ftrace. 429 430config EVENT_TRACE_TEST_SYSCALLS 431 bool "Run selftest on syscall events" 432 depends on FTRACE_STARTUP_TEST 433 help 434 This option will also enable testing every syscall event. 435 It only enables the event and disables it and runs various loads 436 with the event enabled. This adds a bit more time for kernel boot 437 up since it runs this on every system call defined. 438 439 TBD - enable a way to actually call the syscalls as we test their 440 events 441 442config MMIOTRACE 443 bool "Memory mapped IO tracing" 444 depends on HAVE_MMIOTRACE_SUPPORT && PCI 445 select GENERIC_TRACER 446 help 447 Mmiotrace traces Memory Mapped I/O access and is meant for 448 debugging and reverse engineering. It is called from the ioremap 449 implementation and works via page faults. Tracing is disabled by 450 default and can be enabled at run-time. 451 452 See Documentation/trace/mmiotrace.txt. 453 If you are not helping to develop drivers, say N. 454 455config MMIOTRACE_TEST 456 tristate "Test module for mmiotrace" 457 depends on MMIOTRACE && m 458 help 459 This is a dumb module for testing mmiotrace. It is very dangerous 460 as it will write garbage to IO memory starting at a given address. 461 However, it should be safe to use on e.g. unused portion of VRAM. 462 463 Say N, unless you absolutely know what you are doing. 464 465config RING_BUFFER_BENCHMARK 466 tristate "Ring buffer benchmark stress tester" 467 depends on RING_BUFFER 468 help 469 This option creates a test to stress the ring buffer and benchmark it. 470 It creates its own ring buffer such that it will not interfere with 471 any other users of the ring buffer (such as ftrace). It then creates 472 a producer and consumer that will run for 10 seconds and sleep for 473 10 seconds. Each interval it will print out the number of events 474 it recorded and give a rough estimate of how long each iteration took. 475 476 It does not disable interrupts or raise its priority, so it may be 477 affected by processes that are running. 478 479 If unsure, say N. 480 481endif # FTRACE 482 483endif # TRACING_SUPPORT 484 485