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 !ARCH_USES_GETTIMEOFFSET 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 !ARCH_USES_GETTIMEOFFSET 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 BLK_DEV_IO_TRACE 327 bool "Support for tracing block IO actions" 328 depends on SYSFS 329 depends on BLOCK 330 select RELAY 331 select DEBUG_FS 332 select TRACEPOINTS 333 select GENERIC_TRACER 334 select STACKTRACE 335 help 336 Say Y here if you want to be able to trace the block layer actions 337 on a given queue. Tracing allows you to see any traffic happening 338 on a block device queue. For more information (and the userspace 339 support tools needed), fetch the blktrace tools from: 340 341 git://git.kernel.dk/blktrace.git 342 343 Tracing also is possible using the ftrace interface, e.g.: 344 345 echo 1 > /sys/block/sda/sda1/trace/enable 346 echo blk > /sys/kernel/debug/tracing/current_tracer 347 cat /sys/kernel/debug/tracing/trace_pipe 348 349 If unsure, say N. 350 351config KPROBE_EVENT 352 depends on KPROBES 353 depends on HAVE_REGS_AND_STACK_ACCESS_API 354 bool "Enable kprobes-based dynamic events" 355 select TRACING 356 default y 357 help 358 This allows the user to add tracing events (similar to tracepoints) 359 on the fly via the ftrace interface. See 360 Documentation/trace/kprobetrace.txt for more details. 361 362 Those events can be inserted wherever kprobes can probe, and record 363 various register and memory values. 364 365 This option is also required by perf-probe subcommand of perf tools. 366 If you want to use perf tools, this option is strongly recommended. 367 368config DYNAMIC_FTRACE 369 bool "enable/disable ftrace tracepoints dynamically" 370 depends on FUNCTION_TRACER 371 depends on HAVE_DYNAMIC_FTRACE 372 default y 373 help 374 This option will modify all the calls to ftrace dynamically 375 (will patch them out of the binary image and replace them 376 with a No-Op instruction) as they are called. A table is 377 created to dynamically enable them again. 378 379 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but 380 otherwise has native performance as long as no tracing is active. 381 382 The changes to the code are done by a kernel thread that 383 wakes up once a second and checks to see if any ftrace calls 384 were made. If so, it runs stop_machine (stops all CPUS) 385 and modifies the code to jump over the call to ftrace. 386 387config FUNCTION_PROFILER 388 bool "Kernel function profiler" 389 depends on FUNCTION_TRACER 390 default n 391 help 392 This option enables the kernel function profiler. A file is created 393 in debugfs called function_profile_enabled which defaults to zero. 394 When a 1 is echoed into this file profiling begins, and when a 395 zero is entered, profiling stops. A "functions" file is created in 396 the trace_stats directory; this file shows the list of functions that 397 have been hit and their counters. 398 399 If in doubt, say N. 400 401config FTRACE_MCOUNT_RECORD 402 def_bool y 403 depends on DYNAMIC_FTRACE 404 depends on HAVE_FTRACE_MCOUNT_RECORD 405 406config FTRACE_SELFTEST 407 bool 408 409config FTRACE_STARTUP_TEST 410 bool "Perform a startup test on ftrace" 411 depends on GENERIC_TRACER 412 select FTRACE_SELFTEST 413 help 414 This option performs a series of startup tests on ftrace. On bootup 415 a series of tests are made to verify that the tracer is 416 functioning properly. It will do tests on all the configured 417 tracers of ftrace. 418 419config EVENT_TRACE_TEST_SYSCALLS 420 bool "Run selftest on syscall events" 421 depends on FTRACE_STARTUP_TEST 422 help 423 This option will also enable testing every syscall event. 424 It only enables the event and disables it and runs various loads 425 with the event enabled. This adds a bit more time for kernel boot 426 up since it runs this on every system call defined. 427 428 TBD - enable a way to actually call the syscalls as we test their 429 events 430 431config MMIOTRACE 432 bool "Memory mapped IO tracing" 433 depends on HAVE_MMIOTRACE_SUPPORT && PCI 434 select GENERIC_TRACER 435 help 436 Mmiotrace traces Memory Mapped I/O access and is meant for 437 debugging and reverse engineering. It is called from the ioremap 438 implementation and works via page faults. Tracing is disabled by 439 default and can be enabled at run-time. 440 441 See Documentation/trace/mmiotrace.txt. 442 If you are not helping to develop drivers, say N. 443 444config MMIOTRACE_TEST 445 tristate "Test module for mmiotrace" 446 depends on MMIOTRACE && m 447 help 448 This is a dumb module for testing mmiotrace. It is very dangerous 449 as it will write garbage to IO memory starting at a given address. 450 However, it should be safe to use on e.g. unused portion of VRAM. 451 452 Say N, unless you absolutely know what you are doing. 453 454config RING_BUFFER_BENCHMARK 455 tristate "Ring buffer benchmark stress tester" 456 depends on RING_BUFFER 457 help 458 This option creates a test to stress the ring buffer and benchmark it. 459 It creates its own ring buffer such that it will not interfere with 460 any other users of the ring buffer (such as ftrace). It then creates 461 a producer and consumer that will run for 10 seconds and sleep for 462 10 seconds. Each interval it will print out the number of events 463 it recorded and give a rough estimate of how long each iteration took. 464 465 It does not disable interrupts or raise its priority, so it may be 466 affected by processes that are running. 467 468 If unsure, say N. 469 470endif # FTRACE 471 472endif # TRACING_SUPPORT 473 474