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