1 # SPDX-License-Identifier: GPL-2.0-only <<
2 # 1 #
3 # Architectures that offer an FUNCTION_TRACER 2 # Architectures that offer an FUNCTION_TRACER implementation should
4 # select HAVE_FUNCTION_TRACER: 3 # select HAVE_FUNCTION_TRACER:
5 # 4 #
6 5
7 config USER_STACKTRACE_SUPPORT 6 config USER_STACKTRACE_SUPPORT
8 bool 7 bool
9 8
10 config NOP_TRACER 9 config NOP_TRACER
11 bool 10 bool
12 11
13 config HAVE_RETHOOK !! 12 config HAVE_FTRACE_NMI_ENTER
14 bool 13 bool
15 <<
16 config RETHOOK <<
17 bool <<
18 depends on HAVE_RETHOOK <<
19 help 14 help
20 Enable generic return hooking featur !! 15 See Documentation/trace/ftrace-design.txt
21 API, which will be used by other fun <<
22 features like fprobe and kprobes. <<
23 16
24 config HAVE_FUNCTION_TRACER 17 config HAVE_FUNCTION_TRACER
25 bool 18 bool
26 help 19 help
27 See Documentation/trace/ftrace-desig !! 20 See Documentation/trace/ftrace-design.txt
28 21
29 config HAVE_FUNCTION_GRAPH_TRACER 22 config HAVE_FUNCTION_GRAPH_TRACER
30 bool 23 bool
31 help 24 help
32 See Documentation/trace/ftrace-desig !! 25 See Documentation/trace/ftrace-design.txt
33 <<
34 config HAVE_FUNCTION_GRAPH_RETVAL <<
35 bool <<
36 26
37 config HAVE_DYNAMIC_FTRACE 27 config HAVE_DYNAMIC_FTRACE
38 bool 28 bool
39 help 29 help
40 See Documentation/trace/ftrace-desig !! 30 See Documentation/trace/ftrace-design.txt
41 31
42 config HAVE_DYNAMIC_FTRACE_WITH_REGS 32 config HAVE_DYNAMIC_FTRACE_WITH_REGS
43 bool 33 bool
44 34
45 config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS <<
46 bool <<
47 <<
48 config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS <<
49 bool <<
50 <<
51 config HAVE_DYNAMIC_FTRACE_WITH_ARGS <<
52 bool <<
53 help <<
54 If this is set, then arguments and st <<
55 the ftrace_regs passed into the funct <<
56 by default, even without setting the <<
57 This allows for use of ftrace_regs_ge <<
58 ftrace_regs_get_stack_pointer(). <<
59 <<
60 config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE <<
61 bool <<
62 help <<
63 If the architecture generates __patc <<
64 but does not want them included in t <<
65 <<
66 config HAVE_FTRACE_MCOUNT_RECORD 35 config HAVE_FTRACE_MCOUNT_RECORD
67 bool 36 bool
68 help 37 help
69 See Documentation/trace/ftrace-desig !! 38 See Documentation/trace/ftrace-design.txt
70 39
71 config HAVE_SYSCALL_TRACEPOINTS 40 config HAVE_SYSCALL_TRACEPOINTS
72 bool 41 bool
73 help 42 help
74 See Documentation/trace/ftrace-desig !! 43 See Documentation/trace/ftrace-design.txt
75 44
76 config HAVE_FENTRY 45 config HAVE_FENTRY
77 bool 46 bool
78 help 47 help
79 Arch supports the gcc options -pg wi 48 Arch supports the gcc options -pg with -mfentry
80 49
81 config HAVE_NOP_MCOUNT <<
82 bool <<
83 help <<
84 Arch supports the gcc options -pg wi <<
85 <<
86 config HAVE_OBJTOOL_MCOUNT <<
87 bool <<
88 help <<
89 Arch supports objtool --mcount <<
90 <<
91 config HAVE_OBJTOOL_NOP_MCOUNT <<
92 bool <<
93 help <<
94 Arch supports the objtool options -- <<
95 An architecture can select this if i <<
96 of ftrace locations. <<
97 <<
98 config HAVE_C_RECORDMCOUNT 50 config HAVE_C_RECORDMCOUNT
99 bool 51 bool
100 help 52 help
101 C version of recordmcount available? 53 C version of recordmcount available?
102 54
103 config HAVE_BUILDTIME_MCOUNT_SORT <<
104 bool <<
105 help <<
106 An architecture selects this if it so <<
107 at build time. <<
108 <<
109 config BUILDTIME_MCOUNT_SORT <<
110 bool <<
111 default y <<
112 depends on HAVE_BUILDTIME_MCOUNT_SORT & <<
113 help <<
114 Sort the mcount_loc section at build <<
115 <<
116 config TRACER_MAX_TRACE 55 config TRACER_MAX_TRACE
117 bool 56 bool
118 57
119 config TRACE_CLOCK 58 config TRACE_CLOCK
120 bool 59 bool
121 60
122 config RING_BUFFER 61 config RING_BUFFER
123 bool 62 bool
124 select TRACE_CLOCK 63 select TRACE_CLOCK
125 select IRQ_WORK 64 select IRQ_WORK
126 65
>> 66 config FTRACE_NMI_ENTER
>> 67 bool
>> 68 depends on HAVE_FTRACE_NMI_ENTER
>> 69 default y
>> 70
127 config EVENT_TRACING 71 config EVENT_TRACING
128 select CONTEXT_SWITCH_TRACER 72 select CONTEXT_SWITCH_TRACER
129 select GLOB !! 73 select GLOB
130 bool 74 bool
131 75
132 config CONTEXT_SWITCH_TRACER 76 config CONTEXT_SWITCH_TRACER
133 bool 77 bool
134 78
135 config RING_BUFFER_ALLOW_SWAP 79 config RING_BUFFER_ALLOW_SWAP
136 bool 80 bool
137 help 81 help
138 Allow the use of ring_buffer_swap_cpu 82 Allow the use of ring_buffer_swap_cpu.
139 Adds a very slight overhead to tracin 83 Adds a very slight overhead to tracing when enabled.
140 84
141 config PREEMPTIRQ_TRACEPOINTS <<
142 bool <<
143 depends on TRACE_PREEMPT_TOGGLE || TRA <<
144 select TRACING <<
145 default y <<
146 help <<
147 Create preempt/irq toggle tracepoint <<
148 of the kernel can use them to genera <<
149 <<
150 # All tracer options should select GENERIC_TRA 85 # All tracer options should select GENERIC_TRACER. For those options that are
151 # enabled by all tracers (context switch and e 86 # enabled by all tracers (context switch and event tracer) they select TRACING.
152 # This allows those options to appear when no 87 # This allows those options to appear when no other tracer is selected. But the
153 # options do not appear when something else se 88 # options do not appear when something else selects it. We need the two options
154 # GENERIC_TRACER and TRACING to avoid circular 89 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
155 # hiding of the automatic options. 90 # hiding of the automatic options.
156 91
157 config TRACING 92 config TRACING
158 bool 93 bool
>> 94 select DEBUG_FS
159 select RING_BUFFER 95 select RING_BUFFER
160 select STACKTRACE if STACKTRACE_SUPPOR 96 select STACKTRACE if STACKTRACE_SUPPORT
161 select TRACEPOINTS 97 select TRACEPOINTS
162 select NOP_TRACER 98 select NOP_TRACER
163 select BINARY_PRINTF 99 select BINARY_PRINTF
164 select EVENT_TRACING 100 select EVENT_TRACING
165 select TRACE_CLOCK 101 select TRACE_CLOCK
166 select NEED_TASKS_RCU <<
167 102
168 config GENERIC_TRACER 103 config GENERIC_TRACER
169 bool 104 bool
170 select TRACING 105 select TRACING
171 106
172 # 107 #
173 # Minimum requirements an architecture has to 108 # Minimum requirements an architecture has to meet for us to
174 # be able to offer generic tracing facilities: 109 # be able to offer generic tracing facilities:
175 # 110 #
176 config TRACING_SUPPORT 111 config TRACING_SUPPORT
177 bool 112 bool
178 depends on TRACE_IRQFLAGS_SUPPORT !! 113 # PPC32 has no irqflags tracing support, but it can use most of the
>> 114 # tracers anyway, they were tested to build and work. Note that new
>> 115 # exceptions to this list aren't welcomed, better implement the
>> 116 # irqflags tracing for your architecture.
>> 117 depends on TRACE_IRQFLAGS_SUPPORT || PPC32
179 depends on STACKTRACE_SUPPORT 118 depends on STACKTRACE_SUPPORT
180 default y 119 default y
181 120
>> 121 if TRACING_SUPPORT
>> 122
182 menuconfig FTRACE 123 menuconfig FTRACE
183 bool "Tracers" 124 bool "Tracers"
184 depends on TRACING_SUPPORT <<
185 default y if DEBUG_KERNEL 125 default y if DEBUG_KERNEL
186 help 126 help
187 Enable the kernel tracing infrastruc 127 Enable the kernel tracing infrastructure.
188 128
189 if FTRACE 129 if FTRACE
190 130
191 config BOOTTIME_TRACING <<
192 bool "Boot-time Tracing support" <<
193 depends on TRACING <<
194 select BOOT_CONFIG <<
195 help <<
196 Enable developer to setup ftrace sub <<
197 kernel cmdline at boot time for debu <<
198 initialization and boot process. <<
199 <<
200 config FUNCTION_TRACER 131 config FUNCTION_TRACER
201 bool "Kernel Function Tracer" 132 bool "Kernel Function Tracer"
202 depends on HAVE_FUNCTION_TRACER 133 depends on HAVE_FUNCTION_TRACER
203 select KALLSYMS 134 select KALLSYMS
204 select GENERIC_TRACER 135 select GENERIC_TRACER
205 select CONTEXT_SWITCH_TRACER 136 select CONTEXT_SWITCH_TRACER
206 select GLOB 137 select GLOB
207 select NEED_TASKS_RCU !! 138 select TASKS_RCU if PREEMPT
208 select TASKS_RUDE_RCU <<
209 help 139 help
210 Enable the kernel to trace every ker 140 Enable the kernel to trace every kernel function. This is done
211 by using a compiler feature to inser 141 by using a compiler feature to insert a small, 5-byte No-Operation
212 instruction at the beginning of ever 142 instruction at the beginning of every kernel function, which NOP
213 sequence is then dynamically patched 143 sequence is then dynamically patched into a tracer call when
214 tracing is enabled by the administra 144 tracing is enabled by the administrator. If it's runtime disabled
215 (the bootup default), then the overh 145 (the bootup default), then the overhead of the instructions is very
216 small and not measurable even in mic !! 146 small and not measurable even in micro-benchmarks.
217 x86, but may have impact on other ar <<
218 147
219 config FUNCTION_GRAPH_TRACER 148 config FUNCTION_GRAPH_TRACER
220 bool "Kernel Function Graph Tracer" 149 bool "Kernel Function Graph Tracer"
221 depends on HAVE_FUNCTION_GRAPH_TRACER 150 depends on HAVE_FUNCTION_GRAPH_TRACER
222 depends on FUNCTION_TRACER 151 depends on FUNCTION_TRACER
223 depends on !X86_32 || !CC_OPTIMIZE_FOR 152 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
224 default y 153 default y
225 help 154 help
226 Enable the kernel to trace a functio 155 Enable the kernel to trace a function at both its return
227 and its entry. 156 and its entry.
228 Its first purpose is to trace the du 157 Its first purpose is to trace the duration of functions and
229 draw a call graph for each thread wi 158 draw a call graph for each thread with some information like
230 the return value. This is done by se 159 the return value. This is done by setting the current return
231 address on the current task structur 160 address on the current task structure into a stack of calls.
232 161
233 config FUNCTION_GRAPH_RETVAL <<
234 bool "Kernel Function Graph Return Val <<
235 depends on HAVE_FUNCTION_GRAPH_RETVAL <<
236 depends on FUNCTION_GRAPH_TRACER <<
237 default n <<
238 help <<
239 Support recording and printing the f <<
240 using function graph tracer. It can <<
241 that return errors. This feature is <<
242 enable it via the trace option funcg <<
243 See Documentation/trace/ftrace.rst <<
244 <<
245 config DYNAMIC_FTRACE <<
246 bool "enable/disable function tracing <<
247 depends on FUNCTION_TRACER <<
248 depends on HAVE_DYNAMIC_FTRACE <<
249 default y <<
250 help <<
251 This option will modify all the call <<
252 dynamically (will patch them out of <<
253 replace them with a No-Op instructio <<
254 compile time, a table is made of all <<
255 can function trace, and this table i <<
256 image. When this is enabled, functio <<
257 enabled, and the functions not enabl <<
258 performance of the system. <<
259 <<
260 See the files in /sys/kernel/tracing <<
261 available_filter_functions <<
262 set_ftrace_filter <<
263 set_ftrace_notrace <<
264 <<
265 This way a CONFIG_FUNCTION_TRACER ke <<
266 otherwise has native performance as <<
267 <<
268 config DYNAMIC_FTRACE_WITH_REGS <<
269 def_bool y <<
270 depends on DYNAMIC_FTRACE <<
271 depends on HAVE_DYNAMIC_FTRACE_WITH_RE <<
272 <<
273 config DYNAMIC_FTRACE_WITH_DIRECT_CALLS <<
274 def_bool y <<
275 depends on DYNAMIC_FTRACE_WITH_REGS || <<
276 depends on HAVE_DYNAMIC_FTRACE_WITH_DI <<
277 <<
278 config DYNAMIC_FTRACE_WITH_CALL_OPS <<
279 def_bool y <<
280 depends on HAVE_DYNAMIC_FTRACE_WITH_CA <<
281 <<
282 config DYNAMIC_FTRACE_WITH_ARGS <<
283 def_bool y <<
284 depends on DYNAMIC_FTRACE <<
285 depends on HAVE_DYNAMIC_FTRACE_WITH_AR <<
286 <<
287 config FPROBE <<
288 bool "Kernel Function Probe (fprobe)" <<
289 depends on FUNCTION_TRACER <<
290 depends on DYNAMIC_FTRACE_WITH_REGS <<
291 depends on HAVE_RETHOOK <<
292 select RETHOOK <<
293 default n <<
294 help <<
295 This option enables kernel function <<
296 The fprobe is similar to kprobes, bu <<
297 entries and exits. This also can pro <<
298 fprobe. <<
299 <<
300 If unsure, say N. <<
301 <<
302 config FUNCTION_PROFILER <<
303 bool "Kernel function profiler" <<
304 depends on FUNCTION_TRACER <<
305 default n <<
306 help <<
307 This option enables the kernel funct <<
308 in debugfs called function_profile_e <<
309 When a 1 is echoed into this file pr <<
310 zero is entered, profiling stops. A <<
311 the trace_stat directory; this file <<
312 have been hit and their counters. <<
313 <<
314 If in doubt, say N. <<
315 <<
316 config STACK_TRACER <<
317 bool "Trace max stack" <<
318 depends on HAVE_FUNCTION_TRACER <<
319 select FUNCTION_TRACER <<
320 select STACKTRACE <<
321 select KALLSYMS <<
322 help <<
323 This special tracer records the maxi <<
324 kernel and displays it in /sys/kerne <<
325 <<
326 This tracer works by hooking into ev <<
327 kernel executes, and keeping a maxim <<
328 stack-trace saved. If this is confi <<
329 then it will not have any overhead w <<
330 is disabled. <<
331 <<
332 To enable the stack tracer on bootup <<
333 on the kernel command line. <<
334 <<
335 The stack tracer can also be enabled <<
336 sysctl kernel.stack_tracer_enabled <<
337 <<
338 Say N if unsure. <<
339 <<
340 config TRACE_PREEMPT_TOGGLE <<
341 bool <<
342 help <<
343 Enables hooks which will be called w <<
344 and last enabled. <<
345 162
346 config IRQSOFF_TRACER 163 config IRQSOFF_TRACER
347 bool "Interrupts-off Latency Tracer" 164 bool "Interrupts-off Latency Tracer"
348 default n 165 default n
349 depends on TRACE_IRQFLAGS_SUPPORT 166 depends on TRACE_IRQFLAGS_SUPPORT
>> 167 depends on !ARCH_USES_GETTIMEOFFSET
350 select TRACE_IRQFLAGS 168 select TRACE_IRQFLAGS
351 select GENERIC_TRACER 169 select GENERIC_TRACER
352 select TRACER_MAX_TRACE 170 select TRACER_MAX_TRACE
353 select RING_BUFFER_ALLOW_SWAP 171 select RING_BUFFER_ALLOW_SWAP
354 select TRACER_SNAPSHOT 172 select TRACER_SNAPSHOT
355 select TRACER_SNAPSHOT_PER_CPU_SWAP 173 select TRACER_SNAPSHOT_PER_CPU_SWAP
356 help 174 help
357 This option measures the time spent 175 This option measures the time spent in irqs-off critical
358 sections, with microsecond accuracy. 176 sections, with microsecond accuracy.
359 177
360 The default measurement method is a 178 The default measurement method is a maximum search, which is
361 disabled by default and can be runti 179 disabled by default and can be runtime (re-)started
362 via: 180 via:
363 181
364 echo 0 > /sys/kernel/tracing/tra !! 182 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
365 183
366 (Note that kernel size and overhead 184 (Note that kernel size and overhead increase with this option
367 enabled. This option and the preempt 185 enabled. This option and the preempt-off timing option can be
368 used together or separately.) 186 used together or separately.)
369 187
370 config PREEMPT_TRACER 188 config PREEMPT_TRACER
371 bool "Preemption-off Latency Tracer" 189 bool "Preemption-off Latency Tracer"
372 default n 190 default n
373 depends on PREEMPTION !! 191 depends on !ARCH_USES_GETTIMEOFFSET
>> 192 depends on PREEMPT
374 select GENERIC_TRACER 193 select GENERIC_TRACER
375 select TRACER_MAX_TRACE 194 select TRACER_MAX_TRACE
376 select RING_BUFFER_ALLOW_SWAP 195 select RING_BUFFER_ALLOW_SWAP
377 select TRACER_SNAPSHOT 196 select TRACER_SNAPSHOT
378 select TRACER_SNAPSHOT_PER_CPU_SWAP 197 select TRACER_SNAPSHOT_PER_CPU_SWAP
379 select TRACE_PREEMPT_TOGGLE <<
380 help 198 help
381 This option measures the time spent 199 This option measures the time spent in preemption-off critical
382 sections, with microsecond accuracy. 200 sections, with microsecond accuracy.
383 201
384 The default measurement method is a 202 The default measurement method is a maximum search, which is
385 disabled by default and can be runti 203 disabled by default and can be runtime (re-)started
386 via: 204 via:
387 205
388 echo 0 > /sys/kernel/tracing/tra !! 206 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
389 207
390 (Note that kernel size and overhead 208 (Note that kernel size and overhead increase with this option
391 enabled. This option and the irqs-of 209 enabled. This option and the irqs-off timing option can be
392 used together or separately.) 210 used together or separately.)
393 211
394 config SCHED_TRACER 212 config SCHED_TRACER
395 bool "Scheduling Latency Tracer" 213 bool "Scheduling Latency Tracer"
396 select GENERIC_TRACER 214 select GENERIC_TRACER
397 select CONTEXT_SWITCH_TRACER 215 select CONTEXT_SWITCH_TRACER
398 select TRACER_MAX_TRACE 216 select TRACER_MAX_TRACE
399 select TRACER_SNAPSHOT 217 select TRACER_SNAPSHOT
400 help 218 help
401 This tracer tracks the latency of th 219 This tracer tracks the latency of the highest priority task
402 to be scheduled in, starting from th 220 to be scheduled in, starting from the point it has woken up.
403 221
404 config HWLAT_TRACER 222 config HWLAT_TRACER
405 bool "Tracer to detect hardware latenc 223 bool "Tracer to detect hardware latencies (like SMIs)"
406 select GENERIC_TRACER 224 select GENERIC_TRACER
407 select TRACER_MAX_TRACE <<
408 help 225 help
409 This tracer, when enabled will create 226 This tracer, when enabled will create one or more kernel threads,
410 depending on what the cpumask file is !! 227 depening on what the cpumask file is set to, which each thread
411 spinning in a loop looking for interr 228 spinning in a loop looking for interruptions caused by
412 something other than the kernel. For 229 something other than the kernel. For example, if a
413 System Management Interrupt (SMI) tak 230 System Management Interrupt (SMI) takes a noticeable amount of
414 time, this tracer will detect it. Thi 231 time, this tracer will detect it. This is useful for testing
415 if a system is reliable for Real Time 232 if a system is reliable for Real Time tasks.
416 233
417 Some files are created in the tracing 234 Some files are created in the tracing directory when this
418 is enabled: 235 is enabled:
419 236
420 hwlat_detector/width - time in us 237 hwlat_detector/width - time in usecs for how long to spin for
421 hwlat_detector/window - time in us 238 hwlat_detector/window - time in usecs between the start of each
422 iteration 239 iteration
423 240
424 A kernel thread is created that will 241 A kernel thread is created that will spin with interrupts disabled
425 for "width" microseconds in every "wi !! 242 for "width" microseconds in every "widow" cycle. It will not spin
426 for "window - width" microseconds, wh 243 for "window - width" microseconds, where the system can
427 continue to operate. 244 continue to operate.
428 245
429 The output will appear in the trace a 246 The output will appear in the trace and trace_pipe files.
430 247
431 When the tracer is not running, it ha 248 When the tracer is not running, it has no affect on the system,
432 but when it is running, it can cause 249 but when it is running, it can cause the system to be
433 periodically non responsive. Do not r 250 periodically non responsive. Do not run this tracer on a
434 production system. 251 production system.
435 252
436 To enable this tracer, echo in "hwlat 253 To enable this tracer, echo in "hwlat" into the current_tracer
437 file. Every time a latency is greater 254 file. Every time a latency is greater than tracing_thresh, it will
438 be recorded into the ring buffer. 255 be recorded into the ring buffer.
439 256
440 config OSNOISE_TRACER <<
441 bool "OS Noise tracer" <<
442 select GENERIC_TRACER <<
443 select TRACER_MAX_TRACE <<
444 help <<
445 In the context of high-performance c <<
446 System Noise (osnoise) refers to the <<
447 application due to activities inside <<
448 context of Linux, NMIs, IRQs, SoftIR <<
449 can cause noise to the system. Moreo <<
450 also cause noise, for example, via S <<
451 <<
452 The osnoise tracer leverages the hwl <<
453 loop with preemption, SoftIRQs and I <<
454 the sources of osnoise during its ex <<
455 note of the entry and exit point of <<
456 increasing a per-cpu interference co <<
457 counter for each source of interfere <<
458 NMI, IRQs, SoftIRQs, and threads is <<
459 observes these interferences' entry <<
460 without any interference from the op <<
461 hardware noise counter increases, po <<
462 noise. In this way, osnoise can acco <<
463 interference. At the end of the peri <<
464 the sum of all noise, the max single <<
465 available for the thread, and the co <<
466 <<
467 In addition to the tracer, a set of <<
468 facilitate the identification of the <<
469 <<
470 The output will appear in the trace <<
471 <<
472 To enable this tracer, echo in "osno <<
473 file. <<
474 <<
475 config TIMERLAT_TRACER <<
476 bool "Timerlat tracer" <<
477 select OSNOISE_TRACER <<
478 select GENERIC_TRACER <<
479 help <<
480 The timerlat tracer aims to help the <<
481 to find sources of wakeup latencies <<
482 <<
483 The tracer creates a per-cpu kernel <<
484 The tracer thread sets a periodic ti <<
485 to sleep waiting for the timer to fi <<
486 then computes a wakeup latency value <<
487 the current time and the absolute ti <<
488 to expire. <<
489 <<
490 The tracer prints two lines at every <<
491 timer latency observed at the hardir <<
492 activation of the thread. The second <<
493 by the thread, which is the same lev <<
494 ACTIVATION ID field serves to relate <<
495 respective thread execution. <<
496 <<
497 The tracer is build on top of osnois <<
498 events can be used to trace the sour <<
499 IRQs and other threads. It also enab <<
500 stacktrace at the IRQ context, which <<
501 path that can cause thread delay. <<
502 <<
503 config MMIOTRACE <<
504 bool "Memory mapped IO tracing" <<
505 depends on HAVE_MMIOTRACE_SUPPORT && P <<
506 select GENERIC_TRACER <<
507 help <<
508 Mmiotrace traces Memory Mapped I/O a <<
509 debugging and reverse engineering. I <<
510 implementation and works via page fa <<
511 default and can be enabled at run-ti <<
512 <<
513 See Documentation/trace/mmiotrace.rs <<
514 If you are not helping to develop dr <<
515 <<
516 config ENABLE_DEFAULT_TRACERS 257 config ENABLE_DEFAULT_TRACERS
517 bool "Trace process context switches a 258 bool "Trace process context switches and events"
518 depends on !GENERIC_TRACER 259 depends on !GENERIC_TRACER
519 select TRACING 260 select TRACING
520 help 261 help
521 This tracer hooks to various trace p 262 This tracer hooks to various trace points in the kernel,
522 allowing the user to pick and choose 263 allowing the user to pick and choose which trace point they
523 want to trace. It also includes the 264 want to trace. It also includes the sched_switch tracer plugin.
524 265
525 config FTRACE_SYSCALLS 266 config FTRACE_SYSCALLS
526 bool "Trace syscalls" 267 bool "Trace syscalls"
527 depends on HAVE_SYSCALL_TRACEPOINTS 268 depends on HAVE_SYSCALL_TRACEPOINTS
528 select GENERIC_TRACER 269 select GENERIC_TRACER
529 select KALLSYMS 270 select KALLSYMS
530 help 271 help
531 Basic tracer to catch the syscall en 272 Basic tracer to catch the syscall entry and exit events.
532 273
533 config TRACER_SNAPSHOT 274 config TRACER_SNAPSHOT
534 bool "Create a snapshot trace buffer" 275 bool "Create a snapshot trace buffer"
535 select TRACER_MAX_TRACE 276 select TRACER_MAX_TRACE
536 help 277 help
537 Allow tracing users to take snapshot 278 Allow tracing users to take snapshot of the current buffer using the
538 ftrace interface, e.g.: 279 ftrace interface, e.g.:
539 280
540 echo 1 > /sys/kernel/tracing/sna !! 281 echo 1 > /sys/kernel/debug/tracing/snapshot
541 cat snapshot 282 cat snapshot
542 283
543 config TRACER_SNAPSHOT_PER_CPU_SWAP 284 config TRACER_SNAPSHOT_PER_CPU_SWAP
544 bool "Allow snapshot to swap per CPU" !! 285 bool "Allow snapshot to swap per CPU"
545 depends on TRACER_SNAPSHOT 286 depends on TRACER_SNAPSHOT
546 select RING_BUFFER_ALLOW_SWAP 287 select RING_BUFFER_ALLOW_SWAP
547 help 288 help
548 Allow doing a snapshot of a single C 289 Allow doing a snapshot of a single CPU buffer instead of a
549 full swap (all buffers). If this is 290 full swap (all buffers). If this is set, then the following is
550 allowed: 291 allowed:
551 292
552 echo 1 > /sys/kernel/tracing/per !! 293 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
553 294
554 After which, only the tracing buffer 295 After which, only the tracing buffer for CPU 2 was swapped with
555 the main tracing buffer, and the oth 296 the main tracing buffer, and the other CPU buffers remain the same.
556 297
557 When this is enabled, this adds a li 298 When this is enabled, this adds a little more overhead to the
558 trace recording, as it needs to add 299 trace recording, as it needs to add some checks to synchronize
559 recording with swaps. But this does 300 recording with swaps. But this does not affect the performance
560 of the overall system. This is enabl 301 of the overall system. This is enabled by default when the preempt
561 or irq latency tracers are enabled, 302 or irq latency tracers are enabled, as those need to swap as well
562 and already adds the overhead (plus 303 and already adds the overhead (plus a lot more).
563 304
564 config TRACE_BRANCH_PROFILING 305 config TRACE_BRANCH_PROFILING
565 bool 306 bool
566 select GENERIC_TRACER 307 select GENERIC_TRACER
567 308
568 choice 309 choice
569 prompt "Branch Profiling" 310 prompt "Branch Profiling"
570 default BRANCH_PROFILE_NONE 311 default BRANCH_PROFILE_NONE
571 help 312 help
572 The branch profiling is a software pr 313 The branch profiling is a software profiler. It will add hooks
573 into the C conditionals to test which 314 into the C conditionals to test which path a branch takes.
574 315
575 The likely/unlikely profiler only loo 316 The likely/unlikely profiler only looks at the conditions that
576 are annotated with a likely or unlike 317 are annotated with a likely or unlikely macro.
577 318
578 The "all branch" profiler will profil 319 The "all branch" profiler will profile every if-statement in the
579 kernel. This profiler will also enabl 320 kernel. This profiler will also enable the likely/unlikely
580 profiler. 321 profiler.
581 322
582 Either of the above profilers adds a 323 Either of the above profilers adds a bit of overhead to the system.
583 If unsure, choose "No branch profilin 324 If unsure, choose "No branch profiling".
584 325
585 config BRANCH_PROFILE_NONE 326 config BRANCH_PROFILE_NONE
586 bool "No branch profiling" 327 bool "No branch profiling"
587 help 328 help
588 No branch profiling. Branch profilin 329 No branch profiling. Branch profiling adds a bit of overhead.
589 Only enable it if you want to analys 330 Only enable it if you want to analyse the branching behavior.
590 Otherwise keep it disabled. 331 Otherwise keep it disabled.
591 332
592 config PROFILE_ANNOTATED_BRANCHES 333 config PROFILE_ANNOTATED_BRANCHES
593 bool "Trace likely/unlikely profiler" 334 bool "Trace likely/unlikely profiler"
594 select TRACE_BRANCH_PROFILING 335 select TRACE_BRANCH_PROFILING
595 help 336 help
596 This tracer profiles all likely and 337 This tracer profiles all likely and unlikely macros
597 in the kernel. It will display the r 338 in the kernel. It will display the results in:
598 339
599 /sys/kernel/tracing/trace_stat/branc !! 340 /sys/kernel/debug/tracing/trace_stat/branch_annotated
600 341
601 Note: this will add a significant ov 342 Note: this will add a significant overhead; only turn this
602 on if you need to profile the system 343 on if you need to profile the system's use of these macros.
603 344
604 config PROFILE_ALL_BRANCHES 345 config PROFILE_ALL_BRANCHES
605 bool "Profile all if conditionals" if !! 346 bool "Profile all if conditionals"
606 select TRACE_BRANCH_PROFILING 347 select TRACE_BRANCH_PROFILING
607 help 348 help
608 This tracer profiles all branch cond 349 This tracer profiles all branch conditions. Every if ()
609 taken in the kernel is recorded whet 350 taken in the kernel is recorded whether it hit or miss.
610 The results will be displayed in: 351 The results will be displayed in:
611 352
612 /sys/kernel/tracing/trace_stat/branc !! 353 /sys/kernel/debug/tracing/trace_stat/branch_all
613 354
614 This option also enables the likely/ 355 This option also enables the likely/unlikely profiler.
615 356
616 This configuration, when enabled, wi 357 This configuration, when enabled, will impose a great overhead
617 on the system. This should only be e 358 on the system. This should only be enabled when the system
618 is to be analyzed in much detail. 359 is to be analyzed in much detail.
619 endchoice 360 endchoice
620 361
621 config TRACING_BRANCHES 362 config TRACING_BRANCHES
622 bool 363 bool
623 help 364 help
624 Selected by tracers that will trace 365 Selected by tracers that will trace the likely and unlikely
625 conditions. This prevents the tracer 366 conditions. This prevents the tracers themselves from being
626 profiled. Profiling the tracing infr 367 profiled. Profiling the tracing infrastructure can only happen
627 when the likelys and unlikelys are n 368 when the likelys and unlikelys are not being traced.
628 369
629 config BRANCH_TRACER 370 config BRANCH_TRACER
630 bool "Trace likely/unlikely instances" 371 bool "Trace likely/unlikely instances"
631 depends on TRACE_BRANCH_PROFILING 372 depends on TRACE_BRANCH_PROFILING
632 select TRACING_BRANCHES 373 select TRACING_BRANCHES
633 help 374 help
634 This traces the events of likely and 375 This traces the events of likely and unlikely condition
635 calls in the kernel. The difference 376 calls in the kernel. The difference between this and the
636 "Trace likely/unlikely profiler" is 377 "Trace likely/unlikely profiler" is that this is not a
637 histogram of the callers, but actual 378 histogram of the callers, but actually places the calling
638 events into a running trace buffer t 379 events into a running trace buffer to see when and where the
639 events happened, as well as their re 380 events happened, as well as their results.
640 381
641 Say N if unsure. 382 Say N if unsure.
642 383
>> 384 config STACK_TRACER
>> 385 bool "Trace max stack"
>> 386 depends on HAVE_FUNCTION_TRACER
>> 387 select FUNCTION_TRACER
>> 388 select STACKTRACE
>> 389 select KALLSYMS
>> 390 help
>> 391 This special tracer records the maximum stack footprint of the
>> 392 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
>> 393
>> 394 This tracer works by hooking into every function call that the
>> 395 kernel executes, and keeping a maximum stack depth value and
>> 396 stack-trace saved. If this is configured with DYNAMIC_FTRACE
>> 397 then it will not have any overhead while the stack tracer
>> 398 is disabled.
>> 399
>> 400 To enable the stack tracer on bootup, pass in 'stacktrace'
>> 401 on the kernel command line.
>> 402
>> 403 The stack tracer can also be enabled or disabled via the
>> 404 sysctl kernel.stack_tracer_enabled
>> 405
>> 406 Say N if unsure.
>> 407
643 config BLK_DEV_IO_TRACE 408 config BLK_DEV_IO_TRACE
644 bool "Support for tracing block IO act 409 bool "Support for tracing block IO actions"
645 depends on SYSFS 410 depends on SYSFS
646 depends on BLOCK 411 depends on BLOCK
647 select RELAY 412 select RELAY
648 select DEBUG_FS 413 select DEBUG_FS
649 select TRACEPOINTS 414 select TRACEPOINTS
650 select GENERIC_TRACER 415 select GENERIC_TRACER
651 select STACKTRACE 416 select STACKTRACE
652 help 417 help
653 Say Y here if you want to be able to 418 Say Y here if you want to be able to trace the block layer actions
654 on a given queue. Tracing allows you 419 on a given queue. Tracing allows you to see any traffic happening
655 on a block device queue. For more in 420 on a block device queue. For more information (and the userspace
656 support tools needed), fetch the blk 421 support tools needed), fetch the blktrace tools from:
657 422
658 git://git.kernel.dk/blktrace.git 423 git://git.kernel.dk/blktrace.git
659 424
660 Tracing also is possible using the f 425 Tracing also is possible using the ftrace interface, e.g.:
661 426
662 echo 1 > /sys/block/sda/sda1/trace 427 echo 1 > /sys/block/sda/sda1/trace/enable
663 echo blk > /sys/kernel/tracing/cur !! 428 echo blk > /sys/kernel/debug/tracing/current_tracer
664 cat /sys/kernel/tracing/trace_pipe !! 429 cat /sys/kernel/debug/tracing/trace_pipe
665 430
666 If unsure, say N. 431 If unsure, say N.
667 432
668 config FPROBE_EVENTS <<
669 depends on FPROBE <<
670 depends on HAVE_REGS_AND_STACK_ACCESS_ <<
671 bool "Enable fprobe-based dynamic even <<
672 select TRACING <<
673 select PROBE_EVENTS <<
674 select DYNAMIC_EVENTS <<
675 default y <<
676 help <<
677 This allows user to add tracing even <<
678 exit via ftrace interface. The synta <<
679 and the kprobe events on function en <<
680 transparently converted to this fpro <<
681 <<
682 config PROBE_EVENTS_BTF_ARGS <<
683 depends on HAVE_FUNCTION_ARG_ACCESS_AP <<
684 depends on FPROBE_EVENTS || KPROBE_EVE <<
685 depends on DEBUG_INFO_BTF && BPF_SYSCA <<
686 bool "Support BTF function arguments f <<
687 default y <<
688 help <<
689 The user can specify the arguments o <<
690 of the arguments of the probed funct <<
691 kernel function entry or a tracepoin <<
692 This is available only if BTF (BPF T <<
693 <<
694 config KPROBE_EVENTS 433 config KPROBE_EVENTS
695 depends on KPROBES 434 depends on KPROBES
696 depends on HAVE_REGS_AND_STACK_ACCESS_ 435 depends on HAVE_REGS_AND_STACK_ACCESS_API
697 bool "Enable kprobes-based dynamic eve 436 bool "Enable kprobes-based dynamic events"
698 select TRACING 437 select TRACING
699 select PROBE_EVENTS 438 select PROBE_EVENTS
700 select DYNAMIC_EVENTS <<
701 default y 439 default y
702 help 440 help
703 This allows the user to add tracing 441 This allows the user to add tracing events (similar to tracepoints)
704 on the fly via the ftrace interface. 442 on the fly via the ftrace interface. See
705 Documentation/trace/kprobetrace.rst !! 443 Documentation/trace/kprobetrace.txt for more details.
706 444
707 Those events can be inserted whereve 445 Those events can be inserted wherever kprobes can probe, and record
708 various register and memory values. 446 various register and memory values.
709 447
710 This option is also required by perf 448 This option is also required by perf-probe subcommand of perf tools.
711 If you want to use perf tools, this 449 If you want to use perf tools, this option is strongly recommended.
712 450
713 config KPROBE_EVENTS_ON_NOTRACE <<
714 bool "Do NOT protect notrace function <<
715 depends on KPROBE_EVENTS <<
716 depends on DYNAMIC_FTRACE <<
717 default n <<
718 help <<
719 This is only for the developers who <<
720 using kprobe events. <<
721 <<
722 If kprobes can use ftrace instead of <<
723 functions are protected from kprobe- <<
724 recursion or any unexpected executio <<
725 crash. <<
726 <<
727 This option disables such protection <<
728 events on ftrace functions for debug <<
729 Note that this might let you shoot y <<
730 <<
731 If unsure, say N. <<
732 <<
733 config UPROBE_EVENTS 451 config UPROBE_EVENTS
734 bool "Enable uprobes-based dynamic eve 452 bool "Enable uprobes-based dynamic events"
735 depends on ARCH_SUPPORTS_UPROBES 453 depends on ARCH_SUPPORTS_UPROBES
736 depends on MMU 454 depends on MMU
737 depends on PERF_EVENTS 455 depends on PERF_EVENTS
738 select UPROBES 456 select UPROBES
739 select PROBE_EVENTS 457 select PROBE_EVENTS
740 select DYNAMIC_EVENTS <<
741 select TRACING 458 select TRACING
742 default y 459 default y
743 help 460 help
744 This allows the user to add tracing 461 This allows the user to add tracing events on top of userspace
745 dynamic events (similar to tracepoin 462 dynamic events (similar to tracepoints) on the fly via the trace
746 events interface. Those events can b 463 events interface. Those events can be inserted wherever uprobes
747 can probe, and record various regist 464 can probe, and record various registers.
748 This option is required if you plan 465 This option is required if you plan to use perf-probe subcommand
749 of perf tools on user space applicat 466 of perf tools on user space applications.
750 467
751 config BPF_EVENTS 468 config BPF_EVENTS
752 depends on BPF_SYSCALL 469 depends on BPF_SYSCALL
753 depends on (KPROBE_EVENTS || UPROBE_EV 470 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
754 bool 471 bool
755 default y 472 default y
756 help 473 help
757 This allows the user to attach BPF p !! 474 This allows the user to attach BPF programs to kprobe events.
758 tracepoint events. <<
759 <<
760 config DYNAMIC_EVENTS <<
761 def_bool n <<
762 475
763 config PROBE_EVENTS 476 config PROBE_EVENTS
764 def_bool n 477 def_bool n
765 478
766 config BPF_KPROBE_OVERRIDE !! 479 config DYNAMIC_FTRACE
767 bool "Enable BPF programs to override !! 480 bool "enable/disable function tracing dynamically"
768 depends on BPF_EVENTS !! 481 depends on FUNCTION_TRACER
769 depends on FUNCTION_ERROR_INJECTION !! 482 depends on HAVE_DYNAMIC_FTRACE
>> 483 default y
>> 484 help
>> 485 This option will modify all the calls to function tracing
>> 486 dynamically (will patch them out of the binary image and
>> 487 replace them with a No-Op instruction) on boot up. During
>> 488 compile time, a table is made of all the locations that ftrace
>> 489 can function trace, and this table is linked into the kernel
>> 490 image. When this is enabled, functions can be individually
>> 491 enabled, and the functions not enabled will not affect
>> 492 performance of the system.
>> 493
>> 494 See the files in /sys/kernel/debug/tracing:
>> 495 available_filter_functions
>> 496 set_ftrace_filter
>> 497 set_ftrace_notrace
>> 498
>> 499 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
>> 500 otherwise has native performance as long as no tracing is active.
>> 501
>> 502 config DYNAMIC_FTRACE_WITH_REGS
>> 503 def_bool y
>> 504 depends on DYNAMIC_FTRACE
>> 505 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
>> 506
>> 507 config FUNCTION_PROFILER
>> 508 bool "Kernel function profiler"
>> 509 depends on FUNCTION_TRACER
770 default n 510 default n
771 help 511 help
772 Allows BPF to override the execution !! 512 This option enables the kernel function profiler. A file is created
773 set a different return value. This i !! 513 in debugfs called function_profile_enabled which defaults to zero.
>> 514 When a 1 is echoed into this file profiling begins, and when a
>> 515 zero is entered, profiling stops. A "functions" file is created in
>> 516 the trace_stats directory; this file shows the list of functions that
>> 517 have been hit and their counters.
>> 518
>> 519 If in doubt, say N.
774 520
775 config FTRACE_MCOUNT_RECORD 521 config FTRACE_MCOUNT_RECORD
776 def_bool y 522 def_bool y
777 depends on DYNAMIC_FTRACE 523 depends on DYNAMIC_FTRACE
778 depends on HAVE_FTRACE_MCOUNT_RECORD 524 depends on HAVE_FTRACE_MCOUNT_RECORD
779 525
780 config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_EN !! 526 config FTRACE_SELFTEST
781 bool 527 bool
782 depends on FTRACE_MCOUNT_RECORD <<
783 528
784 config FTRACE_MCOUNT_USE_CC !! 529 config FTRACE_STARTUP_TEST
785 def_bool y !! 530 bool "Perform a startup test on ftrace"
786 depends on $(cc-option,-mrecord-mcount !! 531 depends on GENERIC_TRACER
787 depends on !FTRACE_MCOUNT_USE_PATCHABL !! 532 select FTRACE_SELFTEST
788 depends on FTRACE_MCOUNT_RECORD !! 533 help
>> 534 This option performs a series of startup tests on ftrace. On bootup
>> 535 a series of tests are made to verify that the tracer is
>> 536 functioning properly. It will do tests on all the configured
>> 537 tracers of ftrace.
789 538
790 config FTRACE_MCOUNT_USE_OBJTOOL !! 539 config EVENT_TRACE_TEST_SYSCALLS
791 def_bool y !! 540 bool "Run selftest on syscall events"
792 depends on HAVE_OBJTOOL_MCOUNT !! 541 depends on FTRACE_STARTUP_TEST
793 depends on !FTRACE_MCOUNT_USE_PATCHABL !! 542 help
794 depends on !FTRACE_MCOUNT_USE_CC !! 543 This option will also enable testing every syscall event.
795 depends on FTRACE_MCOUNT_RECORD !! 544 It only enables the event and disables it and runs various loads
796 select OBJTOOL !! 545 with the event enabled. This adds a bit more time for kernel boot
>> 546 up since it runs this on every system call defined.
797 547
798 config FTRACE_MCOUNT_USE_RECORDMCOUNT !! 548 TBD - enable a way to actually call the syscalls as we test their
799 def_bool y !! 549 events
800 depends on !FTRACE_MCOUNT_USE_PATCHABL !! 550
801 depends on !FTRACE_MCOUNT_USE_CC !! 551 config MMIOTRACE
802 depends on !FTRACE_MCOUNT_USE_OBJTOOL !! 552 bool "Memory mapped IO tracing"
803 depends on FTRACE_MCOUNT_RECORD !! 553 depends on HAVE_MMIOTRACE_SUPPORT && PCI
>> 554 select GENERIC_TRACER
>> 555 help
>> 556 Mmiotrace traces Memory Mapped I/O access and is meant for
>> 557 debugging and reverse engineering. It is called from the ioremap
>> 558 implementation and works via page faults. Tracing is disabled by
>> 559 default and can be enabled at run-time.
>> 560
>> 561 See Documentation/trace/mmiotrace.txt.
>> 562 If you are not helping to develop drivers, say N.
804 563
805 config TRACING_MAP 564 config TRACING_MAP
806 bool 565 bool
807 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 566 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
808 help 567 help
809 tracing_map is a special-purpose loc 568 tracing_map is a special-purpose lock-free map for tracing,
810 separated out as a stand-alone facil 569 separated out as a stand-alone facility in order to allow it
811 to be shared between multiple tracer 570 to be shared between multiple tracers. It isn't meant to be
812 generally used outside of that conte 571 generally used outside of that context, and is normally
813 selected by tracers that use it. 572 selected by tracers that use it.
814 573
815 config SYNTH_EVENTS <<
816 bool "Synthetic trace events" <<
817 select TRACING <<
818 select DYNAMIC_EVENTS <<
819 default n <<
820 help <<
821 Synthetic events are user-defined tr <<
822 used to combine data from other trac <<
823 data source. Synthetic events can b <<
824 via the trace() action of histogram <<
825 by way of an in-kernel API. <<
826 <<
827 See Documentation/trace/events.rst o <<
828 Documentation/trace/histogram.rst fo <<
829 <<
830 If in doubt, say N. <<
831 <<
832 config USER_EVENTS <<
833 bool "User trace events" <<
834 select TRACING <<
835 select DYNAMIC_EVENTS <<
836 help <<
837 User trace events are user-defined t <<
838 can be used like an existing kernel <<
839 events are generated by writing to a <<
840 processes can determine if their tra <<
841 generated by registering a value and <<
842 that reflects when it is enabled or <<
843 <<
844 See Documentation/trace/user_events. <<
845 If in doubt, say N. <<
846 <<
847 config HIST_TRIGGERS 574 config HIST_TRIGGERS
848 bool "Histogram triggers" 575 bool "Histogram triggers"
849 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 576 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
850 select TRACING_MAP 577 select TRACING_MAP
851 select TRACING 578 select TRACING
852 select DYNAMIC_EVENTS <<
853 select SYNTH_EVENTS <<
854 default n 579 default n
855 help 580 help
856 Hist triggers allow one or more arbi 581 Hist triggers allow one or more arbitrary trace event fields
857 to be aggregated into hash tables an 582 to be aggregated into hash tables and dumped to stdout by
858 reading a debugfs/tracefs file. The 583 reading a debugfs/tracefs file. They're useful for
859 gathering quick and dirty (though pr 584 gathering quick and dirty (though precise) summaries of
860 event activity as an initial guide f 585 event activity as an initial guide for further investigation
861 using more advanced tools. 586 using more advanced tools.
862 587
863 Inter-event tracing of quantities su !! 588 See Documentation/trace/events.txt.
864 supported using hist triggers under <<
865 <<
866 See Documentation/trace/histogram.rs <<
867 If in doubt, say N. 589 If in doubt, say N.
868 590
869 config TRACE_EVENT_INJECT !! 591 config MMIOTRACE_TEST
870 bool "Trace event injection" !! 592 tristate "Test module for mmiotrace"
871 depends on TRACING !! 593 depends on MMIOTRACE && m
872 help 594 help
873 Allow user-space to inject a specifi !! 595 This is a dumb module for testing mmiotrace. It is very dangerous
874 buffer. This is mainly used for test !! 596 as it will write garbage to IO memory starting at a given address.
>> 597 However, it should be safe to use on e.g. unused portion of VRAM.
875 598
876 If unsure, say N. !! 599 Say N, unless you absolutely know what you are doing.
877 600
878 config TRACEPOINT_BENCHMARK 601 config TRACEPOINT_BENCHMARK
879 bool "Add tracepoint that benchmarks t !! 602 bool "Add tracepoint that benchmarks tracepoints"
880 help 603 help
881 This option creates the tracepoint "b 604 This option creates the tracepoint "benchmark:benchmark_event".
882 When the tracepoint is enabled, it ki 605 When the tracepoint is enabled, it kicks off a kernel thread that
883 goes into an infinite loop (calling c !! 606 goes into an infinite loop (calling cond_sched() to let other tasks
884 run), and calls the tracepoint. Each 607 run), and calls the tracepoint. Each iteration will record the time
885 it took to write to the tracepoint an 608 it took to write to the tracepoint and the next iteration that
886 data will be passed to the tracepoint 609 data will be passed to the tracepoint itself. That is, the tracepoint
887 will report the time it took to do th 610 will report the time it took to do the previous tracepoint.
888 The string written to the tracepoint 611 The string written to the tracepoint is a static string of 128 bytes
889 to keep the time the same. The initia 612 to keep the time the same. The initial string is simply a write of
890 "START". The second string records th 613 "START". The second string records the cold cache time of the first
891 write which is not added to the rest 614 write which is not added to the rest of the calculations.
892 615
893 As it is a tight loop, it benchmarks 616 As it is a tight loop, it benchmarks as hot cache. That's fine because
894 we care most about hot paths that are 617 we care most about hot paths that are probably in cache already.
895 618
896 An example of the output: 619 An example of the output:
897 620
898 START 621 START
899 first=3672 [COLD CACHED] 622 first=3672 [COLD CACHED]
900 last=632 first=3672 max=632 min= 623 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
901 last=278 first=3672 max=632 min= 624 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
902 last=277 first=3672 max=632 min= 625 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
903 last=273 first=3672 max=632 min= 626 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
904 last=273 first=3672 max=632 min= 627 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
905 last=281 first=3672 max=632 min= 628 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
906 629
907 630
908 config RING_BUFFER_BENCHMARK 631 config RING_BUFFER_BENCHMARK
909 tristate "Ring buffer benchmark stress 632 tristate "Ring buffer benchmark stress tester"
910 depends on RING_BUFFER 633 depends on RING_BUFFER
911 help 634 help
912 This option creates a test to stress 635 This option creates a test to stress the ring buffer and benchmark it.
913 It creates its own ring buffer such 636 It creates its own ring buffer such that it will not interfere with
914 any other users of the ring buffer ( 637 any other users of the ring buffer (such as ftrace). It then creates
915 a producer and consumer that will ru 638 a producer and consumer that will run for 10 seconds and sleep for
916 10 seconds. Each interval it will pr 639 10 seconds. Each interval it will print out the number of events
917 it recorded and give a rough estimat 640 it recorded and give a rough estimate of how long each iteration took.
918 641
919 It does not disable interrupts or ra 642 It does not disable interrupts or raise its priority, so it may be
920 affected by processes that are runni 643 affected by processes that are running.
921 644
922 If unsure, say N. 645 If unsure, say N.
923 646
>> 647 config RING_BUFFER_STARTUP_TEST
>> 648 bool "Ring buffer startup self test"
>> 649 depends on RING_BUFFER
>> 650 help
>> 651 Run a simple self test on the ring buffer on boot up. Late in the
>> 652 kernel boot sequence, the test will start that kicks off
>> 653 a thread per cpu. Each thread will write various size events
>> 654 into the ring buffer. Another thread is created to send IPIs
>> 655 to each of the threads, where the IPI handler will also write
>> 656 to the ring buffer, to test/stress the nesting ability.
>> 657 If any anomalies are discovered, a warning will be displayed
>> 658 and all ring buffers will be disabled.
>> 659
>> 660 The test runs for 10 seconds. This will slow your boot time
>> 661 by at least 10 more seconds.
>> 662
>> 663 At the end of the test, statics and more checks are done.
>> 664 It will output the stats of each per cpu buffer. What
>> 665 was written, the sizes, what was read, what was lost, and
>> 666 other similar details.
>> 667
>> 668 If unsure, say N
>> 669
924 config TRACE_EVAL_MAP_FILE 670 config TRACE_EVAL_MAP_FILE
925 bool "Show eval mappings for trace even 671 bool "Show eval mappings for trace events"
926 depends on TRACING 672 depends on TRACING
927 help 673 help
928 The "print fmt" of the trace events wi 674 The "print fmt" of the trace events will show the enum/sizeof names
929 instead of their values. This can caus !! 675 instead of their values. This can cause problems for user space tools
930 that use this string to parse the raw 676 that use this string to parse the raw data as user space does not know
931 how to convert the string to its value 677 how to convert the string to its value.
932 678
933 To fix this, there's a special macro i 679 To fix this, there's a special macro in the kernel that can be used
934 to convert an enum/sizeof into its val 680 to convert an enum/sizeof into its value. If this macro is used, then
935 the print fmt strings will be converte 681 the print fmt strings will be converted to their values.
936 682
937 If something does not get converted pr 683 If something does not get converted properly, this option can be
938 used to show what enums/sizeof the ker 684 used to show what enums/sizeof the kernel tried to convert.
939 685
940 This option is for debugging the conve 686 This option is for debugging the conversions. A file is created
941 in the tracing directory called "eval_ 687 in the tracing directory called "eval_map" that will show the
942 names matched with their values and wh 688 names matched with their values and what trace event system they
943 belong too. 689 belong too.
944 690
945 Normally, the mapping of the strings t 691 Normally, the mapping of the strings to values will be freed after
946 boot up or module load. With this opti 692 boot up or module load. With this option, they will not be freed, as
947 they are needed for the "eval_map" fil 693 they are needed for the "eval_map" file. Enabling this option will
948 increase the memory footprint of the r 694 increase the memory footprint of the running kernel.
949 695
950 If unsure, say N. !! 696 If unsure, say N
951 697
952 config FTRACE_RECORD_RECURSION !! 698 config TRACING_EVENTS_GPIO
953 bool "Record functions that recurse in !! 699 bool "Trace gpio events"
954 depends on FUNCTION_TRACER !! 700 depends on GPIOLIB
955 help <<
956 All callbacks that attach to the fun <<
957 of protection against recursion. Eve <<
958 it adds overhead. This option will c <<
959 file system called "recursed_functio <<
960 that triggered a recursion. <<
961 <<
962 This will add more overhead to cases <<
963 <<
964 If unsure, say N <<
965 <<
966 config FTRACE_RECORD_RECURSION_SIZE <<
967 int "Max number of recursed functions <<
968 default 128 <<
969 depends on FTRACE_RECORD_RECURSION <<
970 help <<
971 This defines the limit of number of <<
972 listed in the "recursed_functions" f <<
973 the functions that caused a recursio <<
974 This file can be reset, but the limi <<
975 size at runtime. <<
976 <<
977 config FTRACE_VALIDATE_RCU_IS_WATCHING <<
978 bool "Validate RCU is on during ftrace <<
979 depends on FUNCTION_TRACER <<
980 depends on ARCH_WANTS_NO_INSTR <<
981 help <<
982 All callbacks that attach to the fun <<
983 protection against recursion. This o <<
984 ftrace (and other users of ftrace_te <<
985 called outside of RCU, as if they ar <<
986 also has a noticeable overhead when <<
987 <<
988 If unsure, say N <<
989 <<
990 config RING_BUFFER_RECORD_RECURSION <<
991 bool "Record functions that recurse in <<
992 depends on FTRACE_RECORD_RECURSION <<
993 # default y, because it is coupled wit <<
994 default y 701 default y
995 help 702 help
996 The ring buffer has its own internal !! 703 Enable tracing events for gpio subsystem
997 recursion happens it won't cause har <<
998 but it does cause unwanted overhead. <<
999 place where recursion was detected i <<
1000 file. <<
1001 <<
1002 This will add more overhead to case <<
1003 <<
1004 config GCOV_PROFILE_FTRACE <<
1005 bool "Enable GCOV profiling on ftrace <<
1006 depends on GCOV_KERNEL <<
1007 help <<
1008 Enable GCOV profiling on ftrace sub <<
1009 which functions/lines are tested. <<
1010 <<
1011 If unsure, say N. <<
1012 704
1013 Note that on a kernel compiled with !! 705 endif # FTRACE
1014 run significantly slower. <<
1015 <<
1016 config FTRACE_SELFTEST <<
1017 bool <<
1018 <<
1019 config FTRACE_STARTUP_TEST <<
1020 bool "Perform a startup test on ftrac <<
1021 depends on GENERIC_TRACER <<
1022 select FTRACE_SELFTEST <<
1023 help <<
1024 This option performs a series of st <<
1025 a series of tests are made to verif <<
1026 functioning properly. It will do te <<
1027 tracers of ftrace. <<
1028 <<
1029 config EVENT_TRACE_STARTUP_TEST <<
1030 bool "Run selftest on trace events" <<
1031 depends on FTRACE_STARTUP_TEST <<
1032 default y <<
1033 help <<
1034 This option performs a test on all <<
1035 It basically just enables each even <<
1036 will trigger events (not necessaril <<
1037 This may take some time run as ther <<
1038 <<
1039 config EVENT_TRACE_TEST_SYSCALLS <<
1040 bool "Run selftest on syscall events" <<
1041 depends on EVENT_TRACE_STARTUP_TEST <<
1042 help <<
1043 This option will also enable testing <<
1044 It only enables the event and disabl <<
1045 with the event enabled. This adds a <<
1046 up since it runs this on every syste <<
1047 <<
1048 TBD - enable a way to actually call <<
1049 events <<
1050 <<
1051 config FTRACE_SORT_STARTUP_TEST <<
1052 bool "Verify compile time sorting of f <<
1053 depends on DYNAMIC_FTRACE <<
1054 depends on BUILDTIME_MCOUNT_SORT <<
1055 help <<
1056 Sorting of the mcount_loc sections t <<
1057 where the ftrace knows where to patc <<
1058 and other callbacks is done at compi <<
1059 is not done correctly, it will cause <<
1060 When this is set, the sorted section <<
1061 are in deed sorted and will warn if <<
1062 <<
1063 If unsure, say N <<
1064 <<
1065 config RING_BUFFER_STARTUP_TEST <<
1066 bool "Ring buffer startup self test" <<
1067 depends on RING_BUFFER <<
1068 help <<
1069 Run a simple self test on the ring b <<
1070 kernel boot sequence, the test will <<
1071 a thread per cpu. Each thread will w <<
1072 into the ring buffer. Another thread <<
1073 to each of the threads, where the IP <<
1074 to the ring buffer, to test/stress t <<
1075 If any anomalies are discovered, a w <<
1076 and all ring buffers will be disable <<
1077 <<
1078 The test runs for 10 seconds. This w <<
1079 by at least 10 more seconds. <<
1080 <<
1081 At the end of the test, statistics a <<
1082 It will output the stats of each per <<
1083 was written, the sizes, what was rea <<
1084 other similar details. <<
1085 <<
1086 If unsure, say N <<
1087 <<
1088 config RING_BUFFER_VALIDATE_TIME_DELTAS <<
1089 bool "Verify ring buffer time stamp d <<
1090 depends on RING_BUFFER <<
1091 help <<
1092 This will audit the time stamps on <<
1093 buffer to make sure that all the ti <<
1094 events on a sub buffer matches the <<
1095 This audit is performed for every e <<
1096 interrupted, or interrupting anothe <<
1097 is also made when traversing sub bu <<
1098 that all the deltas on the previous <<
1099 add up to be greater than the curre <<
1100 <<
1101 NOTE: This adds significant overhea <<
1102 and should only be used to test the <<
1103 Do not use it on production systems <<
1104 <<
1105 Only say Y if you understand what t <<
1106 still want it enabled. Otherwise sa <<
1107 <<
1108 config MMIOTRACE_TEST <<
1109 tristate "Test module for mmiotrace" <<
1110 depends on MMIOTRACE && m <<
1111 help <<
1112 This is a dumb module for testing m <<
1113 as it will write garbage to IO memo <<
1114 However, it should be safe to use o <<
1115 <<
1116 Say N, unless you absolutely know w <<
1117 <<
1118 config PREEMPTIRQ_DELAY_TEST <<
1119 tristate "Test module to create a pre <<
1120 depends on m <<
1121 help <<
1122 Select this option to build a test <<
1123 tracers by executing a preempt or i <<
1124 configurable delay. The module busy <<
1125 critical section. <<
1126 <<
1127 For example, the following invocati <<
1128 irq-disabled critical sections for <<
1129 modprobe preemptirq_delay_test test <<
1130 <<
1131 What's more, if you want to attach <<
1132 tracer is running on, specify cpu_a <<
1133 command. <<
1134 <<
1135 If unsure, say N <<
1136 <<
1137 config SYNTH_EVENT_GEN_TEST <<
1138 tristate "Test module for in-kernel s <<
1139 depends on SYNTH_EVENTS && m <<
1140 help <<
1141 This option creates a test module t <<
1142 functionality of in-kernel syntheti <<
1143 generation. <<
1144 <<
1145 To test, insert the module, and the <<
1146 for the generated sample events. <<
1147 <<
1148 If unsure, say N. <<
1149 <<
1150 config KPROBE_EVENT_GEN_TEST <<
1151 tristate "Test module for in-kernel k <<
1152 depends on KPROBE_EVENTS && m <<
1153 help <<
1154 This option creates a test module t <<
1155 functionality of in-kernel kprobe e <<
1156 <<
1157 To test, insert the module, and the <<
1158 for the generated kprobe events. <<
1159 <<
1160 If unsure, say N. <<
1161 <<
1162 config HIST_TRIGGERS_DEBUG <<
1163 bool "Hist trigger debug support" <<
1164 depends on HIST_TRIGGERS <<
1165 help <<
1166 Add "hist_debug" file for each even <<
1167 dump out a bunch of internal detail <<
1168 defined on that event. <<
1169 <<
1170 The hist_debug file serves a couple <<
1171 <<
1172 - Helps developers verify that no <<
1173 <<
1174 - Provides educational informatio <<
1175 of the hist trigger internals a <<
1176 Documentation/trace/histogram-d <<
1177 <<
1178 The hist_debug output only covers t <<
1179 related to the histogram definition <<
1180 display the internals of map bucket <<
1181 running histograms. <<
1182 <<
1183 If unsure, say N. <<
1184 706
1185 source "kernel/trace/rv/Kconfig" !! 707 endif # TRACING_SUPPORT
1186 708
1187 endif # FTRACE <<
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