2 # Architectures that offer an FTRACE implementation should select HAVE_FTRACE:
12 config HAVE_DYNAMIC_FTRACE
15 config HAVE_FTRACE_MCOUNT_RECORD
18 config TRACER_MAX_TRACE
28 bool "Kernel Function Tracer"
29 depends on HAVE_FTRACE
30 depends on DEBUG_KERNEL
33 select CONTEXT_SWITCH_TRACER
35 Enable the kernel to trace every kernel function. This is done
36 by using a compiler feature to insert a small, 5-byte No-Operation
37 instruction to the beginning of every kernel function, which NOP
38 sequence is then dynamically patched into a tracer call when
39 tracing is enabled by the administrator. If it's runtime disabled
40 (the bootup default), then the overhead of the instructions is very
41 small and not measurable even in micro-benchmarks.
44 bool "Interrupts-off Latency Tracer"
46 depends on TRACE_IRQFLAGS_SUPPORT
47 depends on GENERIC_TIME
48 depends on HAVE_FTRACE
49 depends on DEBUG_KERNEL
52 select TRACER_MAX_TRACE
54 This option measures the time spent in irqs-off critical
55 sections, with microsecond accuracy.
57 The default measurement method is a maximum search, which is
58 disabled by default and can be runtime (re-)started
61 echo 0 > /debugfs/tracing/tracing_max_latency
63 (Note that kernel size and overhead increases with this option
64 enabled. This option and the preempt-off timing option can be
65 used together or separately.)
68 bool "Preemption-off Latency Tracer"
70 depends on GENERIC_TIME
72 depends on HAVE_FTRACE
73 depends on DEBUG_KERNEL
75 select TRACER_MAX_TRACE
77 This option measures the time spent in preemption off critical
78 sections, with microsecond accuracy.
80 The default measurement method is a maximum search, which is
81 disabled by default and can be runtime (re-)started
84 echo 0 > /debugfs/tracing/tracing_max_latency
86 (Note that kernel size and overhead increases with this option
87 enabled. This option and the irqs-off timing option can be
88 used together or separately.)
95 This tracer provides the trace needed by the 'Sysprof' userspace
99 bool "Scheduling Latency Tracer"
100 depends on HAVE_FTRACE
101 depends on DEBUG_KERNEL
103 select CONTEXT_SWITCH_TRACER
104 select TRACER_MAX_TRACE
106 This tracer tracks the latency of the highest priority task
107 to be scheduled in, starting from the point it has woken up.
109 config CONTEXT_SWITCH_TRACER
110 bool "Trace process context switches"
111 depends on HAVE_FTRACE
112 depends on DEBUG_KERNEL
116 This tracer gets called from the context switch and records
117 all switching of tasks.
120 bool "Trace boot initcalls"
121 depends on HAVE_FTRACE
122 depends on DEBUG_KERNEL
125 This tracer helps developers to optimize boot times: it records
126 the timings of the initcalls. Its aim is to be parsed by the
127 /scripts/bootgraph.pl tool to produce pretty graphics about
128 boot inefficiencies, giving a visual representation of the
129 delays during initcalls. Note that tracers self tests can't
130 be enabled if this tracer is selected since only one tracer
131 should touch the tracing buffer at a time.
134 bool "Trace max stack"
135 depends on HAVE_FTRACE
136 depends on DEBUG_KERNEL
140 This tracer records the max stack of the kernel, and displays
141 it in debugfs/tracing/stack_trace
143 config DYNAMIC_FTRACE
144 bool "enable/disable ftrace tracepoints dynamically"
146 depends on HAVE_DYNAMIC_FTRACE
147 depends on DEBUG_KERNEL
150 This option will modify all the calls to ftrace dynamically
151 (will patch them out of the binary image and replaces them
152 with a No-Op instruction) as they are called. A table is
153 created to dynamically enable them again.
155 This way a CONFIG_FTRACE kernel is slightly larger, but otherwise
156 has native performance as long as no tracing is active.
158 The changes to the code are done by a kernel thread that
159 wakes up once a second and checks to see if any ftrace calls
160 were made. If so, it runs stop_machine (stops all CPUS)
161 and modifies the code to jump over the call to ftrace.
163 config FTRACE_MCOUNT_RECORD
165 depends on DYNAMIC_FTRACE
166 depends on HAVE_FTRACE_MCOUNT_RECORD
168 config FTRACE_SELFTEST
171 config FTRACE_STARTUP_TEST
172 bool "Perform a startup test on ftrace"
173 depends on TRACING && DEBUG_KERNEL && !BOOT_TRACER
174 select FTRACE_SELFTEST
176 This option performs a series of startup tests on ftrace. On bootup
177 a series of tests are made to verify that the tracer is
178 functioning properly. It will do tests on all the configured