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- # SPDX-License-Identifier: GPL-2.0-only
- #
- # Architectures that offer an FUNCTION_TRACER implementation should
- # select HAVE_FUNCTION_TRACER:
- #
- config USER_STACKTRACE_SUPPORT
- bool
- config NOP_TRACER
- bool
- config HAVE_RETHOOK
- bool
- config RETHOOK
- bool
- depends on HAVE_RETHOOK
- help
- Enable generic return hooking feature. This is an internal
- API, which will be used by other function-entry hooking
- features like fprobe and kprobes.
- config HAVE_FUNCTION_TRACER
- bool
- help
- See Documentation/trace/ftrace-design.rst
- config HAVE_FUNCTION_GRAPH_TRACER
- bool
- help
- See Documentation/trace/ftrace-design.rst
- config HAVE_DYNAMIC_FTRACE
- bool
- help
- See Documentation/trace/ftrace-design.rst
- config HAVE_DYNAMIC_FTRACE_WITH_REGS
- bool
- config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
- bool
- config HAVE_DYNAMIC_FTRACE_WITH_ARGS
- bool
- help
- If this is set, then arguments and stack can be found from
- the pt_regs passed into the function callback regs parameter
- by default, even without setting the REGS flag in the ftrace_ops.
- This allows for use of regs_get_kernel_argument() and
- kernel_stack_pointer().
- config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE
- bool
- help
- If the architecture generates __patchable_function_entries sections
- but does not want them included in the ftrace locations.
- config HAVE_FTRACE_MCOUNT_RECORD
- bool
- help
- See Documentation/trace/ftrace-design.rst
- config HAVE_SYSCALL_TRACEPOINTS
- bool
- help
- See Documentation/trace/ftrace-design.rst
- config HAVE_FENTRY
- bool
- help
- Arch supports the gcc options -pg with -mfentry
- config HAVE_NOP_MCOUNT
- bool
- help
- Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
- config HAVE_OBJTOOL_MCOUNT
- bool
- help
- Arch supports objtool --mcount
- config HAVE_C_RECORDMCOUNT
- bool
- help
- C version of recordmcount available?
- config HAVE_BUILDTIME_MCOUNT_SORT
- bool
- help
- An architecture selects this if it sorts the mcount_loc section
- at build time.
- config BUILDTIME_MCOUNT_SORT
- bool
- default y
- depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
- help
- Sort the mcount_loc section at build time.
- config TRACER_MAX_TRACE
- bool
- config TRACE_CLOCK
- bool
- config RING_BUFFER
- bool
- select TRACE_CLOCK
- select IRQ_WORK
- config EVENT_TRACING
- select CONTEXT_SWITCH_TRACER
- select GLOB
- bool
- config CONTEXT_SWITCH_TRACER
- bool
- config RING_BUFFER_ALLOW_SWAP
- bool
- help
- Allow the use of ring_buffer_swap_cpu.
- Adds a very slight overhead to tracing when enabled.
- config PREEMPTIRQ_TRACEPOINTS
- bool
- depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
- select TRACING
- default y
- help
- Create preempt/irq toggle tracepoints if needed, so that other parts
- of the kernel can use them to generate or add hooks to them.
- config IPC_LOGGING
- tristate "Debug Logging for IPC Drivers"
- depends on DEBUG_FS
- help
- IPC Logging driver provides a logging option for IPC Drivers.
- This provides a cyclic buffer based logging support in a driver
- specific context. This driver also provides a debugfs interface
- to dump the logs in a live fashion.
- If in doubt, say no.
- config IPC_LOGGING_CDEV
- tristate "Ipc Logging Character Device"
- depends on IPC_LOGGING
- help
- Character device for ipc logging. Reading it will extract ipc logs up to
- the specified size and increment the read index of the ipc log buffer.
- Read function will return EOF when there is no longer any data to read
- in the ipc log buffer.
- config IPC_LOG_MINIDUMP_BUFFERS
- int "Ipc log buffers count that can be dumped with minidump"
- depends on IPC_LOGGING
- default 0
- help
- This option is used to configure maximum number of ipc log
- buffers that can be dumped by minidump.
- # All tracer options should select GENERIC_TRACER. For those options that are
- # enabled by all tracers (context switch and event tracer) they select TRACING.
- # This allows those options to appear when no other tracer is selected. But the
- # options do not appear when something else selects it. We need the two options
- # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
- # hiding of the automatic options.
- config TRACING
- bool
- select RING_BUFFER
- select STACKTRACE if STACKTRACE_SUPPORT
- select TRACEPOINTS
- select NOP_TRACER
- select BINARY_PRINTF
- select EVENT_TRACING
- select TRACE_CLOCK
- select TASKS_RCU if PREEMPTION
- config GENERIC_TRACER
- bool
- select TRACING
- #
- # Minimum requirements an architecture has to meet for us to
- # be able to offer generic tracing facilities:
- #
- config TRACING_SUPPORT
- bool
- depends on TRACE_IRQFLAGS_SUPPORT
- depends on STACKTRACE_SUPPORT
- default y
- menuconfig FTRACE
- bool "Tracers"
- depends on TRACING_SUPPORT
- default y if DEBUG_KERNEL
- help
- Enable the kernel tracing infrastructure.
- if FTRACE
- config BOOTTIME_TRACING
- bool "Boot-time Tracing support"
- depends on TRACING
- select BOOT_CONFIG
- help
- Enable developer to setup ftrace subsystem via supplemental
- kernel cmdline at boot time for debugging (tracing) driver
- initialization and boot process.
- config FUNCTION_TRACER
- bool "Kernel Function Tracer"
- depends on HAVE_FUNCTION_TRACER
- select KALLSYMS
- select GENERIC_TRACER
- select CONTEXT_SWITCH_TRACER
- select GLOB
- select TASKS_RCU if PREEMPTION
- select TASKS_RUDE_RCU
- help
- Enable the kernel to trace every kernel function. This is done
- by using a compiler feature to insert a small, 5-byte No-Operation
- instruction at the beginning of every kernel function, which NOP
- sequence is then dynamically patched into a tracer call when
- tracing is enabled by the administrator. If it's runtime disabled
- (the bootup default), then the overhead of the instructions is very
- small and not measurable even in micro-benchmarks (at least on
- x86, but may have impact on other architectures).
- config FUNCTION_GRAPH_TRACER
- bool "Kernel Function Graph Tracer"
- depends on HAVE_FUNCTION_GRAPH_TRACER
- depends on FUNCTION_TRACER
- depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
- default y
- help
- Enable the kernel to trace a function at both its return
- and its entry.
- Its first purpose is to trace the duration of functions and
- draw a call graph for each thread with some information like
- the return value. This is done by setting the current return
- address on the current task structure into a stack of calls.
- config DYNAMIC_FTRACE
- bool "enable/disable function tracing dynamically"
- depends on FUNCTION_TRACER
- depends on HAVE_DYNAMIC_FTRACE
- default y
- help
- This option will modify all the calls to function tracing
- dynamically (will patch them out of the binary image and
- replace them with a No-Op instruction) on boot up. During
- compile time, a table is made of all the locations that ftrace
- can function trace, and this table is linked into the kernel
- image. When this is enabled, functions can be individually
- enabled, and the functions not enabled will not affect
- performance of the system.
- See the files in /sys/kernel/debug/tracing:
- available_filter_functions
- set_ftrace_filter
- set_ftrace_notrace
- This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
- otherwise has native performance as long as no tracing is active.
- config DYNAMIC_FTRACE_WITH_REGS
- def_bool y
- depends on DYNAMIC_FTRACE
- depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
- config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
- def_bool y
- depends on DYNAMIC_FTRACE_WITH_REGS
- depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
- config DYNAMIC_FTRACE_WITH_ARGS
- def_bool y
- depends on DYNAMIC_FTRACE
- depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
- config FPROBE
- bool "Kernel Function Probe (fprobe)"
- depends on FUNCTION_TRACER
- depends on DYNAMIC_FTRACE_WITH_REGS
- depends on HAVE_RETHOOK
- select RETHOOK
- default n
- help
- This option enables kernel function probe (fprobe) based on ftrace.
- The fprobe is similar to kprobes, but probes only for kernel function
- entries and exits. This also can probe multiple functions by one
- fprobe.
- If unsure, say N.
- config FUNCTION_PROFILER
- bool "Kernel function profiler"
- depends on FUNCTION_TRACER
- default n
- help
- This option enables the kernel function profiler. A file is created
- in debugfs called function_profile_enabled which defaults to zero.
- When a 1 is echoed into this file profiling begins, and when a
- zero is entered, profiling stops. A "functions" file is created in
- the trace_stat directory; this file shows the list of functions that
- have been hit and their counters.
- If in doubt, say N.
- config STACK_TRACER
- bool "Trace max stack"
- depends on HAVE_FUNCTION_TRACER
- select FUNCTION_TRACER
- select STACKTRACE
- select KALLSYMS
- help
- This special tracer records the maximum stack footprint of the
- kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
- This tracer works by hooking into every function call that the
- kernel executes, and keeping a maximum stack depth value and
- stack-trace saved. If this is configured with DYNAMIC_FTRACE
- then it will not have any overhead while the stack tracer
- is disabled.
- To enable the stack tracer on bootup, pass in 'stacktrace'
- on the kernel command line.
- The stack tracer can also be enabled or disabled via the
- sysctl kernel.stack_tracer_enabled
- Say N if unsure.
- config TRACE_PREEMPT_TOGGLE
- bool
- help
- Enables hooks which will be called when preemption is first disabled,
- and last enabled.
- config IRQSOFF_TRACER
- bool "Interrupts-off Latency Tracer"
- default n
- depends on TRACE_IRQFLAGS_SUPPORT
- select TRACE_IRQFLAGS
- select GENERIC_TRACER
- select TRACER_MAX_TRACE
- select RING_BUFFER_ALLOW_SWAP
- select TRACER_SNAPSHOT
- select TRACER_SNAPSHOT_PER_CPU_SWAP
- help
- This option measures the time spent in irqs-off critical
- sections, with microsecond accuracy.
- The default measurement method is a maximum search, which is
- disabled by default and can be runtime (re-)started
- via:
- echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
- (Note that kernel size and overhead increase with this option
- enabled. This option and the preempt-off timing option can be
- used together or separately.)
- config PREEMPT_TRACER
- bool "Preemption-off Latency Tracer"
- default n
- depends on PREEMPTION
- select GENERIC_TRACER
- select TRACER_MAX_TRACE
- select RING_BUFFER_ALLOW_SWAP
- select TRACER_SNAPSHOT
- select TRACER_SNAPSHOT_PER_CPU_SWAP
- select TRACE_PREEMPT_TOGGLE
- help
- This option measures the time spent in preemption-off critical
- sections, with microsecond accuracy.
- The default measurement method is a maximum search, which is
- disabled by default and can be runtime (re-)started
- via:
- echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
- (Note that kernel size and overhead increase with this option
- enabled. This option and the irqs-off timing option can be
- used together or separately.)
- config SCHED_TRACER
- bool "Scheduling Latency Tracer"
- select GENERIC_TRACER
- select CONTEXT_SWITCH_TRACER
- select TRACER_MAX_TRACE
- select TRACER_SNAPSHOT
- help
- This tracer tracks the latency of the highest priority task
- to be scheduled in, starting from the point it has woken up.
- config HWLAT_TRACER
- bool "Tracer to detect hardware latencies (like SMIs)"
- select GENERIC_TRACER
- select TRACER_MAX_TRACE
- help
- This tracer, when enabled will create one or more kernel threads,
- depending on what the cpumask file is set to, which each thread
- spinning in a loop looking for interruptions caused by
- something other than the kernel. For example, if a
- System Management Interrupt (SMI) takes a noticeable amount of
- time, this tracer will detect it. This is useful for testing
- if a system is reliable for Real Time tasks.
- Some files are created in the tracing directory when this
- is enabled:
- hwlat_detector/width - time in usecs for how long to spin for
- hwlat_detector/window - time in usecs between the start of each
- iteration
- A kernel thread is created that will spin with interrupts disabled
- for "width" microseconds in every "window" cycle. It will not spin
- for "window - width" microseconds, where the system can
- continue to operate.
- The output will appear in the trace and trace_pipe files.
- When the tracer is not running, it has no affect on the system,
- but when it is running, it can cause the system to be
- periodically non responsive. Do not run this tracer on a
- production system.
- To enable this tracer, echo in "hwlat" into the current_tracer
- file. Every time a latency is greater than tracing_thresh, it will
- be recorded into the ring buffer.
- config OSNOISE_TRACER
- bool "OS Noise tracer"
- select GENERIC_TRACER
- select TRACER_MAX_TRACE
- help
- In the context of high-performance computing (HPC), the Operating
- System Noise (osnoise) refers to the interference experienced by an
- application due to activities inside the operating system. In the
- context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
- can cause noise to the system. Moreover, hardware-related jobs can
- also cause noise, for example, via SMIs.
- The osnoise tracer leverages the hwlat_detector by running a similar
- loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
- the sources of osnoise during its execution. The osnoise tracer takes
- note of the entry and exit point of any source of interferences,
- increasing a per-cpu interference counter. It saves an interference
- counter for each source of interference. The interference counter for
- NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
- observes these interferences' entry events. When a noise happens
- without any interference from the operating system level, the
- hardware noise counter increases, pointing to a hardware-related
- noise. In this way, osnoise can account for any source of
- interference. At the end of the period, the osnoise tracer prints
- the sum of all noise, the max single noise, the percentage of CPU
- available for the thread, and the counters for the noise sources.
- In addition to the tracer, a set of tracepoints were added to
- facilitate the identification of the osnoise source.
- The output will appear in the trace and trace_pipe files.
- To enable this tracer, echo in "osnoise" into the current_tracer
- file.
- config TIMERLAT_TRACER
- bool "Timerlat tracer"
- select OSNOISE_TRACER
- select GENERIC_TRACER
- help
- The timerlat tracer aims to help the preemptive kernel developers
- to find sources of wakeup latencies of real-time threads.
- The tracer creates a per-cpu kernel thread with real-time priority.
- The tracer thread sets a periodic timer to wakeup itself, and goes
- to sleep waiting for the timer to fire. At the wakeup, the thread
- then computes a wakeup latency value as the difference between
- the current time and the absolute time that the timer was set
- to expire.
- The tracer prints two lines at every activation. The first is the
- timer latency observed at the hardirq context before the
- activation of the thread. The second is the timer latency observed
- by the thread, which is the same level that cyclictest reports. The
- ACTIVATION ID field serves to relate the irq execution to its
- respective thread execution.
- The tracer is build on top of osnoise tracer, and the osnoise:
- events can be used to trace the source of interference from NMI,
- IRQs and other threads. It also enables the capture of the
- stacktrace at the IRQ context, which helps to identify the code
- path that can cause thread delay.
- config MMIOTRACE
- bool "Memory mapped IO tracing"
- depends on HAVE_MMIOTRACE_SUPPORT && PCI
- select GENERIC_TRACER
- help
- Mmiotrace traces Memory Mapped I/O access and is meant for
- debugging and reverse engineering. It is called from the ioremap
- implementation and works via page faults. Tracing is disabled by
- default and can be enabled at run-time.
- See Documentation/trace/mmiotrace.rst.
- If you are not helping to develop drivers, say N.
- config ENABLE_DEFAULT_TRACERS
- bool "Trace process context switches and events"
- depends on !GENERIC_TRACER
- select TRACING
- help
- This tracer hooks to various trace points in the kernel,
- allowing the user to pick and choose which trace point they
- want to trace. It also includes the sched_switch tracer plugin.
- config FTRACE_SYSCALLS
- bool "Trace syscalls"
- depends on HAVE_SYSCALL_TRACEPOINTS
- select GENERIC_TRACER
- select KALLSYMS
- help
- Basic tracer to catch the syscall entry and exit events.
- config TRACER_SNAPSHOT
- bool "Create a snapshot trace buffer"
- select TRACER_MAX_TRACE
- help
- Allow tracing users to take snapshot of the current buffer using the
- ftrace interface, e.g.:
- echo 1 > /sys/kernel/debug/tracing/snapshot
- cat snapshot
- config TRACER_SNAPSHOT_PER_CPU_SWAP
- bool "Allow snapshot to swap per CPU"
- depends on TRACER_SNAPSHOT
- select RING_BUFFER_ALLOW_SWAP
- help
- Allow doing a snapshot of a single CPU buffer instead of a
- full swap (all buffers). If this is set, then the following is
- allowed:
- echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
- After which, only the tracing buffer for CPU 2 was swapped with
- the main tracing buffer, and the other CPU buffers remain the same.
- When this is enabled, this adds a little more overhead to the
- trace recording, as it needs to add some checks to synchronize
- recording with swaps. But this does not affect the performance
- of the overall system. This is enabled by default when the preempt
- or irq latency tracers are enabled, as those need to swap as well
- and already adds the overhead (plus a lot more).
- config TRACE_BRANCH_PROFILING
- bool
- select GENERIC_TRACER
- choice
- prompt "Branch Profiling"
- default BRANCH_PROFILE_NONE
- help
- The branch profiling is a software profiler. It will add hooks
- into the C conditionals to test which path a branch takes.
- The likely/unlikely profiler only looks at the conditions that
- are annotated with a likely or unlikely macro.
- The "all branch" profiler will profile every if-statement in the
- kernel. This profiler will also enable the likely/unlikely
- profiler.
- Either of the above profilers adds a bit of overhead to the system.
- If unsure, choose "No branch profiling".
- config BRANCH_PROFILE_NONE
- bool "No branch profiling"
- help
- No branch profiling. Branch profiling adds a bit of overhead.
- Only enable it if you want to analyse the branching behavior.
- Otherwise keep it disabled.
- config PROFILE_ANNOTATED_BRANCHES
- bool "Trace likely/unlikely profiler"
- select TRACE_BRANCH_PROFILING
- help
- This tracer profiles all likely and unlikely macros
- in the kernel. It will display the results in:
- /sys/kernel/debug/tracing/trace_stat/branch_annotated
- Note: this will add a significant overhead; only turn this
- on if you need to profile the system's use of these macros.
- config PROFILE_ALL_BRANCHES
- bool "Profile all if conditionals" if !FORTIFY_SOURCE
- select TRACE_BRANCH_PROFILING
- help
- This tracer profiles all branch conditions. Every if ()
- taken in the kernel is recorded whether it hit or miss.
- The results will be displayed in:
- /sys/kernel/debug/tracing/trace_stat/branch_all
- This option also enables the likely/unlikely profiler.
- This configuration, when enabled, will impose a great overhead
- on the system. This should only be enabled when the system
- is to be analyzed in much detail.
- endchoice
- config TRACING_BRANCHES
- bool
- help
- Selected by tracers that will trace the likely and unlikely
- conditions. This prevents the tracers themselves from being
- profiled. Profiling the tracing infrastructure can only happen
- when the likelys and unlikelys are not being traced.
- config BRANCH_TRACER
- bool "Trace likely/unlikely instances"
- depends on TRACE_BRANCH_PROFILING
- select TRACING_BRANCHES
- help
- This traces the events of likely and unlikely condition
- calls in the kernel. The difference between this and the
- "Trace likely/unlikely profiler" is that this is not a
- histogram of the callers, but actually places the calling
- events into a running trace buffer to see when and where the
- events happened, as well as their results.
- Say N if unsure.
- config BLK_DEV_IO_TRACE
- bool "Support for tracing block IO actions"
- depends on SYSFS
- depends on BLOCK
- select RELAY
- select DEBUG_FS
- select TRACEPOINTS
- select GENERIC_TRACER
- select STACKTRACE
- help
- Say Y here if you want to be able to trace the block layer actions
- on a given queue. Tracing allows you to see any traffic happening
- on a block device queue. For more information (and the userspace
- support tools needed), fetch the blktrace tools from:
- git://git.kernel.dk/blktrace.git
- Tracing also is possible using the ftrace interface, e.g.:
- echo 1 > /sys/block/sda/sda1/trace/enable
- echo blk > /sys/kernel/debug/tracing/current_tracer
- cat /sys/kernel/debug/tracing/trace_pipe
- If unsure, say N.
- config KPROBE_EVENTS
- depends on KPROBES
- depends on HAVE_REGS_AND_STACK_ACCESS_API
- bool "Enable kprobes-based dynamic events"
- select TRACING
- select PROBE_EVENTS
- select DYNAMIC_EVENTS
- default y
- help
- This allows the user to add tracing events (similar to tracepoints)
- on the fly via the ftrace interface. See
- Documentation/trace/kprobetrace.rst for more details.
- Those events can be inserted wherever kprobes can probe, and record
- various register and memory values.
- This option is also required by perf-probe subcommand of perf tools.
- If you want to use perf tools, this option is strongly recommended.
- config KPROBE_EVENTS_ON_NOTRACE
- bool "Do NOT protect notrace function from kprobe events"
- depends on KPROBE_EVENTS
- depends on DYNAMIC_FTRACE
- default n
- help
- This is only for the developers who want to debug ftrace itself
- using kprobe events.
- If kprobes can use ftrace instead of breakpoint, ftrace related
- functions are protected from kprobe-events to prevent an infinite
- recursion or any unexpected execution path which leads to a kernel
- crash.
- This option disables such protection and allows you to put kprobe
- events on ftrace functions for debugging ftrace by itself.
- Note that this might let you shoot yourself in the foot.
- If unsure, say N.
- config UPROBE_EVENTS
- bool "Enable uprobes-based dynamic events"
- depends on ARCH_SUPPORTS_UPROBES
- depends on MMU
- depends on PERF_EVENTS
- select UPROBES
- select PROBE_EVENTS
- select DYNAMIC_EVENTS
- select TRACING
- default y
- help
- This allows the user to add tracing events on top of userspace
- dynamic events (similar to tracepoints) on the fly via the trace
- events interface. Those events can be inserted wherever uprobes
- can probe, and record various registers.
- This option is required if you plan to use perf-probe subcommand
- of perf tools on user space applications.
- config BPF_EVENTS
- depends on BPF_SYSCALL
- depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
- bool
- default y
- help
- This allows the user to attach BPF programs to kprobe, uprobe, and
- tracepoint events.
- config DYNAMIC_EVENTS
- def_bool n
- config PROBE_EVENTS
- def_bool n
- config BPF_KPROBE_OVERRIDE
- bool "Enable BPF programs to override a kprobed function"
- depends on BPF_EVENTS
- depends on FUNCTION_ERROR_INJECTION
- default n
- help
- Allows BPF to override the execution of a probed function and
- set a different return value. This is used for error injection.
- config FTRACE_MCOUNT_RECORD
- def_bool y
- depends on DYNAMIC_FTRACE
- depends on HAVE_FTRACE_MCOUNT_RECORD
- config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
- bool
- depends on FTRACE_MCOUNT_RECORD
- config FTRACE_MCOUNT_USE_CC
- def_bool y
- depends on $(cc-option,-mrecord-mcount)
- depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
- depends on FTRACE_MCOUNT_RECORD
- config FTRACE_MCOUNT_USE_OBJTOOL
- def_bool y
- depends on HAVE_OBJTOOL_MCOUNT
- depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
- depends on !FTRACE_MCOUNT_USE_CC
- depends on FTRACE_MCOUNT_RECORD
- select OBJTOOL
- config FTRACE_MCOUNT_USE_RECORDMCOUNT
- def_bool y
- depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
- depends on !FTRACE_MCOUNT_USE_CC
- depends on !FTRACE_MCOUNT_USE_OBJTOOL
- depends on FTRACE_MCOUNT_RECORD
- config TRACING_MAP
- bool
- depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
- help
- tracing_map is a special-purpose lock-free map for tracing,
- separated out as a stand-alone facility in order to allow it
- to be shared between multiple tracers. It isn't meant to be
- generally used outside of that context, and is normally
- selected by tracers that use it.
- config SYNTH_EVENTS
- bool "Synthetic trace events"
- select TRACING
- select DYNAMIC_EVENTS
- default n
- help
- Synthetic events are user-defined trace events that can be
- used to combine data from other trace events or in fact any
- data source. Synthetic events can be generated indirectly
- via the trace() action of histogram triggers or directly
- by way of an in-kernel API.
- See Documentation/trace/events.rst or
- Documentation/trace/histogram.rst for details and examples.
- If in doubt, say N.
- config USER_EVENTS
- bool "User trace events"
- select TRACING
- select DYNAMIC_EVENTS
- depends on BROKEN || COMPILE_TEST # API needs to be straighten out
- help
- User trace events are user-defined trace events that
- can be used like an existing kernel trace event. User trace
- events are generated by writing to a tracefs file. User
- processes can determine if their tracing events should be
- generated by memory mapping a tracefs file and checking for
- an associated byte being non-zero.
- If in doubt, say N.
- config HIST_TRIGGERS
- bool "Histogram triggers"
- depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
- select TRACING_MAP
- select TRACING
- select DYNAMIC_EVENTS
- select SYNTH_EVENTS
- default n
- help
- Hist triggers allow one or more arbitrary trace event fields
- to be aggregated into hash tables and dumped to stdout by
- reading a debugfs/tracefs file. They're useful for
- gathering quick and dirty (though precise) summaries of
- event activity as an initial guide for further investigation
- using more advanced tools.
- Inter-event tracing of quantities such as latencies is also
- supported using hist triggers under this option.
- See Documentation/trace/histogram.rst.
- If in doubt, say N.
- config TRACE_EVENT_INJECT
- bool "Trace event injection"
- depends on TRACING
- help
- Allow user-space to inject a specific trace event into the ring
- buffer. This is mainly used for testing purpose.
- If unsure, say N.
- config TRACEPOINT_BENCHMARK
- bool "Add tracepoint that benchmarks tracepoints"
- help
- This option creates the tracepoint "benchmark:benchmark_event".
- When the tracepoint is enabled, it kicks off a kernel thread that
- goes into an infinite loop (calling cond_resched() to let other tasks
- run), and calls the tracepoint. Each iteration will record the time
- it took to write to the tracepoint and the next iteration that
- data will be passed to the tracepoint itself. That is, the tracepoint
- will report the time it took to do the previous tracepoint.
- The string written to the tracepoint is a static string of 128 bytes
- to keep the time the same. The initial string is simply a write of
- "START". The second string records the cold cache time of the first
- write which is not added to the rest of the calculations.
- As it is a tight loop, it benchmarks as hot cache. That's fine because
- we care most about hot paths that are probably in cache already.
- An example of the output:
- START
- first=3672 [COLD CACHED]
- last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
- last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
- last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
- last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
- last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
- last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
- config RING_BUFFER_BENCHMARK
- tristate "Ring buffer benchmark stress tester"
- depends on RING_BUFFER
- help
- This option creates a test to stress the ring buffer and benchmark it.
- It creates its own ring buffer such that it will not interfere with
- any other users of the ring buffer (such as ftrace). It then creates
- a producer and consumer that will run for 10 seconds and sleep for
- 10 seconds. Each interval it will print out the number of events
- it recorded and give a rough estimate of how long each iteration took.
- It does not disable interrupts or raise its priority, so it may be
- affected by processes that are running.
- If unsure, say N.
- config TRACE_EVAL_MAP_FILE
- bool "Show eval mappings for trace events"
- depends on TRACING
- help
- The "print fmt" of the trace events will show the enum/sizeof names
- instead of their values. This can cause problems for user space tools
- that use this string to parse the raw data as user space does not know
- how to convert the string to its value.
- To fix this, there's a special macro in the kernel that can be used
- to convert an enum/sizeof into its value. If this macro is used, then
- the print fmt strings will be converted to their values.
- If something does not get converted properly, this option can be
- used to show what enums/sizeof the kernel tried to convert.
- This option is for debugging the conversions. A file is created
- in the tracing directory called "eval_map" that will show the
- names matched with their values and what trace event system they
- belong too.
- Normally, the mapping of the strings to values will be freed after
- boot up or module load. With this option, they will not be freed, as
- they are needed for the "eval_map" file. Enabling this option will
- increase the memory footprint of the running kernel.
- If unsure, say N.
- config FTRACE_RECORD_RECURSION
- bool "Record functions that recurse in function tracing"
- depends on FUNCTION_TRACER
- help
- All callbacks that attach to the function tracing have some sort
- of protection against recursion. Even though the protection exists,
- it adds overhead. This option will create a file in the tracefs
- file system called "recursed_functions" that will list the functions
- that triggered a recursion.
- This will add more overhead to cases that have recursion.
- If unsure, say N
- config FTRACE_RECORD_RECURSION_SIZE
- int "Max number of recursed functions to record"
- default 128
- depends on FTRACE_RECORD_RECURSION
- help
- This defines the limit of number of functions that can be
- listed in the "recursed_functions" file, that lists all
- the functions that caused a recursion to happen.
- This file can be reset, but the limit can not change in
- size at runtime.
- config RING_BUFFER_RECORD_RECURSION
- bool "Record functions that recurse in the ring buffer"
- depends on FTRACE_RECORD_RECURSION
- # default y, because it is coupled with FTRACE_RECORD_RECURSION
- default y
- help
- The ring buffer has its own internal recursion. Although when
- recursion happens it wont cause harm because of the protection,
- but it does cause an unwanted overhead. Enabling this option will
- place where recursion was detected into the ftrace "recursed_functions"
- file.
- This will add more overhead to cases that have recursion.
- config GCOV_PROFILE_FTRACE
- bool "Enable GCOV profiling on ftrace subsystem"
- depends on GCOV_KERNEL
- help
- Enable GCOV profiling on ftrace subsystem for checking
- which functions/lines are tested.
- If unsure, say N.
- Note that on a kernel compiled with this config, ftrace will
- run significantly slower.
- config FTRACE_SELFTEST
- bool
- config FTRACE_STARTUP_TEST
- bool "Perform a startup test on ftrace"
- depends on GENERIC_TRACER
- select FTRACE_SELFTEST
- help
- This option performs a series of startup tests on ftrace. On bootup
- a series of tests are made to verify that the tracer is
- functioning properly. It will do tests on all the configured
- tracers of ftrace.
- config EVENT_TRACE_STARTUP_TEST
- bool "Run selftest on trace events"
- depends on FTRACE_STARTUP_TEST
- default y
- help
- This option performs a test on all trace events in the system.
- It basically just enables each event and runs some code that
- will trigger events (not necessarily the event it enables)
- This may take some time run as there are a lot of events.
- config EVENT_TRACE_TEST_SYSCALLS
- bool "Run selftest on syscall events"
- depends on EVENT_TRACE_STARTUP_TEST
- help
- This option will also enable testing every syscall event.
- It only enables the event and disables it and runs various loads
- with the event enabled. This adds a bit more time for kernel boot
- up since it runs this on every system call defined.
- TBD - enable a way to actually call the syscalls as we test their
- events
- config FTRACE_SORT_STARTUP_TEST
- bool "Verify compile time sorting of ftrace functions"
- depends on DYNAMIC_FTRACE
- depends on BUILDTIME_MCOUNT_SORT
- help
- Sorting of the mcount_loc sections that is used to find the
- where the ftrace knows where to patch functions for tracing
- and other callbacks is done at compile time. But if the sort
- is not done correctly, it will cause non-deterministic failures.
- When this is set, the sorted sections will be verified that they
- are in deed sorted and will warn if they are not.
- If unsure, say N
- config RING_BUFFER_STARTUP_TEST
- bool "Ring buffer startup self test"
- depends on RING_BUFFER
- help
- Run a simple self test on the ring buffer on boot up. Late in the
- kernel boot sequence, the test will start that kicks off
- a thread per cpu. Each thread will write various size events
- into the ring buffer. Another thread is created to send IPIs
- to each of the threads, where the IPI handler will also write
- to the ring buffer, to test/stress the nesting ability.
- If any anomalies are discovered, a warning will be displayed
- and all ring buffers will be disabled.
- The test runs for 10 seconds. This will slow your boot time
- by at least 10 more seconds.
- At the end of the test, statics and more checks are done.
- It will output the stats of each per cpu buffer. What
- was written, the sizes, what was read, what was lost, and
- other similar details.
- If unsure, say N
- config RING_BUFFER_VALIDATE_TIME_DELTAS
- bool "Verify ring buffer time stamp deltas"
- depends on RING_BUFFER
- help
- This will audit the time stamps on the ring buffer sub
- buffer to make sure that all the time deltas for the
- events on a sub buffer matches the current time stamp.
- This audit is performed for every event that is not
- interrupted, or interrupting another event. A check
- is also made when traversing sub buffers to make sure
- that all the deltas on the previous sub buffer do not
- add up to be greater than the current time stamp.
- NOTE: This adds significant overhead to recording of events,
- and should only be used to test the logic of the ring buffer.
- Do not use it on production systems.
- Only say Y if you understand what this does, and you
- still want it enabled. Otherwise say N
- config MMIOTRACE_TEST
- tristate "Test module for mmiotrace"
- depends on MMIOTRACE && m
- help
- This is a dumb module for testing mmiotrace. It is very dangerous
- as it will write garbage to IO memory starting at a given address.
- However, it should be safe to use on e.g. unused portion of VRAM.
- Say N, unless you absolutely know what you are doing.
- config PREEMPTIRQ_DELAY_TEST
- tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
- depends on m
- help
- Select this option to build a test module that can help test latency
- tracers by executing a preempt or irq disable section with a user
- configurable delay. The module busy waits for the duration of the
- critical section.
- For example, the following invocation generates a burst of three
- irq-disabled critical sections for 500us:
- modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
- What's more, if you want to attach the test on the cpu which the latency
- tracer is running on, specify cpu_affinity=cpu_num at the end of the
- command.
- If unsure, say N
- config SYNTH_EVENT_GEN_TEST
- tristate "Test module for in-kernel synthetic event generation"
- depends on SYNTH_EVENTS
- help
- This option creates a test module to check the base
- functionality of in-kernel synthetic event definition and
- generation.
- To test, insert the module, and then check the trace buffer
- for the generated sample events.
- If unsure, say N.
- config KPROBE_EVENT_GEN_TEST
- tristate "Test module for in-kernel kprobe event generation"
- depends on KPROBE_EVENTS
- help
- This option creates a test module to check the base
- functionality of in-kernel kprobe event definition.
- To test, insert the module, and then check the trace buffer
- for the generated kprobe events.
- If unsure, say N.
- config HIST_TRIGGERS_DEBUG
- bool "Hist trigger debug support"
- depends on HIST_TRIGGERS
- help
- Add "hist_debug" file for each event, which when read will
- dump out a bunch of internal details about the hist triggers
- defined on that event.
- The hist_debug file serves a couple of purposes:
- - Helps developers verify that nothing is broken.
- - Provides educational information to support the details
- of the hist trigger internals as described by
- Documentation/trace/histogram-design.rst.
- The hist_debug output only covers the data structures
- related to the histogram definitions themselves and doesn't
- display the internals of map buckets or variable values of
- running histograms.
- If unsure, say N.
- source "kernel/trace/rv/Kconfig"
- endif # FTRACE
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