[safe/jmp/linux-2.6] / kernel / trace / Kconfig

#
# Architectures that offer an FUNCTION_TRACER implementation should
#  select HAVE_FUNCTION_TRACER:
#

config USER_STACKTRACE_SUPPORT
        bool

config NOP_TRACER
        bool

config HAVE_FTRACE_NMI_ENTER
        bool

config HAVE_FUNCTION_TRACER
        bool

config HAVE_FUNCTION_GRAPH_TRACER
        bool

config HAVE_FUNCTION_GRAPH_FP_TEST
        bool
        help
         An arch may pass in a unique value (frame pointer) to both the
         entering and exiting of a function. On exit, the value is compared
         and if it does not match, then it will panic the kernel.

config HAVE_FUNCTION_TRACE_MCOUNT_TEST
        bool
        help
         This gets selected when the arch tests the function_trace_stop
         variable at the mcount call site. Otherwise, this variable
         is tested by the called function.

config HAVE_DYNAMIC_FTRACE
        bool

config HAVE_FTRACE_MCOUNT_RECORD
        bool

config HAVE_HW_BRANCH_TRACER
        bool

config HAVE_FTRACE_SYSCALLS
        bool

config TRACER_MAX_TRACE
        bool

config RING_BUFFER
        bool

config FTRACE_NMI_ENTER
       bool
       depends on HAVE_FTRACE_NMI_ENTER
       default y

config EVENT_TRACING
        select CONTEXT_SWITCH_TRACER
        bool

config CONTEXT_SWITCH_TRACER
        select MARKERS
        bool

# 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
# hidding of the automatic options options.

config TRACING
        bool
        select DEBUG_FS
        select RING_BUFFER
        select STACKTRACE if STACKTRACE_SUPPORT
        select TRACEPOINTS
        select NOP_TRACER
        select BINARY_PRINTF
        select EVENT_TRACING

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
        # PPC32 has no irqflags tracing support, but it can use most of the
        # tracers anyway, they were tested to build and work. Note that new
        # exceptions to this list aren't welcomed, better implement the
        # irqflags tracing for your architecture.
        depends on TRACE_IRQFLAGS_SUPPORT || PPC32
        depends on STACKTRACE_SUPPORT
        default y

if TRACING_SUPPORT

menuconfig FTRACE
        bool "Tracers"
        default y if DEBUG_KERNEL
        help
         Enable the kernel tracing infrastructure.

if FTRACE

config FUNCTION_TRACER
        bool "Kernel Function Tracer"
        depends on HAVE_FUNCTION_TRACER
        select FRAME_POINTER
        select KALLSYMS
        select GENERIC_TRACER
        select CONTEXT_SWITCH_TRACER
        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 to 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.

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 IRQSOFF_TRACER
        bool "Interrupts-off Latency Tracer"
        default n
        depends on TRACE_IRQFLAGS_SUPPORT
        depends on GENERIC_TIME
        select TRACE_IRQFLAGS
        select GENERIC_TRACER
        select TRACER_MAX_TRACE
        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 increases 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 GENERIC_TIME
        depends on PREEMPT
        select GENERIC_TRACER
        select TRACER_MAX_TRACE
        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 increases with this option
          enabled. This option and the irqs-off timing option can be
          used together or separately.)

config SYSPROF_TRACER
        bool "Sysprof Tracer"
        depends on X86
        select GENERIC_TRACER
        select CONTEXT_SWITCH_TRACER
        help
          This tracer provides the trace needed by the 'Sysprof' userspace
          tool.

config SCHED_TRACER
        bool "Scheduling Latency Tracer"
        select GENERIC_TRACER
        select CONTEXT_SWITCH_TRACER
        select TRACER_MAX_TRACE
        help
          This tracer tracks the latency of the highest priority task
          to be scheduled in, starting from the point it has woken up.

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_FTRACE_SYSCALLS
        select GENERIC_TRACER
        select KALLSYMS
        help
          Basic tracer to catch the syscall entry and exit events.

config BOOT_TRACER
        bool "Trace boot initcalls"
        select GENERIC_TRACER
        select CONTEXT_SWITCH_TRACER
        help
          This tracer helps developers to optimize boot times: it records
          the timings of the initcalls and traces key events and the identity
          of tasks that can cause boot delays, such as context-switches.

          Its aim is to be parsed by the scripts/bootgraph.pl tool to
          produce pretty graphics about boot inefficiencies, giving a visual
          representation of the delays during initcalls - but the raw
          /debug/tracing/trace text output is readable too.

          You must pass in initcall_debug and ftrace=initcall to the kernel
          command line to enable this on bootup.

config SKB_SOURCES_TRACER
        bool "Trace skb source information"
        depends on NET
        select GENERIC_TRACER
        help
           This tracer helps developers/sysadmins correlate skb allocation and
           consumption.  The idea being that some processes will primarily consume data
           that was allocated on certain numa nodes.  By being able to visualize which
           nodes the data was allocated on, a sysadmin or developer can optimize the
           scheduling of those processes to cut back on cross node chatter.

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 as well.

         Either of the above profilers add 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 the the likely and unlikely macros
          in the kernel. It will display the results in:

          /sys/kernel/debug/tracing/profile_annotated_branch

          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"
        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/profile_branch

          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
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 POWER_TRACER
        bool "Trace power consumption behavior"
        depends on X86
        select GENERIC_TRACER
        help
          This tracer helps developers to analyze and optimize the kernels
          power management decisions, specifically the C-state and P-state
          behavior.


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 HW_BRANCH_TRACER
        depends on HAVE_HW_BRANCH_TRACER
        bool "Trace hw branches"
        select GENERIC_TRACER
        help
          This tracer records all branches on the system in a circular
          buffer giving access to the last N branches for each cpu.

config KMEMTRACE
        bool "Trace SLAB allocations"
        select GENERIC_TRACER
        help
          kmemtrace provides tracing for slab allocator functions, such as
          kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
          data is then fed to the userspace application in order to analyse
          allocation hotspots, internal fragmentation and so on, making it
          possible to see how well an allocator performs, as well as debug
          and profile kernel code.

          This requires an userspace application to use. See
          Documentation/trace/kmemtrace.txt for more information.

          Saying Y will make the kernel somewhat larger and slower. However,
          if you disable kmemtrace at run-time or boot-time, the performance
          impact is minimal (depending on the arch the kernel is built for).

          If unsure, say N.

config WORKQUEUE_TRACER
        bool "Trace workqueues"
        select GENERIC_TRACER
        help
          The workqueue tracer provides some statistical informations
          about each cpu workqueue thread such as the number of the
          works inserted and executed since their creation. It can help
          to evaluate the amount of work each of them have to perform.
          For example it can help a developer to decide whether he should
          choose a per cpu workqueue instead of a singlethreaded one.

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 DYNAMIC_FTRACE
        bool "enable/disable ftrace tracepoints dynamically"
        depends on FUNCTION_TRACER
        depends on HAVE_DYNAMIC_FTRACE
        default y
        help
         This option will modify all the calls to ftrace dynamically
         (will patch them out of the binary image and replaces them
         with a No-Op instruction) as they are called. A table is
         created to dynamically enable them again.

         This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
         has native performance as long as no tracing is active.

         The changes to the code are done by a kernel thread that
         wakes up once a second and checks to see if any ftrace calls
         were made. If so, it runs stop_machine (stops all CPUS)
         and modifies the code to jump over the call to ftrace.

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 file in the trace_stats
         directory called functions, that show the list of functions that
         have been hit and their counters.

         If in doubt, say N

config FTRACE_MCOUNT_RECORD
        def_bool y
        depends on DYNAMIC_FTRACE
        depends on HAVE_FTRACE_MCOUNT_RECORD

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 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.txt.
          If you are not helping to develop drivers, 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 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 bench mark it.
          It creates its own ring buffer such that it will not interfer 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

endif # FTRACE

endif # TRACING_SUPPORT