diff options
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 116 |
1 files changed, 57 insertions, 59 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d006554888dc..60e2ce0181ee 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -12,39 +12,37 @@ config NOP_TRACER config HAVE_FTRACE_NMI_ENTER bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt config HAVE_FUNCTION_TRACER bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt config HAVE_FUNCTION_GRAPH_TRACER bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt 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. + See Documentation/trace/ftrace-design.txt config HAVE_FUNCTION_TRACE_MCOUNT_TEST bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt config HAVE_DYNAMIC_FTRACE bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt config HAVE_FTRACE_MCOUNT_RECORD bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt config HAVE_HW_BRANCH_TRACER bool @@ -52,7 +50,7 @@ config HAVE_HW_BRANCH_TRACER config HAVE_SYSCALL_TRACEPOINTS bool help - See Documentation/trace/ftrace-implementation.txt + See Documentation/trace/ftrace-design.txt config TRACER_MAX_TRACE bool @@ -83,7 +81,7 @@ config RING_BUFFER_ALLOW_SWAP # 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. +# hiding of the automatic options. config TRACING bool @@ -119,7 +117,7 @@ menuconfig FTRACE bool "Tracers" default y if DEBUG_KERNEL help - Enable the kernel tracing infrastructure. + Enable the kernel tracing infrastructure. if FTRACE @@ -133,7 +131,7 @@ config FUNCTION_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 + 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 @@ -150,7 +148,7 @@ config FUNCTION_GRAPH_TRACER 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 + the return value. This is done by setting the current return address on the current task structure into a stack of calls. @@ -173,7 +171,7 @@ config IRQSOFF_TRACER echo 0 > /sys/kernel/debug/tracing/tracing_max_latency - (Note that kernel size and overhead increases with this option + (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.) @@ -186,7 +184,7 @@ config PREEMPT_TRACER select TRACER_MAX_TRACE select RING_BUFFER_ALLOW_SWAP help - This option measures the time spent in preemption off critical + This option measures the time spent in preemption-off critical sections, with microsecond accuracy. The default measurement method is a maximum search, which is @@ -195,7 +193,7 @@ config PREEMPT_TRACER echo 0 > /sys/kernel/debug/tracing/tracing_max_latency - (Note that kernel size and overhead increases with this option + (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.) @@ -222,7 +220,7 @@ config ENABLE_DEFAULT_TRACERS depends on !GENERIC_TRACER select TRACING help - This tracer hooks to various trace points in the kernel + 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. @@ -265,19 +263,19 @@ choice 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 + The "all branch" profiler will profile every if-statement in the kernel. This profiler will also enable the likely/unlikely - profiler as well. + profiler. - Either of the above profilers add a bit of overhead to the system. - If unsure choose "No branch profiling". + 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. + 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" @@ -288,7 +286,7 @@ config PROFILE_ANNOTATED_BRANCHES /sys/kernel/debug/tracing/profile_annotated_branch - Note: this will add a significant overhead, only turn this + 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 @@ -305,7 +303,7 @@ config PROFILE_ALL_BRANCHES This configuration, when enabled, will impose a great overhead on the system. This should only be enabled when the system - is to be analyzed + is to be analyzed in much detail. endchoice config TRACING_BRANCHES @@ -335,7 +333,7 @@ config POWER_TRACER depends on X86 select GENERIC_TRACER help - This tracer helps developers to analyze and optimize the kernels + This tracer helps developers to analyze and optimize the kernel's power management decisions, specifically the C-state and P-state behavior. @@ -391,14 +389,14 @@ config HW_BRANCH_TRACER 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. + 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 + 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 @@ -417,15 +415,15 @@ config WORKQUEUE_TRACER bool "Trace workqueues" select GENERIC_TRACER help - The workqueue tracer provides some statistical informations + The workqueue tracer provides some statistical information 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. + to evaluate the amount of work each of them has to perform. For example it can help a developer to decide whether he should - choose a per cpu workqueue instead of a singlethreaded one. + choose a per-cpu workqueue instead of a singlethreaded one. config BLK_DEV_IO_TRACE - bool "Support for tracing block io actions" + bool "Support for tracing block IO actions" depends on SYSFS depends on BLOCK select RELAY @@ -456,15 +454,15 @@ config KPROBE_EVENT select TRACING 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.txt - for more details. + This allows the user to add tracing events (similar to tracepoints) + on the fly via the ftrace interface. See + Documentation/trace/kprobetrace.txt 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. + 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 DYNAMIC_FTRACE bool "enable/disable ftrace tracepoints dynamically" @@ -472,32 +470,32 @@ config DYNAMIC_FTRACE 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 option will modify all the calls to ftrace dynamically + (will patch them out of the binary image and replace 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. + 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. + 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. + 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_stats directory; this file shows the list of functions that + have been hit and their counters. - If in doubt, say N + If in doubt, say N. config FTRACE_MCOUNT_RECORD def_bool y @@ -556,8 +554,8 @@ 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 + 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 @@ -566,7 +564,7 @@ config RING_BUFFER_BENCHMARK It does not disable interrupts or raise its priority, so it may be affected by processes that are running. - If unsure, say N + If unsure, say N. endif # FTRACE |