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Diffstat (limited to 'Documentation/libtracefs-options.txt')
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diff --git a/Documentation/libtracefs-options.txt b/Documentation/libtracefs-options.txt new file mode 100644 index 0000000..2c720f2 --- /dev/null +++ b/Documentation/libtracefs-options.txt @@ -0,0 +1,159 @@ +libtracefs(3) +============= + +NAME +---- +tracefs_options - ftrace options, that can be controlled using tracefs library. + +SYNOPSIS +-------- +[verse] +-- +*#include <tracefs.h>* + +enum tracefs_option_id { + *TRACEFS_OPTION_INVALID*, + *TRACEFS_OPTION_ANNOTATE*, + *TRACEFS_OPTION_BIN*, + *TRACEFS_OPTION_BLK_CGNAME*, + *TRACEFS_OPTION_BLK_CGROUP*, + *TRACEFS_OPTION_BLK_CLASSIC*, + *TRACEFS_OPTION_BLOCK*, + *TRACEFS_OPTION_CONTEXT_INFO*, + *TRACEFS_OPTION_DISABLE_ON_FREE*, + *TRACEFS_OPTION_DISPLAY_GRAPH*, + *TRACEFS_OPTION_EVENT_FORK*, + *TRACEFS_OPTION_FGRAPH_ABSTIME*, + *TRACEFS_OPTION_FGRAPH_CPU*, + *TRACEFS_OPTION_FGRAPH_DURATION*, + *TRACEFS_OPTION_FGRAPH_IRQS*, + *TRACEFS_OPTION_FGRAPH_OVERHEAD*, + *TRACEFS_OPTION_FGRAPH_OVERRUN*, + *TRACEFS_OPTION_FGRAPH_PROC*, + *TRACEFS_OPTION_FGRAPH_TAIL*, + *TRACEFS_OPTION_FUNC_STACKTRACE*, + *TRACEFS_OPTION_FUNCTION_FORK*, + *TRACEFS_OPTION_FUNCTION_TRACE*, + *TRACEFS_OPTION_GRAPH_TIME*, + *TRACEFS_OPTION_HEX*, + *TRACEFS_OPTION_IRQ_INFO*, + *TRACEFS_OPTION_LATENCY_FORMAT*, + *TRACEFS_OPTION_MARKERS*, + *TRACEFS_OPTION_OVERWRITE*, + *TRACEFS_OPTION_PAUSE_ON_TRACE*, + *TRACEFS_OPTION_PRINTK_MSG_ONLY*, + *TRACEFS_OPTION_PRINT_PARENT*, + *TRACEFS_OPTION_RAW*, + *TRACEFS_OPTION_RECORD_CMD*, + *TRACEFS_OPTION_RECORD_TGID*, + *TRACEFS_OPTION_SLEEP_TIME*, + *TRACEFS_OPTION_STACKTRACE*, + *TRACEFS_OPTION_SYM_ADDR*, + *TRACEFS_OPTION_SYM_OFFSET*, + *TRACEFS_OPTION_SYM_USEROBJ*, + *TRACEFS_OPTION_TRACE_PRINTK*, + *TRACEFS_OPTION_USERSTACKTRACE*, + *TRACEFS_OPTION_VERBOSE*, +}; +-- + +DESCRIPTION +----------- +This enum contains all ftrace options, that can be manipulated using tracefs library. More detailed +information about each option is available in Documentation/trace/ftrace.rst from the Linux +kernel tree, in the trace_options section. Note that some ftrace options cannot be manipulated by +this library, as they are intended for internal, debug purposes. These options control the tracers +or the trace output. All options have two states - on and off, the default state is different for +each of them. +[verse] +-- +Common options for all tracers: + *TRACEFS_OPTION_INVALID* Not a valid ftrace option, used by the API to indicate an error. + *TRACEFS_OPTION_ANNOTATE* Display when a new CPU buffer started. + *TRACEFS_OPTION_BIN* Display the formats in raw binary. + *TRACEFS_OPTION_CONTEXT_INFO* Show only the event data. Hides the comm, PID, timestamp, CPU, and other useful data. + *TRACEFS_OPTION_BLOCK* When set, reading trace_pipe will not block when polled. + *TRACEFS_OPTION_DISABLE_ON_FREE* When the free_buffer is closed, tracing will stop. + *TRACEFS_OPTION_DISPLAY_GRAPH* When set, the latency tracers will use function graph tracing instead of function tracing. + *TRACEFS_OPTION_EVENT_FORK* When set, tasks with PIDs listed in set_event_pid will have the PIDs of their children added to set_event_pid when those tasks fork. + *TRACEFS_OPTION_FUNCTION_FORK* When set, tasks with PIDs listed in set_ftrace_pid will have the PIDs of their children added to set_ftrace_pid when those tasks fork. + *TRACEFS_OPTION_FUNCTION_TRACE* When enabled, the latency tracers will trace functions. + *TRACEFS_OPTION_HEX* Display numbers in a hexadecimal format. + *TRACEFS_OPTION_IRQ_INFO* Display the interrupt, preempt count, need resched data. + *TRACEFS_OPTION_LATENCY_FORMAT* Display additional information about the latency. + *TRACEFS_OPTION_MARKERS* When set, the trace_marker is enabled - writable (only by root). + *TRACEFS_OPTION_OVERWRITE* Controls what happens when the trace buffer is full. If set, the oldest events are discarded and overwritten. If disabled, then the newest events are discarded. + *TRACEFS_OPTION_PAUSE_ON_TRACE* When set, opening the trace file for read, will pause writing to the ring buffer. When the file is closed, tracing will be enabled again. + *TRACEFS_OPTION_PRINTK_MSG_ONLY* When set, trace_printk()s will only show the format and not their parameters. + *TRACEFS_OPTION_PRINT_PARENT* On function traces, display the calling (parent) function as well as the function being traced. + *TRACEFS_OPTION_RAW* Display raw numbers. + *TRACEFS_OPTION_RECORD_CMD* Save a mapping with a pid and corresponding command. + *TRACEFS_OPTION_RECORD_TGID* Save a mapping with a pid and corresponding Thread Group IDs. + *TRACEFS_OPTION_STACKTRACE* Record a stack trace after any trace event. + *TRACEFS_OPTION_SYM_ADDR* Display the function address as well as the function name. + *TRACEFS_OPTION_SYM_OFFSET* Display not only the function name, but also the offset in the function. + *TRACEFS_OPTION_SYM_USEROBJ* When *TRACEFS_OPTION_USERSTACKTRACE* is set, look up which object the address belongs to, and print the object and a relative address. + *TRACEFS_OPTION_TRACE_PRINTK* Disable trace_printk() from writing into the buffer. + *TRACEFS_OPTION_USERSTACKTRACE* Records a stack trace of the current user space thread after each trace event. + *TRACEFS_OPTION_VERBOSE* When *TRACEFS_OPTION_LATENCY_FORMAT* is enabled, print more detailed information. + +Options, specific to function tracer: + *TRACEFS_OPTION_FUNC_STACKTRACE* Record a stack trace after every function. + +Options, specific to function_graph tracer: + *TRACEFS_OPTION_FGRAPH_ABSTIME* Display the timestamp at each line. + *TRACEFS_OPTION_FGRAPH_CPU* Display the CPU number of the CPU where the trace occurred. + *TRACEFS_OPTION_FGRAPH_DURATION* Display the duration of the amount of time at the end of each function, in microseconds. + *TRACEFS_OPTION_FGRAPH_IRQS* Trace functions that happen inside an interrupt. + *TRACEFS_OPTION_FGRAPH_OVERHEAD* Display a marker if a function takes longer than a certain amount of time. + *TRACEFS_OPTION_FGRAPH_OVERRUN* Display "overrun" of the call graph, in the case of functions missed due to big callstack. + *TRACEFS_OPTION_FGRAPH_PROC* Display the command of each process at every line. + *TRACEFS_OPTION_FGRAPH_TAIL* Display the function name on its return. + *TRACEFS_OPTION_SLEEP_TIME* Account time the task has been scheduled out as part of the function call. + *TRACEFS_OPTION_GRAPH_TIME* Display the time to call nested functions, if function profiler is enabled. + +Options, specific to blk tracer: + *TRACEFS_OPTION_BLK_CGNAME* + *TRACEFS_OPTION_BLK_CGROUP* + *TRACEFS_OPTION_BLK_CLASSIC* Display a more minimalistic output. +-- +FILES +----- +[verse] +-- +*tracefs.h* + Header file to include in order to have access to the library APIs. +*-ltracefs* + Linker switch to add when building a program that uses the library. +-- + +SEE ALSO +-------- +*libtracefs*(3), +*libtraceevent*(3), +*trace-cmd*(1), +_Documentation/trace/ftrace.rst_ from the Linux kernel tree. + +AUTHOR +------ +[verse] +-- +*Steven Rostedt* <rostedt@goodmis.org> +*Tzvetomir Stoyanov* <tz.stoyanov@gmail.com> +-- +REPORTING BUGS +-------------- +Report bugs to <linux-trace-devel@vger.kernel.org> + +LICENSE +------- +libtracefs is Free Software licensed under the GNU LGPL 2.1 + +RESOURCES +--------- +https://git.kernel.org/pub/scm/libs/libtrace/libtracefs.git/ + +COPYING +------- +Copyright \(C) 2021 VMware, Inc. Free use of this software is granted under +the terms of the GNU Public License (GPL). |