package tracing

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in-package search v0.2.0

tracing
- Library tracing
  - Tracing
    
    Trace
    
    Thread
    
    Arg
    
    Async
    
    Expert
    
    Flow
    
    Queue_to_spans
    
    Parser
    
    Time_ns
    
    Event_type
    
    Thread
    
    Parse_error
    
    Warnings
    
    String_index
    
    Thread_index
    
    Event_arg
    
    Event
    
    Record
    
    Record_writer
    
    Buffer
- Library tracing.tool_output
  - Tracing_tool_output
    
    Serve
- Library tracing.tracing_destinations_unix
  - Tracing_destinations_unix
    
    Destination
- Library tracing.tracing_zero
  - Tracing_zero
    
    Writer
    
    Tick_translation
    
    String_id
    
    Thread_id
    
    Arg_types
    
    Write_arg
    
    Expert
    
    Destination
    
    Event_type
    
    Write_arg_unchecked
    
    Writer_intf
    
    Destination
    
    Arg_writers
    
    Tick_translation
    
    S
    
    Tick_translation
    
    String_id
    
    Thread_id
    
    Arg_types
    
    Write_arg
    
    Expert
    
    Destination
    
    Event_type
    
    Write_arg_unchecked
    
    Destinations
    
    Buffer_until_initialized
- Sources
  - tracing
    
    buffer.ml
    
    flow.ml
    
    parser.ml
    
    parser_intf.ml
    
    queue_to_spans.ml
    
    record_writer.ml
    
    trace.ml
    
    trace_intf.ml
    
    tracing.ml
    
    tracing__.ml
    
    util.ml
  - tracing.tool_output
    
    tool_output_intf.ml
    
    tracing_tool_output.ml
    
    tracing_tool_output__.ml
  - tracing.tracing_destinations_unix
    
    tracing_destinations_unix.ml
  - tracing.tracing_zero
    
    destinations.ml
    
    tracing_zero.ml
    
    tracing_zero__.ml
    
    writer.ml
    
    writer_intf.ml

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Source

Module `Writer.Expert`Source

Sourcemodule type Destination = Writer_intf.Destination

val create : 
  ?num_temp_strs:int ->
  destination:(module Destination) ->
  unit ->
  t

Source

val create_no_header : 
  ?num_temp_strs:int ->
  destination:(module Destination) ->
  unit ->
  t

Creates writer without writing a FXT file header to the destination.

Sourceval set_destination : t -> destination:(module Destination) -> unit

Switches destination for future data. Use with care; does not reset any state.

Sourceval write_bytes : t -> bytes:Core.Bytes.t -> unit

Writes raw byte stream to the current destination.

Sourceval write_iobuf : t -> buf:(Core.read, Iobuf.seek) Iobuf.t -> unit

Writes raw byte stream to the current destination.

Sourceval set_string_slot : t -> slot:int -> string -> String_id.t

Interns a string directly to the specified slot (whereas set_temp_string_slot may shift the index since certain indices are reserved for internal use). Will raise when setting slot 1 to any string other than "process".

Useful for preserving the string ID usage of parsed traces in a way that can lead to exact byte equality after a round trip through parsing and writing.

Sourceval force_switch_buffers : t -> unit

Immediately ask the destination for a new buffer even if the current one isn't full. This is intended for use by the probe infrastructure when a destination for the global writer is initialized.

Sourceval flush : t -> unit

Finish all pending writes to underlying buffer.

This is currently only intended for use by tests.

Sourcetype header

Sourceval set_name : header:header -> name:String_id.t -> header

Sourcemodule Event_type : sig ... end

For use with precompute_header_and_size

Source

val precompute_header : 
  event_type:Event_type.t ->
  extra_words:int ->
  arg_types:Arg_types.t ->
  thread:Thread_id.t ->
  category:String_id.t ->
  name:String_id.t ->
  header

Pre-compose an event header word, for use with write_from_header_with_tsc

Sourceval set_dyn_slot : t -> slot:int -> string -> String_id.t

Interns a string into one of 17 temporary slots reserved for ppx_tracing. These slots are exclusively used to store the category, name, and names of arguments when they cannot be interned globally. Unlike set_temp_string_slot, strings interned to these slots are valid *only* immediately after interning, as the slot will be reused in subsequent probes.

Sourceval write_from_header_with_tsc : t -> header:header -> unit

Write an event using a pre-composed header, and using less safety checking than the normal event writing functions, intended for low-overhead probe instrumentation. Also uses the rdtsc counter for the ticks field, meaning this Writer must have been created with a calibrated ticks_per_second field to have correct timing.

The pre-composition itself saves about 3ns per event. The omission of unnecessary checks saves additional time. Overall in benchmarks this is about 2x faster than using the usual write_* functions, saving about 6ns per event.

The only caller-visible check omission should be that it doesn't check the corectness of arguments, which can result in invalid trace files if the arguments written don't match the header. Users of this function must use Write_arg_unchecked because it doesn't set the necessary state for checking.

Sourceval write_from_header_and_get_tsc : t -> header:header -> Time_stamp_counter.t

Same as write_from_header_with_tsc but but returns ticks. See Tracing.Writer.write_duration_instant.

Sourceval write_tsc : t -> Time_stamp_counter.t -> unit

Unchecked writing of the result of write_from_header_and_get_tsc after the arguments.

Sourceval write_async_id : t -> int -> unit

Unchecked write of a correlation id to complete an async event.

Sourceval set_string_map_allocate_on_intern : t -> enable:bool -> unit

Enables or disables mapping String_id.t to string when interning strings.

Use with caution: Enabling this will allocate upon interning strings and cost an additional Hashtbl.add call.

Sourceval string_of_string_id : t -> String_id.t -> string option

Returns a string represented by the corresponding String_id.t

Source

module Write_arg_unchecked : 
  Writer_intf.Arg_writers with type t := t and type string_id := String_id.t

Unchecked versions of the Write_arg functions that can result in invalid traces.

package tracing

Module Writer.ExpertSource

Module `Writer.Expert`Source