wehub-resource-sync
71 lines
2.9 KiB
OCaml
71 lines
2.9 KiB
OCaml
open! Core
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(** Write to a file using synchronous writes, not suitable for low latency applications. *)
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val direct_file_destination
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: ?buffer_size:int
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-> filename:string
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-> unit
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-> (module Writer_intf.Destination)
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(** Write to a zstd compressed file using synchronous writes, not suitable for low latency
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applications. *)
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val zstd_file_destination
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: ?buffer_size:int
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-> filename:string
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-> unit
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-> (module Writer_intf.Destination)
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(** Write to a gzip compressed file using synchronous writes, not suitable for low latency
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applications. *)
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val gzip_file_destination
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: ?buffer_size:int
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-> filename:string
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-> unit
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-> (module Writer_intf.Destination)
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(** Write to a file in some way with the best available performance. [format] defaults to
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[Uncompressed]. *)
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val file_destination : ?file_format:Writer_intf.File_format.t -> filename:string -> unit -> (module Writer_intf.Destination)
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(** Write to a provided [Iobuf.t], throws an exception if the buffer runs out of space.
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Mostly intended for use in tests. After the [Destination] is closed, sets the window
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of the [Iobuf.t] to the data written. *)
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val iobuf_destination
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: (read_write, Iobuf.seek, Iobuf.global) Iobuf.t
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-> (module Writer_intf.Destination)
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(** Creates a new buffer, which is reset and reused on every call to [next_buf],
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effectively dropping all the previously-recorded content, as the name suggests.
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Useful for performance benchmarking or having trace
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events be ignored without growing an in-memory log.
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[len] is the length of the buffer and can be tuned to simulate different cache
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characteristics in a benchmark or avoid using much memory when ignoring events.
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If [touch_memory] is true, the memory will be written over to ensure all the
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memory is paged in, to reduce benchmark variance. *)
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val black_hole_destination
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: len:int
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-> touch_memory:bool
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-> (module Writer_intf.Destination)
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(** Starts by keeping events in internal memory buffers. After [set_destination] is called
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it will copy any buffered events into the new destination upon the next buffer switch,
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then provide a buffer directly from the newly set destination.
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This is intended for use with a global trace writer which needs to be available from
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initialization time, before anything like a trace file has been set up.
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It also provides one other feature not guaranteed by other destinations, which is that
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writes after [close] is called will be ignored without error. This behavior was chosen
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so that when adding performance instrumentation to functions, users don't have to
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worry about those functions potentially being called in late stages of application
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shutdown after a trace file has been closed. *)
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module Buffer_until_initialized : sig
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type t
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val create : unit -> t
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val set_destination : t -> (module Writer_intf.Destination) -> unit
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val to_destination : t -> (module Writer_intf.Destination)
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end
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