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open Bigarray
module Ctf = Eio.Private.Ctf
let timestamper log_buffer ofs =
let ns = Mtime.to_uint64_ns @@ Mtime_clock.now () in
Ctf.BS.set_int64_le log_buffer ofs ns
let mmap_buffer ~size path =
let fd = Unix.(openfile path [O_RDWR; O_CREAT; O_TRUNC] 0o644) in
Unix.set_close_on_exec fd;
Unix.ftruncate fd size;
let ba = array1_of_genarray (Unix.map_file fd char c_layout true [| size |]) in
Unix.close fd;
ba
let with_tracing ?(size=0x100000) path fn =
let buffer = mmap_buffer ~size path in
let trace_config = Ctf.Control.make ~timestamper buffer in
Ctf.Control.start trace_config;
Fun.protect fn ~finally:(fun () -> Ctf.Control.stop trace_config)