forked from
anil.recoil.org/monopam-myspace
My aggregated monorepo of OCaml code, automaintained
Buffer HTML output to avoid per-chunk channel mutex overhead
Format.formatter_of_out_channel writes to the channel on every buffer
flush. Each write takes the OCaml multicore channel mutex (trylock +
unlock), which callgrind showed at ~3% self-time on html-generate.
Accumulate output in a Buffer and write the whole file in one call
at the end. The mutex is taken once per page instead of many times.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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odoc/src/utils/odoc_utils.ml
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odoc/src/utils/odoc_utils.ml
···
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let with_open_out_bin fname f =
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_with_resource (open_out_bin fname) ~close:close_out_noerr f
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(** Like [with_open_out] but operate on a [Format] buffer. *)
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(** Like [with_open_out] but operate on a [Format] buffer.
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Uses a Buffer to accumulate output and writes it to the file in one
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go at the end. This avoids per-chunk channel mutex acquisition in
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the multicore runtime. *)
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let with_formatter_out fname f =
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with_open_out fname (fun oc -> f (Format.formatter_of_out_channel oc))
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let buf = Buffer.create 65536 in
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let fmt = Format.formatter_of_buffer buf in
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let result = f fmt in
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Format.pp_print_flush fmt ();
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with_open_out fname (fun oc -> Buffer.output_buffer oc buf);
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result
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(** Shortcuts for composing [with_open_*] functions and [Marshal]. *)
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let marshal fname v =