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libmicrohttpd 1.0.10: header values parsed in a tight loop (a JWT costs a third) - #27
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…e tight loop A 700-byte Authorization header cost 0.86 us of a 10 us PATCH in get_req_headers; with the patch 0.31 us. Line ends, folding, bare CR/LF and the client discipline levels go through MHD's loop as before; libmicrohttpd's make check: 180/180. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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tools/mhd/patches/1.0.10/0001-header-value-fastpath.patch- applied bymhdBuild.sh(CI image, published image, runners, workstations).Why: profiling coraine's PATCH with an access token, the token's cost is MHD's header parser:
get_req_header()reads a value one character at a time, re-testing CR/LF/SP/HTAB/NUL and writingws_startback to the connection for each.get_req_headerswent from 2.0 % to 9.2 % of the broker's time with a 696-byteAuthorization: Bearer <JWT>.The patch: after a value's first character, the following characters above SP are processed exactly as it is - they are skipped in a compare-only loop. CR, LF, SP, HTAB, NUL and other control characters stop it and take MHD's path unchanged (line end, obs-fold, bare CR/LF, the client discipline levels). Under
MHD_FAVOR_SMALL_CODEthe release's code is compiled.Measured (coraine on 1 core, corDB, PATCH c50, ABBA stock/patched/patched/stock, 12 s each):
libmicrohttpd's own
make checkon the patched tree: 180 of 180 pass. coraine's functests on it (debug build, mongoc, the patched library throughLD_LIBRARY_PATH, verified in a running broker's maps): 811 of 811 pass (2026-10-13, after the merge).Upstream: not posted - a draft for Karlson2k/libmicrohttpd waits for KZ.
Merge after: nothing
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