examples/http-static-server-cached.lsp — same HTTP server but every
preloaded URL's full HTTP/1.0 response (headers + body) is composed
once at startup and stored in a hash-table, so the per-request
handler is a single hash-table-ref/default. No file->string, no
string-append, no MIME lookup in the hot path.
Config knobs:
*docroot* filesystem root (default "www")
*cache-max* soft cap on cached entries (default 100)
*preload-paths* list of URL paths to pre-fetch at startup
Preload list for lumbda.com: "/", "/style.css", "/whitepaper.pdf",
"/robots.txt", "/404.html" — anything not in the list returns the
cached 404 response (no disk hit). Cache lives pre-snapshot so
heap-restore never reclaims it; RSS stays at the cache size
forever.
Race vs caddy on this laptop (2000 small / 200 large, concurrency 8):
small req/s PDF req/s PDF MiB/s peak RSS
lumbda-www uncached 690 195 495 15.5 MB
lumbda-www cached 686 319 811 7.2 MB
caddy file-server 688 478 1,217 38.9 MB
Cache wins on the PDF: 1.64x faster than uncached, RSS DROPS from
15.5 MB to 7.2 MB because the cached path allocates nothing per
request (all allocation happened pre-snapshot). On small files
already-hot paths mean the cache is a wash — 690 vs 686 is noise.
Caddy still wins 1.5x on the PDF via sendfile(2) zero-copy; we
allocate the 2.67 MB response once at startup and tcp-send it.
Closing the gap further would take a sendfile asm primitive —
separate project. For a minimal static site serving its own
whitepaper, the cached 27 KB asm binary is viable: 319 req/s
and 811 MiB/s with 5x less memory than caddy.
tests/bench-www-race.sh updated to run all three side-by-side
(uncached + cached + caddy) at three ports. Cached server's port
is patched via sed at the entry point so the two lumbda variants
don't collide. PDF byte-integrity checked on all three paths.
