thread_pool_count = 0 (default) keeps handlers inline on the loop
thread — the measured fast path (BENCH-HTTPZ.md). N > 0 dispatches
each parsed request to a std.thread Pool of N workers, completing the
httpz two-pool shape: the connection freezes as CONN_HANDLING (no
reads, growth, eviction, or recycling — the worker borrows views into
its read buffer), the worker runs the handler under a per-job arena
and serializes into job-owned bytes, the completion queues under the
PoolState mutex, and the loop wakes through the new std.event wake
channel (kqueue EVFILT_USER + EV_CLEAR; the epoll twin maps to
eventfd), attaches the response, compacts the buffer, and resumes
keep-alive/pipeline handling. A full backlog sheds with 503. Stale
completions (generation mismatch after close) are dropped. Pool mode
requires the server's constructing allocator to be thread-safe
(GPA/malloc), documented on the knob.
PoolState lives behind a heap pointer (it embeds a Mutex and is shared
with workers; the Server struct itself is returned by value).
serialize_response/run_handler_job share one serialize_bytes.
examples/1633 gains the pooled section (GET, body echo, 404 across
worker threads) plus the loop-wake path exercised end to end; AOT run
five times. examples/1632 unchanged but the Event struct gains `user`.
read_buf_cap is now the per-request LIMIT, not a preallocation: slots
start at 16K, double when full (one-step sizing when a Content-Length
declares the body), and keep their grown capacity for slot reuse. At
the limit the refusal distinguishes oversized headers (431) from an
oversized body (413). Unblocks A1: distd accepts multi-hundred-MB
artifact uploads — preallocating that per slot was never an option.
examples/1633 adds a body past the initial capacity echoing intact.
The httpz shape, one worker, handlers inline over the std.event Loop:
nonblocking accept, per-connection state machine (reading -> writing ->
keepalive/close) with incremental parsing (request line, headers,
Content-Length body), partial-write continuation via on-demand write
interest, pipelined-request draining, and timeouts as EVICTION —
request-delivery and keepalive-idle deadlines on the monotonic clock,
checked after I/O each tick. Keep-alive is the HTTP/1.1 default;
Connection header, HTTP/1.0, or the per-connection request_count cap
turn it off. Config mirrors httpz: port/backlog/max_conn/read_buf_cap/
timeout_request_ms/timeout_keepalive_ms/request_count.
API: Server.init(cfg, handler) + tick(max_wait_ms); run() is the
forever-tick loop. tick makes the server drivable single-threaded —
examples/1633 runs a live server and its client sockets in ONE thread,
pinning: GET with keep-alive, actual connection reuse, the request cap
answering Connection: close then EOF, POST body echo, 404 routing, and
a half-header client evicted at the request deadline while a healthy
client keeps being served. Verified under sx run AND sx build.
Connection slots and read buffers are reused across connections
(httpz's min_conn/buffer-pool spirit); response buffers are allocated
per response and freed on completion. Serialization happens while
request views are valid, the served bytes are compacted, and only then
does sending start — write_more's pipelining check must see only the
remainder. The std.sx barrel carries http; .ir snapshot regen is the
usual mechanical renumbering.
S7b adds worker counts + the handler thread pool (needs C2/S6); the
epoll backend activates with the linux target (S4/S7c).
