feat: add jemalloc support and incremental hashtable resizing#85
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The INFO reply was sent via the generic send_reply(), which stamps STATUS_SUCCESS as the frame type byte. The client decoder therefore routed INFO through the VALUE path and printed the metrics block quoted with a trailing space, never reaching the dedicated CLIENT_RESPONSE_INFO plain-print branch. Add a dedicated send_info_reply() that emits the CMD_INFO type byte (mirroring send_keys_reply) and switch handle_info_command to use it, so INFO decodes to CLIENT_RESPONSE_INFO and renders as a plain multi-line block. The existing test_info_response_uses_declared_payload_length now reflects the real server wire format instead of an unreachable branch. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
handle_keys_command formatted every entry as "N) key\n", so the payload ended with a newline after the final key. Combined with the client's print_plain_payload_line (which appends its own newline), this rendered a blank trailing line. Treat newlines as separators between entries and send used - 1 bytes to omit the trailing newline. Safe because the else branch only runs when at least one entry was written. Matches the payload shape already asserted by test_keys_response_prints_list_payload. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
- Add FKVS_ENABLE_JEMALLOC CMake option (default OFF) that links fkvs-server against jemalloc; linked unprefixed so it transparently overrides malloc/free with no call-site changes - Add get_allocator_name() reporting the jemalloc version via mallctl, or "system (libc malloc)" otherwise - Log the active allocator at server startup and report it in INFO as mem_allocator (buffer widened to fit the version string) - Forward a JEMALLOC variable through Makefile.fkvs (JEMALLOC=ON) - Install jemalloc in the Dockerfile behind an ENABLE_JEMALLOC build arg - Document building with jemalloc on macOS and Linux (docs/jemalloc.md, README) Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The hashtable was a fixed 8092-bucket separate-chaining table with no resize path, so distinct-key workloads (e.g. benchmark -r) piled entries into ever-longer chains. set/get/delete walk the chain, making each op O(load factor) and N inserts O(N^2/buckets) — throughput collapsed as the keyspace grew. Add Redis dict-style incremental resizing: - hashtable_t now holds two sub-tables plus a rehash cursor; a resize doubles capacity at load factor 1.0 and migrates one bucket per insert, so no single op stalls on a full rehash - new keys insert into the new table during a resize (old table only drains, guaranteeing termination); lookups/deletes consult both tables - migration only relinks existing nodes, never copies keys/values - sizes are powers of two, so bucket index is a mask, not a division; TABLE_SIZE 8092 -> 8192 - KEYS and expire_sweep now scan both sub-tables so no key is missed mid-resize With this, set/get return to amortized O(1) and -r throughput stays flat as the keyspace grows instead of degrading. Also add a stress test covering inserts, mid-resize reads, in-place updates and deletes across many resize generations, and add a get_allocator_name stub to test_integration (it does not link memory.c). Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The -r flag generates a unique key per insertion (a per-process random prefix plus a monotonic counter), not uniformly random keys. Update the usage string and benchmarking guide to say "unique" to match behavior. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Each worker generated its key and malloc'd the command buffer inside the send loop, so -r measurements included client-side key generation and a malloc/free per request. Pre-build all command buffers per worker before the start gate: unique-key mode builds one distinct command per request, other modes build a single reused buffer. The timed loop now only calls send() on a pre-built buffer. This makes -r measure server throughput more directly (its result is now in line with the fixed-key path on the client side, differing only by the server's insert-vs-update work). Pre-build memory scales with the request count, which is the same order as the keyspace the server stores. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Make FKVS_ENABLE_JEMALLOC default ON on Linux (off elsewhere), mirroring the FKVS_ENABLE_IO_URING pattern. When jemalloc is enabled but the library is not found, the build now warns and falls back to the system allocator instead of failing — so a Linux build without libjemalloc still succeeds. - CMakeLists: platform-aware option default; missing jemalloc is a status message, not a fatal error - Dockerfile: ENABLE_JEMALLOC build arg now defaults to ON - Makefile.fkvs: only pass -DFKVS_ENABLE_JEMALLOC when JEMALLOC is set explicitly, so the plain shortcut inherits the platform default - docs/README: document jemalloc-by-default-on-Linux and how to opt out Verified via Docker: the default image links libjemalloc and reports the jemalloc version at startup; --build-arg ENABLE_JEMALLOC=OFF falls back to the system allocator. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Document throughput across pipeline depth, event-loop backend (epoll/io_uring) and allocator (jemalloc/system), with the machine configuration and methodology so the numbers are interpretable. Includes both the fixed-key (update-in-place) sweep and the -r allocation-heavy case, plus notes that the Linux figures are from a virtualized VM over loopback TCP and are relative, not absolute. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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