Repository navigation
Runtime + Network Stack - #5
Closed
supernomad wants to merge 166 commits into
Closed
supernomad wants to merge 166 commits into
supernomad wants to merge 166 commits into
Conversation
This includes a decent revamp and simplification/efficiency updates for the PMTU + NDP/ARP handling. There should be no system calls for time going forward and they are vastly simpler.
This moves away from as much direct byte buffer interactions as possible in favor of typed struct casting.
Plan to decompose the 11,300-line tcp/mod.rs into focused modules (handler, listener, connection, inbound, timers, transmit) and split 8,200 lines of tests into category-based test files. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
21-task plan for decomposing tcp/mod.rs (11,300 lines) into focused modules and categorized test files. Each task is one commit with cargo test verification. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move connect(), connect_with_config(), and initiate_close() methods into a dedicated connection.rs module. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move poll_send() method into its own transmit.rs module for better code organization, continuing the tcp handler decomposition. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move poll_timers() and evict_stale() methods into a dedicated timers module, continuing the mechanical decomposition of the monolithic tcp/mod.rs handler. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move TcpHandler struct definition, constructor, get_connection, get_connection_mut, remove_connection, and constants (INITIAL_RTO_MS, SYN_R2_THRESHOLD_MS) into handler.rs. Re-export TcpHandler from mod.rs so sibling modules and external code continue to work unchanged. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move all inbound segment processing (process_ipv4, process_ipv6, process_segment, process_listen, process_syn_received, process_syn_sent, process_established, process_teardown) and the is_segment_acceptable free function into inbound.rs. mod.rs now contains only module declarations, the TcpHandler re-export, and the test module. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Move ~8200 lines of inline tests from mod.rs into src/net/handler/tcp/tests/ with category-based organization: - tests/mod.rs: shared imports, constants, and helper functions - handshake.rs: 3-way handshake, simultaneous open, window scale - data_transfer.rs: in-order/out-of-order data, poll_send, PSH flag - retransmission.rs: fast retransmit, RTO, RTT estimation, limited transmit - teardown.rs: FIN handling, close lifecycle, half-close, linger - delayed_ack.rs: deferred ACK, flush on second segment, timer flush - nagle.rs: Nagle algorithm, TCP_NODELAY - keepalive.rs: keep-alive probes, linger options - timestamps.rs: PAWS validation - persist.rs: zero-window probing - sack.rs: SACK blocks, scoreboard, SACK recovery - ecn.rs: ECN negotiation, CE detection, CWR/ECE flags - edge_cases.rs: RST handling, challenge ACKs, SWS avoidance - congestion_tests.rs: CUBIC slow start, F-RTO All 98 TCP tests pass unchanged. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Captures analysis of hot-path bottlenecks (per-packet Instant::now(), redundant tsval computation, Vec allocations) and planned changes to eliminate them. Target: millions of pkt/s for TCP echo. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
7-task plan covering: now threading through dispatch, tsval pre-computation, stack array replacements, and connection constructor cleanup. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The runtime loop caches `now = coarsetime::Instant::now()` and passes it through the handler chain. The IPv4/IPv6 handlers were calling the no-now TCP wrappers which called Instant::now() internally — wasting a syscall per packet. Now both dispatch sites call the _with_now variants directly. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The no-`now` wrappers (process_ipv4 and process_ipv6) that internally called Instant::now() are removed. The _with_now variants are renamed to be the primary API (process_ipv4 and process_ipv6), keeping the `now: Instant` parameter. All callers updated accordingly. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
…t::now() Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Analyze 20x performance gap between TCP echo (560K pkt/s) and UDP echo (11M pkt/s). Identify root causes: 4 data copies per echo, redundant option parsing, software checksums on VETH, cache-unfriendly Tcb layout, and instruction cache pressure from cold paths. Propose 8-task plan targeting 2-5M pkt/s: consolidated option parsing, VETH checksum bypass, fast-path for established state, RingBuffer splice, Tcb field reordering, cached connection indices, and cold path extraction. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Parse TCP timestamp and SACK block options once per segment in process_segment, replacing 3 redundant parse_timestamp calls and 2 redundant parse_sack_blocks calls in process_established/process_teardown. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Add a fast-path at the top of process_established that handles the most common case (in-order data with valid new ACK, no special flags, not in recovery, no OOO segments) in a single streamlined block with minimal branches. On any check failure (PAWS, window space), control falls through to the existing slow path which remains unchanged. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
…o-copy echo Add RingBuffer::transfer() to move data directly between ring buffers without an intermediate user-space buffer, eliminating 2 memcpys. Add TcpStream::splice() future that uses transfer() internally. Update tcp-echo-server example to use splice() instead of read/write. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Group hot fields (rcv_nxt, snd_nxt, snd_una, snd_wnd, state, flags) into the first 1-2 cache lines (64-128 bytes) to improve L1d hit rate on the per-packet fast path. Fields are organized into hot/warm/ack processing/congestion/RTT/cold tiers based on access frequency. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
TcpRead, TcpWrite, and TcpSplice poll methods previously called get_connection_mut() which does an O(n) linear scan of Vec<Tcb> on every poll. Add a Cell<usize> cached index to TcpStream that enables O(1) lookup on the fast path, with automatic fallback to linear scan when the index becomes stale due to connection table mutations. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Extract three rarely-taken branches from process_established's slow path into dedicated #[inline(never)] helper methods to reduce instruction cache pressure on the hot path: - handle_rst_established: RST handling with exact-match removal + challenge ACK - handle_syn_established: challenge ACK for SYN in synchronized state - handle_ooo_data: out-of-order data storage + SACK block generation Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
No description provided.