Set TCP_NODELAY on the ps2link request socket#25
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ps2link fileio is a synchronous sequence of small request/response exchanges over the TCP request channel. With Nagle enabled on the client side, each response collides with the PS2 delayed ACKs and stalls ~200 ms, capping file serving at roughly 4 KB/s on a real console: a 424 KB texture took 106 seconds to serve, and a homebrew game booting entirely over host: took 10 minutes. With TCP_NODELAY on the SOCK_STREAM connect path the same texture serves in about a second and the same boot takes ~30 seconds (measured on a PAL console over 100 Mbit ethernet, Windows host); streaming 22 kHz music over host: becomes usable.
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Problem
ps2link fileio is a synchronous sequence of small request/response exchanges over the TCP request channel (port 0x4711). With Nagle enabled on the client side, each response collides with the PS2 stack delayed ACKs and stalls roughly one delayed-ACK period (~200 ms) per exchange.
Measured effect (PAL console, 100 Mbit ethernet, Windows host, ps2link v1.9.1): file serving capped at about 4 KB/s - a 424 KB texture took 106 seconds, and a homebrew game loading all of its assets over
host:took 10 minutes to boot.Fix
Set
TCP_NODELAYon theSOCK_STREAMconnect path innetwork_connect()(UDP sockets unaffected). Small responses then leave immediately instead of waiting for the ACK of the previous segment.With the patch, the same texture serves in about a second and the same game boots in ~30 seconds; streaming 22 kHz PCM music over
host:becomes usable. Verified on real hardware against ps2link v1.9.1; behaviour on Linux/macOS builds is the same code path (netinet/tcp.hinclude added for those platforms).🤖 Generated with Claude Code