From 9a8f9f84cc1672c45c2d204d9c234c932a8cb623 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= Date: Thu, 1 Dec 2016 22:53:37 +0100 Subject: [PATCH] daemon: Buffer data sent to clients by the 'export-path' RPC. Before that we'd have STDERR_WRITE round trips for very small amounts of data, ranging from a few bytes for the metadata of nars to the size of one file being exported. With this change, something like: guix archive --export /gnu/store/5rrsbaghh5ix1vjcicsl60gsxilhjnf2-coreutils-8.25 | dd of=/dev/null reports a throughput of 35 MB/s instead of 25 MB/s before. * nix/nix-daemon/nix-daemon.cc (TunnelSink): Inherit from 'BufferedSink' rather than 'Sink'. Rename 'operator ()' to 'write'. (performOp) : Add 'sink.flush' call. --- nix/nix-daemon/nix-daemon.cc | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/nix/nix-daemon/nix-daemon.cc b/nix/nix-daemon/nix-daemon.cc index 9b29b3e91d..682f9a2b5b 100644 --- a/nix/nix-daemon/nix-daemon.cc +++ b/nix/nix-daemon/nix-daemon.cc @@ -203,11 +203,11 @@ static void stopWork(bool success = true, const string & msg = "", unsigned int } -struct TunnelSink : Sink +struct TunnelSink : BufferedSink { Sink & to; - TunnelSink(Sink & to) : to(to) { } - virtual void operator () (const unsigned char * data, size_t len) + TunnelSink(Sink & to) : BufferedSink(64 * 1024), to(to) { } + virtual void write(const unsigned char * data, size_t len) { writeInt(STDERR_WRITE, to); writeString(data, len, to); @@ -433,6 +433,7 @@ static void performOp(bool trusted, unsigned int clientVersion, startWork(); TunnelSink sink(to); store->exportPath(path, sign, sink); + sink.flush(); stopWork(); writeInt(1, to); break;