From 71b46112f7d2eac045ae932f8b14d6d5db8ee068 Mon Sep 17 00:00:00 2001
From: HoneyHazard <8847050+HoneyHazard@users.noreply.github.com>
Date: Tue, 4 Aug 2026 23:40:17 -0700
Subject: [PATCH] Opt wiremix's capture streams out of wireplumber state
 persistence

wireplumber's state-stream.lua persists volume/mute/target to disk
(~/.local/state/wireplumber/stream-properties, write+fsync+rename,
debounced) for any node whose media.class matches "Stream/*" - which is
what a pw_stream gets by default when no media.class is set, exactly
wiremix's capture streams (wirehose/stream.rs::capture_node). These
streams are purely internal metering taps with no volume/mute/target of
their own worth remembering across launches, so every Props update on
one is wasted disk I/O and wireplumber policy work.

state-stream.lua already supports a per-node opt-out, checked before any
of that work happens: stream_props["state.restore-props"] and
["state.restore-target"]. Setting both to "false" on the capture stream
skips it entirely.

Confirmed via strace that wireplumber's state-file write path is real
and not free, but on investigation the dominant cost on a real system
turned out to be an unrelated background process (a stabilizer tone
generator repeatedly recreating its own stream) rather than wiremix's
captures specifically - so this is a legitimate, low-risk correctness
fix (an internal tap shouldn't be treated like a real user stream) more
than a load-bearing performance fix on its own. Still worth doing: it
costs nothing for any wiremix build, and removes real per-event
disk I/O that has no reason to happen for these streams.

Tested: cargo test (144/144), cargo fmt --check / cargo clippy -- -D
warnings / cargo doc (matching wiremix's CI) all clean.
---
 src/wirehose/stream.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/wirehose/stream.rs b/src/wirehose/stream.rs
index 90919e1..1cde11c 100644
--- a/src/wirehose/stream.rs
+++ b/src/wirehose/stream.rs
@@ -98,6 +98,18 @@ pub fn capture_node(
         *pipewire::keys::TARGET_OBJECT => String::from(serial),
         *pipewire::keys::STREAM_MONITOR => "true",
         *pipewire::keys::NODE_NAME => "wiremix-capture",
+        // wireplumber's state-stream.lua persists volume/mute/target to disk
+        // (~/.local/state/wireplumber/stream-properties) for any node whose
+        // media.class matches "Stream/*", which this capture stream does by
+        // default. That's real per-event disk I/O (write+fsync+rename,
+        // debounced but still frequent) for a purely internal metering tap
+        // that has no volume/mute/target of its own worth remembering -
+        // these two properties are wireplumber's own opt-out mechanism
+        // (checked directly in state-stream.lua before any of that work
+        // happens), and eliminate the cost entirely rather than just
+        // reducing how many capture streams exist at once.
+        "state.restore-props" => "false",
+        "state.restore-target" => "false",
     };
     if capture_sink {
         props.insert(*pipewire::keys::STREAM_CAPTURE_SINK, "true");