From d3c9fabbc20842318b9d0b8b0e3a385a7a3bf743 Mon Sep 17 00:00:00 2001
From: h7x4 <h7x4@nani.wtf>
Date: Tue, 21 Jul 2026 15:30:25 +0900
Subject: [PATCH] base/irqbalance: only start on multi-socket machines

---
 base/services/irqbalance.nix | 22 ++++++++++++++++++++--
 1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/base/services/irqbalance.nix b/base/services/irqbalance.nix
index 078e569..09f51ce 100644
--- a/base/services/irqbalance.nix
+++ b/base/services/irqbalance.nix
@@ -1,4 +1,22 @@
-{ ... }:
+{ config, pkgs, lib, ... }:
+let
+  cfg = config.services.irqbalance;
+in
 {
   services.irqbalance.enable = true;
-}
\ No newline at end of file
+
+  # irqbalance only has meaningful work to do on multi-socket machines, so
+  # skip starting it pointlessly everywhere else.
+  systemd.services.irqbalance.serviceConfig.ExecCondition = let
+    isMultiSocket = pkgs.writeShellApplication {
+      name = "irqbalance-is-multi-socket";
+      runtimeInputs = [ pkgs.coreutils ];
+      text = ''
+        sockets=$(cat /sys/devices/system/cpu/cpu*/topology/physical_package_id | sort -u | wc -l)
+        [ "$sockets" -gt 1 ]
+      '';
+    };
+  in lib.mkIf cfg.enable [
+    (lib.getExe isMultiSocket)
+  ];
+}