cpu affinity

Author: randomizedcoder

Makefile

@@ -8,11 +8,13 @@ all: hp0 hp3
 hp0:
 	scp -C ./hp0/* hp0:
 	scp -C ./modules/* hp0:
+	scp -C ./scripts/* hp0:
 	scp -C ./nix_switch.bash hp0:
 
 hp3:
 	scp -C ./hp3/* hp3:
 	scp -C ./modules/* hp3:
+	scp -C ./scripts/* hp3:
 	scp -C ./nix_switch.bash hp3:
 
 #

hp0/configuration.nix

@@ -27,6 +27,7 @@
       ./hosts.nix
       ./firewall.nix
       ./il8n.nix
+      ./systemdSystem.nix
       ./systemPackages.nix
       ./home-manager.nix
     ];

hp3/configuration.nix

@@ -27,6 +27,7 @@
       ./hosts.nix
       ./firewall.nix
       ./il8n.nix
+      ./systemdSystem.nix
       ./systemPackages.nix
       ./home-manager.nix
     ];

modules/systemdSystem.nix

@@ -0,0 +1,14 @@
+{ config, pkgs, ... }:
+
+{
+  # https://github.com/NixOS/nixpkgs/blob/095f1acb70302bd74cd5f3ab02a64bdfac36daa8/nixos/modules/system/boot/systemd.nix#L534
+  # https://discourse.nixos.org/t/overriding-modifying-systemd-unit-file/45621/7
+
+  # https://mynixos.com/nixpkgs/options/systemd
+  systemd.extraConfig = "CPUAffinity=2-7";
+
+  #https://mynixos.com/options/systemd.user
+  systemd.user.extraConfig = "CPUAffinity=2-7";
+  # create your own service
+  # https://discourse.nixos.org/t/how-to-use-toplevel-overrides-for-systemd/12501
+}

nix_switch.bash

@@ -2,3 +2,6 @@
 #
 sudo cp ./*.nix /etc/nixos/
 sudo nixos-rebuild switch
+
+
+#sudo ln -s /run/current-system/sw/bin/bash /usr/bin/bash

scripts/pin_nic_irqs.bash

@@ -0,0 +1,45 @@
+#!/usr/bin/bash
+#
+# This script pins iwlwifi and enp1 to cores 0-1
+#
+# https://www.kernel.org/doc/Documentation/IRQ-affinity.txt
+# https://linux-kernel-labs.github.io/refs/heads/master/lectures/interrupts.html#interrupt-handling-in-linux
+# in future consider
+# https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/performance_tuning_guide/network-rps
+
+# [das@hp0:~]$ cat /proc/interrupts | grep wifi
+#   86:          0          0          0    4361163          0          0          0          0  IR-PCI-MSIX-0000:03:00.0    0-edge      iwlwifi:default_queue
+#   87:     527141          0          0          0          0          0          0          0  IR-PCI-MSIX-0000:03:00.0    1-edge      iwlwifi:queue_1
+#   88:          0      36601          0          0          0          0          0          0  IR-PCI-MSIX-0000:03:00.0    2-edge      iwlwifi:queue_2
+#   89:          0          0     549109          0          0          0          0          0  IR-PCI-MSIX-0000:03:00.0    3-edge      iwlwifi:queue_3
+#   90:          0          0          0     393223          0          0          0          0  IR-PCI-MSIX-0000:03:00.0    4-edge      iwlwifi:queue_4
+#   91:          0          0          0          0    1776763          0          0          0  IR-PCI-MSIX-0000:03:00.0    5-edge      iwlwifi:queue_5
+#   92:          0          0          0          0          0     159677          0          0  IR-PCI-MSIX-0000:03:00.0    6-edge      iwlwifi:queue_6
+#   93:          0          0          0          0          0          0     295033          0  IR-PCI-MSIX-0000:03:00.0    7-edge      iwlwifi:queue_7
+#   94:          0          0          0          0          0          0          0     642178  IR-PCI-MSIX-0000:03:00.0    8-edge      iwlwifi:queue_8
+#   95:          0          0          0          0          3          0          0          0  IR-PCI-MSIX-0000:03:00.0    9-edge      iwlwifi:exception
+# grep iwlwifi /proc/interrupts | awk '{ print $1 }' | sed -e 's/://'
+
+echo "starting to pin"
+echo "BEFORE"
+echo "grep iwlwifi /proc/interrupts"
+grep iwlwifi /proc/interrupts
+
+for i in {86..95}
+do
+  echo "Loop:${i}"
+  echo "echo 0-1 > /proc/irq/${i}/smp_affinity_list"
+  echo 0-1 > /proc/irq/"${i}"/smp_affinity_list
+  echo "cat /proc/irq/${i}/smp_affinity_list"
+  cat /proc/irq/"${i}"/smp_affinity_list
+done
+
+echo "AFTER"
+echo "grep iwlwifi /proc/interrupts"
+grep iwlwifi /proc/interrupts
+
+#[das@hp0:~]$ grep eno /proc/interrupts
+#  83:          0          0          0          0          0          0          0          0  IR-PCI-MSIX-0000:05:00.0    0-edge      eno1
+
+echo "echo 0-1 > /proc/irq/83/smp_affinity_list"
+echo 0-1 > /proc/irq/83/smp_affinity_list