From 788d8769f78d74b9491526c9d34849e525942c42 Mon Sep 17 00:00:00 2001
From: jrp2014 <jrp2014@users.noreply.github.com>
Date: Sat, 3 Aug 2019 12:34:30 +0100
Subject: [PATCH] nixos/virtualisation.hypervGuest: use elevator=noop

Microsoft recommends the NOOP I/O scheduler for disk performance in HYPER-V:

https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/best-practices-for-running-linux-on-hyper-v

> NOOP is a first-in first-out queue that passes the schedule decision
> to be made by the hypervisor. It is recommended to use NOOP as the
> scheduler when running Linux virtual machine on Hyper-V.
---
 nixos/modules/virtualisation/hyperv-guest.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nixos/modules/virtualisation/hyperv-guest.nix b/nixos/modules/virtualisation/hyperv-guest.nix
index 0f1f052880c5f..adc2810a99398 100644
--- a/nixos/modules/virtualisation/hyperv-guest.nix
+++ b/nixos/modules/virtualisation/hyperv-guest.nix
@@ -32,7 +32,7 @@ in {
       ];
 
       kernelParams = [
-        "video=hyperv_fb:${cfg.videoMode}"
+        "video=hyperv_fb:${cfg.videoMode} elevator=noop"
       ];
     };