From 61685d4a6e107972aed36dbdee42fef193017c7b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sandro=20J=C3=A4ckel?= <sandro.jaeckel@gmail.com>
Date: Thu, 23 Feb 2023 00:12:15 +0100
Subject: [PATCH] nix: improve substituter speed

---
 overlays/default.nix                              | 13 +++++++++++++
 overlays/nix-increase-substituter-threadpool.diff | 14 ++++++++++++++
 2 files changed, 27 insertions(+)
 create mode 100644 overlays/nix-increase-substituter-threadpool.diff

diff --git a/overlays/default.nix b/overlays/default.nix
index dcbe3de1..6b47b583 100644
--- a/overlays/default.nix
+++ b/overlays/default.nix
@@ -69,6 +69,19 @@ with final; {
 
   mlat-client = python3Packages.callPackage ./mlat-client.nix { };
 
+  nixVersions = prev.nixVersions // {
+    stable = prev.nixVersions.stable.overrideAttrs (oldAttrs: {
+      patches = oldAttrs.patches or [ ] ++ [
+        ./nix-increase-substituter-threadpool.diff
+        # request compression
+        (fetchpatch {
+          url = "https://github.com/NixOS/nix/pull/7712.patch";
+          sha256 = "sha256-84C27RxOYi/pamvWLJ/NWsc9zf6VhUAA57llIn8DAT4=";
+        })
+      ];
+    });
+  };
+
   openssh = prev.openssh.overrideAttrs (_: {
     # takes 30 minutes
     doCheck = false;
diff --git a/overlays/nix-increase-substituter-threadpool.diff b/overlays/nix-increase-substituter-threadpool.diff
new file mode 100644
index 00000000..9e243274
--- /dev/null
+++ b/overlays/nix-increase-substituter-threadpool.diff
@@ -0,0 +1,14 @@
+diff --git a/src/libstore/misc.cc b/src/libstore/misc.cc
+index fb985c97b..a509d6f4d 100644
+--- a/src/libstore/misc.cc
++++ b/src/libstore/misc.cc
+@@ -102,7 +102,8 @@ void Store::queryMissing(const std::vector<DerivedPath> & targets,
+     downloadSize_ = narSize_ = 0;
+ 
+     // FIXME: make async.
+-    ThreadPool pool(fileTransferSettings.httpConnections);
++	// https://github.com/NixOS/nix/issues/5118
++    ThreadPool pool(300);
+ 
+     struct State
+     {