From 5d9e3ac039b2c2fd62b71256e7368c212b6f475e Mon Sep 17 00:00:00 2001
From: Andrew Marshall <andrew@johnandrewmarshall.com>
Date: Wed, 16 Aug 2023 18:40:22 -0400
Subject: [PATCH] opensubdiv: Fix flaky build with CUDA and high parallelism

See upstream issue:
https://github.com/PixarAnimationStudios/OpenSubdiv/issues/1313
---
 pkgs/development/libraries/opensubdiv/default.nix | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pkgs/development/libraries/opensubdiv/default.nix b/pkgs/development/libraries/opensubdiv/default.nix
index 06d65be106da..b0ff4b528864 100644
--- a/pkgs/development/libraries/opensubdiv/default.nix
+++ b/pkgs/development/libraries/opensubdiv/default.nix
@@ -47,6 +47,11 @@ stdenv.mkDerivation rec {
       "-DNO_OPENCL=1"
     ];
 
+  preBuild = let maxBuildCores = 16; in lib.optionalString cudaSupport ''
+    # https://github.com/PixarAnimationStudios/OpenSubdiv/issues/1313
+    NIX_BUILD_CORES=$(( NIX_BUILD_CORES < ${toString maxBuildCores} ? NIX_BUILD_CORES : ${toString maxBuildCores} ))
+  '';
+
   postInstall = "rm $out/lib/*.a";
 
   meta = {