From 51a23844dd2702658219883a55f299bfeecd344f Mon Sep 17 00:00:00 2001
From: Luna Nova <git@lunnova.dev>
Date: Fri, 10 Apr 2026 10:28:52 -0700
Subject: [PATCH] =?UTF-8?q?rocmPackages.composable=5Fkernel:=20use=20jemal?=
 =?UTF-8?q?loc=20at=20build=20time=20to=20speed=20up=20build=20by=20?=
 =?UTF-8?q?=E2=89=887%?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 pkgs/development/rocm-modules/composable_kernel/base.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/rocm-modules/composable_kernel/base.nix b/pkgs/development/rocm-modules/composable_kernel/base.nix
index 9f1353ac7e05..1d56a0caa9db 100644
--- a/pkgs/development/rocm-modules/composable_kernel/base.nix
+++ b/pkgs/development/rocm-modules/composable_kernel/base.nix
@@ -11,6 +11,7 @@
   hipify,
   gitMinimal,
   gtest,
+  jemalloc,
   zstd,
   buildTests ? false,
   buildExamples ? false,
@@ -87,6 +88,9 @@ stdenv.mkDerivation (finalAttrs: {
   strictDeps = true;
   enableParallelBuilding = true;
   env.ROCM_PATH = clr;
+  # Speed up build by ~7% with jemalloc (template torture test workload means allocation heavy clang invocations)
+  env.LD_PRELOAD = "${jemalloc}/lib/libjemalloc.so";
+  env.MALLOC_CONF = "background_thread:true,metadata_thp:auto,dirty_decay_ms:10000,muzzy_decay_ms:10000";
 
   cmakeFlags = [
     (lib.cmakeBool "MIOPEN_REQ_LIBS_ONLY" miOpenReqLibsOnly)