diff --git a/python/mozbuild/mozbuild/frontend/emitter.py b/python/mozbuild/mozbuild/frontend/emitter.py
index 8de24fd8ee45..759745e9b129 100644
--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -475,7 +475,7 @@ class TreeMetadataEmitter(LoggingMixin):
                         'rpath': False,
                         'lto': False,
                         'debug-assertions': True,
-                        'codegen-units': 1,
+                        'codegen-units': 4,
                         'panic': 'abort',
                     }
                 else:
diff --git a/toolkit/library/gtest/rust/Cargo.toml b/toolkit/library/gtest/rust/Cargo.toml
index 8d6e6b6ae6df..c17afbd13574 100644
--- a/toolkit/library/gtest/rust/Cargo.toml
+++ b/toolkit/library/gtest/rust/Cargo.toml
@@ -32,7 +32,7 @@ debug = true
 rpath = false
 lto = false
 debug-assertions = true
-codegen-units = 1
+codegen-units = 4
 panic = "abort"
 
 [profile.release]
diff --git a/toolkit/library/rust/Cargo.toml b/toolkit/library/rust/Cargo.toml
index 586ef94fb94f..1d1f0cdbe24d 100644
--- a/toolkit/library/rust/Cargo.toml
+++ b/toolkit/library/rust/Cargo.toml
@@ -30,7 +30,7 @@ debug = true
 rpath = false
 lto = false
 debug-assertions = true
-codegen-units = 1
+codegen-units = 4
 panic = "abort"
 
 [profile.release]