--- a/python/mozbuild/mozbuild/frontend/emitter.py
+++ b/python/mozbuild/mozbuild/frontend/emitter.py
@@ -470,17 +470,17 @@ class TreeMetadataEmitter(LoggingMixin):
             if libname in ('gkrust', 'gkrust-gtest'):
                 if profile_name == 'dev':
                     expected_profile = {
                         'opt-level': 1,
                         'debug': True,
                         'rpath': False,
                         'lto': False,
                         'debug-assertions': True,
-                        'codegen-units': 1,
+                        'codegen-units': 4,
                         'panic': 'abort',
                     }
                 else:
                     expected_profile = {
                         'opt-level': 2,
                         'debug': True,
                         'rpath': False,
                         'lto': True,

--- a/toolkit/library/gtest/rust/Cargo.toml
+++ b/toolkit/library/gtest/rust/Cargo.toml
@@ -27,17 +27,17 @@ harness = false
 
 # Explicitly specify what our profiles use.
 [profile.dev]
 opt-level = 1
 debug = true
 rpath = false
 lto = false
 debug-assertions = true
-codegen-units = 1
+codegen-units = 4
 panic = "abort"
 
 [profile.release]
 opt-level = 2
 debug = true
 rpath = false
 lto = true
 debug-assertions = false

--- a/toolkit/library/rust/Cargo.toml
+++ b/toolkit/library/rust/Cargo.toml
@@ -25,17 +25,17 @@ harness = false
 
 # Explicitly specify what our profiles use.
 [profile.dev]
 opt-level = 1
 debug = true
 rpath = false
 lto = false
 debug-assertions = true
-codegen-units = 1
+codegen-units = 4
 panic = "abort"
 
 [profile.release]
 opt-level = 2
 debug = true
 rpath = false
 lto = true
 debug-assertions = false